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Hardware Hacker IV

i

Don Lancaster’s

Hardware Hacker

Selected reprints — volume IVElectronics Now series (January 1992 - January 1994)

Copyright c. 1994 by Don Lancaster and Synergetics PressBox 809, Thatcher, AZ 85552 (602) 428-4073

ISBN 1-882193-04-0

Book-on-demand self-published using the Apple IIe computer, a duplex LaserJet and the PostScript language. All graphics were done in their entirety by ProDOS AppleWriter 2.1.

Hardware Hacker IV

ii

Hardware Hacker IV

iii

Introduction

Welcome to the fourth volume in our ongoing series of my Hardware Hacker reprints from Electronics Now magazine. This volume includes the January 1992

through January 1994 columns.

As before, I do use the term "hacker" in its original context, namely anyone who is

genuinely interested in pushing all the limits of software and hardware and is

willing to do so in a fully cooperative, low cost and sharing network environment.

I’ve tried to expand the topics beyond the strict boundaries of traditional

electronics. Going into the science and math subjects many of you have asked for

over our voice helpline.

I still get lots of pseudoscience and "free energy" questions. So, focus areas of this

volume include thermodynamics, power transfer theorems, and related engineering

fundamentals. Stuff that outright precudes all perpetual motion scams. At the same

time, I have indexed and listed most of the fake pseudoscience sources. Mostly,

because they make wondrously bizarre reading, I guess.

Some of the more popular subjects in this volume include distant FM reception,

Newtek’s Video Toaster, advanced halftone imaging, and new solar energy

developments. Plus updates on wavelets, caller ID, and GPS navigation. And great

stuff on cubic splines, UFO’s, and phone interfaces.

Preprints and reprints of most of my columns are also available electronically via

GEnie PSRT. Presented in both PostScript and Adobe Acrobat formats. For GEnie

access, have your modem dial (800) 638-8369. After the prompt, enter JOINGENIE.

When you are later asked for your keycode, enter DMD524.

I continue to offer my no-charge voice helpline at (602) 428-4073, and offer free

referrals from our Synergetics Consultant’s Network. I’ve also got a free and newly

expanded Hardware Hacker Inside Secrets and catalog waiting for you when you

call or write. You can also grab this as SYNCAT1.PS off GEnie PSRT, or else

request one through my Internet address of [email protected].

The Electronics Now subscription number is (516) 293-3000.

Hardware Hacker IV

iv

About the Author

As he said in his classic Incredible Secret Money Machine II, Don Lancaster

writes books. And quests tinajas.

Microcomputer pioneer and guru Don Lancaster is the author of 33 books, 2 videos,

and countless articles. These include his TTL Cookbook and CMOS Cookbook

internationally published million seller classics. Don is considered by some to be

the father of the personal computer, for his early ground-breaking work with hacker

digital electronics and low cost video terminal displays. He is considered by others

to be the patron saint of the Walter Mitties of the World. And by yet others as the…

Uh, I guess we better skip that one.

Don is the Hardware Hacker in Electronics Now (516) 293-3000, runs his Resource Bin in Nuts & Volts (714) 371-8497, and is the Blatant Opportunist in Midnight Engineering (719) 254-4558. Don is also the sysop for GEnie PSRT, a leading

Hardware hacking, PostScript, laser publishing, and money machine on-line

resource. His Ask the Guru columns continue to be published electronically on

PSRT. For fast GEnie modem access, dial (800) 638-8369. Then JOINGENIE and

DMD524.

Don is also the head honcho of Synergetics, a new-age design and consulting firm

that specializes in computer applications, laser printing, PostScript development

work, electronic prototypes, Book-on-demand publishing, technical writing, and

innovative software design. His avocations include firefighting, cave exploration,

bicycling, and, of course, tinaja questing.

Don maintains a no-charge voice helpline at (602) 428-4073. He does welcome your

calls and letters. The best calling times are 8-5 weekdays, Mountain Standard Time.

Referrals to Don’s Synergetics Consultant’s Network are available through this

same number.

Hardware Hacker

v

more . . .

Table of Contents

Caller ID chips updatePerpetual motion againNew wavelets sharewareCommon lab test pitfallsLumeloid and Lepcon films

Using the IC masterWavelets info updateAnother Caller ID chipPiano & organ resourcesMusical note frequencies

Laser printing repairsSync separator circuitGPS navigation updateVideo interface moduleHacking Super Nintendo

FM stereo broadcastersSuper Nintendo updateCD to car radio adaptorsDYS and other resourcesOckham’s razor revisited

Dye-based solar energy Another sad patent storyNeo-Geo interface cablesMicro-avionics newsletterRGB monitor fundamentals

Santa Claus machine BBSDirect toner breakthroughLaser printer repair videoSynchronous rectifier ideasFundamentals of correllation

Electronic halftonesApple’s PhotoGradeConsultants networkTwo great new booksMarketing your ideas

Alternate action latchesHistogram equalizationGamma curve correctionDigital image processingSemiconductor IC houses

Distant FM receptionUFO resources listingTV/FM booster circuitsUHF & VHF amplifiersPseudoscience research

Conventional currentsAssorted wondermentsFM Yagi antenna designNavigation & navicubesTwo new piezo rate gyros

High side FET driversDrawing semilog plotsLaser printer repair kitsResonance fundamentalsFar East electronic sources

Relaxation oscillatorsNewTek’s video toasterBroadcast trade journalsSyncronizing video sourcesElectric Discharge Machining

Hardware Hacker

vi

Epoxy encapsulation mythsNichrome & resistance wireSemiconductor suppliers IIIFCC part 68 phone interfaceCopy protection absurdities

Using cubic splinesSwitchmode resourcesElectrorheological fluidsNational’s simple switcherNon-ionizing radiation safety

Video game repair videosPiezoelectric fundamentalsUnderstanding Curie PointsSimple home EDM machiningStunning new ic opportunities

Steam calliope sourcesMicropower oscillatorsAvoiding energy scamsThermodynamic basicsThe comm trade journals

Short haul telemetryMax-min slope theorySETI books & resourcesUnique new optical linkMaximum power transfers

A flying car newsletterPhotopolymer resourcesAmateur television booksRoyalty-free real PostScript!BASIC Stamp microcontroller

Single station FM trapsFM DX reception updateFree GPS receiver boardsResources for "free energy"Nonlinear graphic secrets

Pulse monitor resourcesNew wireless comm magAn update on free energyAerobic exercise softwareThermoelectric guidelines

Magic resources listingDialog and Usenet accessData compression secretsAlternator to stepper videoGaining comm transparency

Digital photo imagingMagnetic field resourcesFluxgate compass papersA pair of new GPS booksError diffusion techniques

Digital Bogey contestMultimedia resourcesCTCSS tone squelchingCoin mechanism sourcesLow distortion sinewaves

Hacker’s data exchangeAdobe’s Acrobat systemNew pseudoscience magVoice messaging circuitsSpecial effects resources

Don Lancaster’s

Hardware HackerJanuary, 1992

Caller ID chips updatePerpetual motion againNew wavelets sharewareCommon lab test pitfallsLumeloid and Lepcon films

49.1

Fig. 1 – WHAT IS THE REAL POWER being consumed in this test circuit? There’s no way to tell with the setup shown. But you can safely bet that it is probably not anywhere near 440 watts.

Motors andMagnets

Load

4 amps

110Volts

ACpower

line

Wavelets. We have got lots of wavelets. You getcher wavelets here. As we’ve discovered a number of

times before, wavelets are a stunning new math concept that is profoundly changing virtually all the advanced electronic topics. A failure to learn wavelets now is the same as volun- teering for early retirement.

We’ve already seen that Jones and Bartlett has published THE great new wavelets book, and that the Ultra- wave Explorer from the Aware folks is one fine commercial wavelet study and development program.

But the big news is that I’ve just posted full working PC shareware copies of the Wavelet Packet Library from Digital Diagnostics on GEnie PSRT as #365 WAVELET.PS.

Those of you into satellite dishes and microwave electronics are now probably familiar with Smith Charts, a handy graphical method of doing things like impedance matching and tuning. I have written a PostScript Smith Chart generator that lets you instantly create all your own Smith charts in any quantity, any size, any resolution, and any where in your publication. Check GEnie PSRT #367 SMITHCHT.PS for several freeware samples. Your downloading cost on this is around twenty one cents.

Perpetual Motion Again

I get an average of three to five helpline calls a week on "free energy"and other perpetual motion topics. Aswe have seen in the past, perpetual motion is definitely real as a historic and ongoing societal phenomenon. We have also seen that two ongoing sources of perpetual motion books, videos, and papers are High Energy Research and Lindsay Publications.

Now, I personally feel that looking for any free energy systems is rather dumb. First, because the desirability of any free energy ranks somewhere between Herpes and AIDS. Why? Be- cause this would obviously hasten thealready ongoing entropic heat death of the planet. If someone does in fact

find a free energy system, they shouldbe spanked and sent to bed without any supper. Or, better yet, chopped upand fed to the cows.

Second, because the odds of your accomplishing anything that’s even remotely useful involving free energyare stupendously low. Third, because your credibility starts out as less than zero and quickly plummets. Owing toprevious scams, the "not even wrong"research, and the "few-chips-shy-of- a-full-board" guilt by association.

And, finally, because there’s so much better to be doing. We’re sittingon the greatest mountain of new hardware hacking chips, tools, info, and concepts anywhere ever. Stuff that’s crying for hacker use, and stuff that is nearly certain to result in lots of interesting and profitable things. Why ignore the obvious?

Several of the recent callers were making measurements that were just plain wrong. Since I am one of the world’s foremost experts in gatheringincorrect, misleading, or meaningless lab data, I thought we might briefly focus on a few of the ways that casualmeasurements may not end up what they appear to be.

In general, you’ll always want to assume that all meter pointers and, especially, all of your digital numericdisplays are lying through their teeth. Or, if they are giving you a correct reading, the odds are overwhelming that the meaning and the underlying reasons for that reading are not at all what you had in mind.

Oscilloscopes do a far better job than the meters or digital displays at showing you what is really coming down. Even here, an uncompensated probe, the wrong setting, improper sync, an invisible glitch, any outband signals, or just a ground clip that is slightly too long can cause you wildlyincorrect results.

It is only when the same tests are run over and over again by different people under different circumstances that you can even remotely begin to trust your instruments. Even when repeated, that trust should only apply to the exact measuring conditions.

A ferinstance. Figure one shows you a seemingly simple method to measure ac power. You connect your new motors-and-magnets perpetual motion machine load to the ac power line through an ammeter and then separately measure the line voltage. Since power equals volts times amps, you just multiply your two readings together and you’ll have the input power. Right?

Wrong. Dead wrong.Let’s temporarily forget about any

noise, spikes, back-EMF effects, harmonics, and nonlinearities that are certain to be present with your new motors-and-magnets load. Assume a pure sinewave voltage and a similar current waveform. You have to take the phase of the current into account. You would get a zero phase shift witha purely resistive load. In a purely inductive load the voltage would leadthe current by 90 degrees. In a purely

49.2

Hardware Hacker

Fig. 2 – WHEN IS A REGULATOR NOT A REGULATOR? Any time that your load tries to source (rather than sink) power, a typical IC voltage regulator will shut down or else become unstable. There is no current path to ground.

Motors andMagnets

Load

Typical ICSeries Regulator

ref-+

+V

Fig. 3 – QUICKLY CLOSE THE PERFECT and lossless switch. And half of your circuit energy will vanish without a trace. Where did the energy go?

100µF

100 V

100µF

50 V

100µF

0 V

100µF

50 V

(open) (closed)

Energy = 0.5 Joules Energy = 0.25 Joules

capacitive load, the voltage will lag the current by 90 degrees.

Good old ELI THE ICE MAN. The voltage is ahead of the current in the eLi’s L inductor; the current is ahead of the voltage in his iCe capacitor.

And if you have any purely active load such as another generator, your current could end up phased by 180 degrees. Sourcing, not sinking.

Your actual power will end up the voltage times the current times the cosine of the phase angle between thetwo. If your voltmeter reads 110 and your ammeter reads 4, your actual circuit power will be 440 watts to a purely resistive load, ZERO to any purely inductive or capacitive load, and MINUS 440 watts to any purely active load. Or anything between, depending upon your phase angle.

Why is the power zero to a purely inductive load? Because of the phase angle. A math freak will tell you the full cycle cross product of a sine and its cosine is zero. Intuitively, on the

first quarter cycle, you have positive voltage and current. On your next quarter cycle, you will have positive voltage and negative current. On the next, negative voltage and negative current. And finally, negative voltage and positive current. Add them all up and average them all out and you end up with zero real power.

Yes, you will get lots of back-andforth reactive power that can give youreal fits. And hack off your electric utility. But your net real power into a pure inductive or capacitive load is precisely zero.

Thus, as far as power goes, all the voltmeter and ammeter readings are totally meaningless. And even less so in the presence of noise, back EMF’s, sparking, or harmonics.

Measuring Real Power

So how do you measure real and reactive power? The trick is that you have to multiply the instantaneous voltage and current together. Then

you sum to find the total power.The power of any arbitrary wave-

form is equal to the DC continuous power that would give you exactly the same amount of total heating in a purely resistive load.

You can do this measurement with a real wattmeter, or by measuring the rotational speed and direction of a watthour meter. The wattmeters and watt-hour meters are often available through Fair Radio Sales or Herbach and Rademan.

Electronically, you can use a multiplier chip or a special RMS power calculating circuit. Analog Devices is one leader in low cost power chips of this type.

Or graphically, you can take plots of all the exact voltage and current waveforms, split them up into time slices so narrow that the voltage or current does not change much, multiply the results of those slices and then sum the results.

Note that you must multiply first and then add. Never vice versa.

But you still do have to be careful. Nonlinearities, pulses, harmonics, motor back EMF effects and noise require special treatment. And most power measurement schemes have a crest factor limit which ruins their ac-curacy on strong but narrow pulses. Especially spikes and glitches.

For these reasons, it is extremely difficult to accurately measure your input power to a motors-and-magnets perpetual motion machine. If you do not know exactly what you are doing, all your results are guaranteed to be wildly wrong. And so, of course, will be your conclusions.

Figure two shows you a second measurement pitfall that the recent callers have all decided to ignore. A voltage regulator is always a voltage regulator, right?

Wrong. Dead wrong.Most popular voltage regulators are

only capable of sourcing current. If the load starts sourcing any power even briefly, there is no place for the current to go, and the regulator either shuts down or starts oscillating.

Thus, if you have a motors-andmagnets load, there could be times when the back EMF effects, spikes, commutator noise or whatever, will try to source power back into your supposed power source.

49.3

January, 1992

Fig. 4 – A FCC PART 68 INTERFACE is required any time you connect any circuit of your own to the phone line. While this interface can be both simple and cheap, the required submission and approval process is not.

phone line

user

The transformer is 1:1600 Ohms, with a 1500volt breakdown rating.

The zener diodes are3.9 volt devices, such

as a type 1N5228.

10 Ω

10 Ω

2200 pf

250 voltvaristor

Put in another way, typical power supplies and most regulators have wildly different impedances between when they source and sink power.

Note that any normally connected Zener diode will behave precisely the opposite – they are great power sinks but poor sources.

An output filter capacitor on your regulator is essential for grabbing andsmoothing out high frequency load sourcing variations.

Beyond proper output filtering, twoways around load sourcing effects areto hang enough of a resistive load on your regulator that the regulator will always output a net sourcing current. Most batteries are usually capable of sourcing and sinking any reasonable amount of current.

Figure three shows you yet another way to go astray. All bets are off if there is any sparking or arcing. It is physically impossible to instantly change the voltage across a circuit capacitor or the current through an inductor. The usual result when you try this is sparking or arcing.

Take a 100 microfarad capacitor and charge it on up to 100 volts. Your energy in any capacitor is…

E = 0.5 CV 2

or, in this case, 0.5 Joules of stored energy. Now, you close your lossless switch so you have two capacitors in parallel. The voltage must, of course, drop in half, since the same charge is now spread across twice your plate area. And by the same formula, you now have only 0.25 Joules of stored energy.

Question: Where did the rest of your energy go?

If you have a non-lossless switch of resistance R, the answer is easy. In the process of charging the second capacitor, the extra energy got burnedup in your resistor as heat during charging. But go through the chargingmath, and you’ll find that the loss of half the stored energy is a constant which is totally independent of the value of R!

If R equals zero, then you have to get a spark and radiated energy. But you still lose half of it, regardless of how good the switch is.

Thus, if there is any sparking or arcing whatsoever in your motors- and-magnets machine, your readings

are once again absolutely certain to be wrong.

Always think carefully about your measurements and how they could be wrong or misleading.

Lumeloid and Lepcon Films

We sure had a bunch of helpline calls over the new materials stuff I announced a column or two back and in our Hardware Hacker III reprints. I’ve picked up some more info, and have summarized where to go for more in our Lumeloid and Lepcon Solar Resources sidebar.

Let’s start off with the bottom line: Yes, this looks like it someday could be real. Maybe. At least in the lab. No, you cannot yet buy the stuff by the yard through your local K-Mart fabric department and staple it to yourroof. Yes, this is a great topic for a school paper or a science fair. And anincredible emerging research area.

On the other hand, working prototypes do not yet exist. And there are just enough "penny stock" and "mediahype" aspects to all this that I have lowered my rating from "solar breakthrough" to "an interesting potential solar development." But you could judge for yourself, just by picking up on the resources in our sidebar.

The key individual behind all this is one Alvin Marks and his company of Advanced Research Development. Their OTC pink sheet stock is traded under the name Phototherm. This is strictly an unregistered blue sky security, and trading remains illegal in Massachussets, the issuing state.

Marks is a credible, experienced, and independent researcher with a long history of successful energy,

optical film, and pollution control developments. Among other things, he developed the cheap glasses once used for 3-D movies.

And EPRI, that ultra-conservative Electric Power Research Institute electric utility consortium has seen fitto fund Marks with a modest researchgrant. Albeit a paltry one by EPRI standards. Coffee money.

The two key patents involved are #4,445,050 Device for Conversion of Light Power into Electric Power, and #4,574,161 An Ordered Dipolar Light-Electric Power Converter.

There is very little published to date. And all of it is single sourced. None appears to be peer reviewed or critiqued. A collection of reprints is now available free on request from Advanced Research Development. One original paper has shown up as Lumeloid Solar Plastic Films and Lepcon Submicron Dipolar Antennae on Glass, from the 1990 InternationalNew Energy Technology symposium published by the Planetary Assoc- iation for Clean Energy, located in Ottowa, Canada.

As we’ve seen a number of times inthe past, you can quickly research anytechnical topic by using the Dialog Information Service at your local library, and then can get any reprint by using either interlibrary loan or the UMI reprint service.

So what is the big deal here and how does it work? Your traditional methods of generating electricity from the sun are seriously flawed. The old mirrors-and-boilers method involves a thermodynamic cycle with a Carnot thermodynamic efficiency limit around 35 percent. Besides not

49.4

Hardware Hacker

Fig. 5 – PRE-APPROVED PART 68 INTERFACE HYBRIDS are available, but they are rather expensive. Here is a caller ID circuit that uses the Cermetek CH1845 DAA interface and the Sierra SC11211 caller ID chip.

1 2 3 4 5 6 7 8 9

18 17 16 15

TIP

RING

N/C

N/C

VINN

VCC

OHD

GND

N/C

RB RA RI

TERM

CH1845 DAA

1 2 3 4 5 6 7

14 13 12 11 10 9 8

VIN VIP EL1 EL2 EDC VRF GND

VCC CPM DO ED PD XOUT XIN

SC11211

Phone LineInputs

600Ω3.58 Mhz Xtal

+5V

+5V

nc

+

1µF0.1µF0.1µF 0.1µF

Rin

g I

np

ut

Te

rmin

ate

Ou

tpu

t

Off

Ho

ok

De

tect

Se

ria

l D

ata

Ou

tpu

t

En

erg

y D

ete

ct O

ut

downsizing very well. Silicon solar cells at a theoretical 26 percent are even less efficient. It seems that they can only accept "whole lumps" of quantum energy, and have to throw the rest away as heat. And, before Marks, any photosynthesis scheme was well under six percent efficient.

And efficiency is everything in solar power. On a good day, you haveone incoming kilowatt per square meter to work with. Say a nickel an hour "avoided cost" income for a perfect conversion. Or two cents a day allowing for night and weather. Naturally, your bottom line efficiencywill usually be much less than your theoretical. Let your efficiency drop too low and there’s no way that solar can be competitive. Get under the bottom-line efficiency of seven percent or so, and you will never be able to pay for your installation and land, owing to the time value of money. The longer it runs, the more it costs you for the financing.

But, alternatively, the nickel-perkilowatt-hour incoming solar energy on a 2200 square foot house roof adds up to over $3000 a year. Which is lots more than usually gets used underneath as electricity. So efficient solar electric conversion could completely blow away coal, nuclear, and even most hydro.

Marks has developed two different

solar to electric systems that seem to have high theoretical efficiencies.

Radio waves are electromagnetic. Solar energy is electromagnetic. The main difference between orange light (at 600 nanometers) and television channel two (6 meters) is a 10,000:1 size factor. Those light wavelengths may seem tiny, but we are starting to routinely handle submicron distances in integrated circuit manufacturing.

There’s this thing called a cyrstal set that you might have heard of. Just shove some electromagnetic energy into an antenna, rectify it somehow, and out comes dc power. These days, we call the same thing a rectenna. So why not use light waves instead of radio waves?

An antenna is any subsystem for converting radiated electromagnetic energy into conducted wire electromagnetic energy. Or vice versa. As a transmitter, if your antenna is now properly matched to the rest of your circuit, nearly all of your input energywill get radiated. And, since most antennas are linear and reciprocal devices, if you input any electromagnetic energy well inside of the antenna’s effective area, nearly all of it will get converted into conducted electricity. So, a properly matched antenna can be 100 percent efficient. And a rectifier nearly so.

Now, an optical antenna is trivial.

Just make it any old color so long as it is black. Even a black felt tip pen will do. The trick lies in rectifying and gathering all the received solar electromagnetic electricity, rather than burning it up as heat.

The Lepcon panel is the older of Marks’ two new developments. In a Lepcon panel, tiny rectenna elements are created on glass using more or less conventional but very advanced microlithography. These are basicallya conductive channel ending with a metal barrier diode. The photons in the incoming solar energy are used to accelerate electrons, which jump the barrier diode to become a dc current. Unlike a traditional solar cell, there are no "whole lumps only" quantum effects involved, and nearly all of the available energy gets converted.

The antenna/rectifier combination only works with one polarization of light. It converts the one polarization with up to a theoretical 80 percent efficiency, and passes the remainder on through. You could put a second Lumeloid panel underneath that is oriented 90 degrees from the first to convert the other polarization.

Or, you could use a sneaky trick consisting of a quarter wave plate and a mirror to rotate your rejected polarization by 90 degrees and shove it back up through the original film. Your combined efficiency ends up around a theoretical 72 percent.

The projected costs of the Lepcon process is around $250 per panel, and the panels should last 25 years.

The Lumeloid film process uses chemicals instead of very expensive microlithography. The chemical tech-niques in theory lend themselves to low cost and high volume production.The chemicals attempt to mimic the first half of the long photosynthesis process. A rather long chain carbon molecule, such as polyacetylene, is attached to some electron donor- acceptor complex, such as porphyrin and quinone.

The long chain molecule acts as a conductive antenna, changing the input optical energy into electron energy. The tunneling gap effect between the large donor and small acceptor rings acts as a rectifying diode for DC conversion.

For all this to work, the molecules have to be carefully oriented while

49.5

January, 1992

LUMELOID AND LEPCON SOLAR RESOURCES

Key Patents: #4,445,050 - Device for Conversion of Light Power into Electric Power.#4,574,161 - An ordered Dipolar Light-Electric Power Converter.

Key Paper:

Lumeloid Solar Plastic Film and Lepcon Submicron Dipolar Antennaeon Glass. 1990 International New Energy Technology Symposium.pages 201-210. From Planetary Association for Clean Energy below.

Key Info Packet:

From Advanced Research Development below.

Key Players:

Advanced Research Devel.359R Main StreetAthol, MA 01331(508) 249-4696

Dialog3460 Hillview AvenuePalo Alto, CA 94304(415) 858-2700

Electric Power Research Inst.PO Box 10412Palo Alto, CA 94303(415) 855-2000

Home PowerPO Box 130Hornbrook, CA 96044(916) 475-3179

Planetary Assoc Clean Energy191 Promenade du portage, #600Hull PQ, CANADA J8X 2K6(819) 777-9696

UMI300 North Zeeb RoadAnn Arbor, MI 48106(800) 521-3044

the sheet is being created. Mark’s work has centered on suitable bulk processes to do the orientation in a low cost and high volume process. Projected costs are five dollars per meter and three cents per watt.

At present, the Lumeloid films are only expected to last a year in strong sunlight. Once again, Lepcon panels use conventional microlithography onglass, while Lumeloid use oriented films that mimic photosynthesis.

Interesting, the Lumeloid process is totally reversible. You can input electricity and get light out as well. Which could lead to new lighting and display technologies.

For any of this to become real, we will need working prototype panels, credible third party research, and the proper peer review. My "usual sus- pects" of Science, Nature, Science News, and the technology page of the Wall Street Journal have been sus- piciously silent to date.

My own feelings are that short and open circuits in production panels are going to lead to the very same type of yield problems that have held back and restricted development of large area flat panel tv displays.

Because of the lack of even lab prototypes, their efficiency and cost projections at this time would appear totally meaningless. Although having a high theoretical efficiency sure doeshelp. But time will tell.

Caller ID Update

Time sure does fly when you are having fun. As a result, I’ve gotten hopelessly far behind on a bunch of potentially great projects here. So my caller ID project may take a while longer. Meanwhile, I’d thought we’d bring you up to date on what’s now coming down on caller ID.

Caller ID should be available in most parts of the country very soon. The controversy is dying down, since the benefits so totally and ludicrouslyoutweigh any potential problems. To see what dozens of others are now thinking about caller ID, you might want to check #2239 CALLERID.CAP on the GEnie RADIO RoundTable.

If for no other use, the convenienceof having a no-charge, no-hassle list of everyone that called you while youwere out is just flat out wonderful. There’s even an asterisk beside any

caller antsy enough to call twice.Motorola has just announced a

brand new MC145447 caller ID chip. Free sample kits are available. This one is supposed to include internal ring detection. But, as near as I can tell so far, the chip of choice remains the Sierra SC11211.

A FCC Part 68 interface is shown to you in figure four. Which is what normally has to go between you and the phone company. Key points include an exceptionally well balanced transformer with a 1500 volt isolation capability. While such an interface is fairly cheap and simple, getting the needed approval is not.

Several companies now offer some ready-to-go Part 68 interfaces. These are priced well above what you could build your own for. But they come pre-approved, eliminating most legal hassles. Dallas Semiconductor and Cermetek are two typical sources. An interface between the new Cermetek CH1845 and the Sierra SC11211 callerID chip is shown in figure five.

Both Cermetek and Sierra have lotsof free caller ID ap notes available.

As we’ve seen before, a number of ready-to-use caller ID products are available from Hello Direct.

New Tech Lit

From Sony, a new Laser Diode Guidebook. And from Hughes, a free brochure on their Nonvolatile Serial Programmable Devices. These gems include digital sinewave or code generators, electrically variable resistors or capacitors, switches, and counters.

The Best of Analog Dialogue is a three decade compilation of the very best in analog linear integrated circuitdesign info. From Analog Devices.

In a startling development, real thermography is now available for toner-based desktop publishing. One new source is Bennet LaserBrite. Youspray on chemical A to soften your toner, dust on powder B, and then apply heat from desklamp C. Presto. Instant raised letters. Even Braille.

Free stuff this month: A video on a high end printed circuit prototyping system from Direct Imaging. A free video on the Toaster, the low cost broadcast quality video production system from NewTek. And a great new sample A-42 plastic electronic case from Serpac.

A reminder that I do have a full collection of reprints available. Just give call me for more details.

49.6

Hardware Hacker

Don Lancaster’s

Hardware HackerFebruary, 1992

Using the IC masterWavelets info updateAnother Caller ID chipPiano & organ resourcesMusical note frequencies

50.1

Fig. 1 – THIS CALLER ID CIRCUIT uses the brand new Motorola MC145447. Features do include internal ring detection and data header stripping. Free samples are available. The service has to be available from your local phone company before this chip can be used.

1 2 3 4 5 6 7 8

16 15 14 13 12 11 10 9

TIP RNG RD1 RD2 NC RT PWR GND

+5V CDO RDO CD RD CSL XIN XOUT

MC145447

TIP in

RING in

500 pf

500 pf 10K

10K

+5V

+5V+5V

+5V

30 pf

30 pf3.58 Mhz

10 Meg

22 K

2200 pf

Coo

ked

Dat

a O

ut

Raw

Dat

a O

ut

Car

rier

Det

ect

Rin

g D

etec

t

Several commercial products are starting to appear using that great Rohm BA-1404 FM stereo transmitter circuit. In

particular, do check out the Pioneer CD-FM-1 and that Sony XA7A CD to auto radio adaptors. Dealer cost is in the $42 range.

What these do is let you play the output of a CD player through your existing car radio and audio system. The stereo channels are accepted by the BA-1404 IC and converted to a miniature but quite high quality FM "broadcast" signal. You unplug your antenna, plug in your adaptor, and then plug the antenna back into the adaptor. Presto. Your CD audio now appears on the FM dial as your choiceof one of two pushbutton-selected low end channels.

As we have found out in the past, sloppily breadboarded BA-1404 chips tend to drift and mistune enough that they are unacceptable to most of the newer synthesized FM receivers that demand perfectly on-channel signals. While the ultimate way to stabilize a FM transmitter is using a frequency lock loop against a crystal reference, Pioneer and Sony both seem to have gone a simpler route.

I will present more on these two beasties after I get a chance to test them. Either one of them should hack beautifully into a FM stereo wireless broadcaster circuit.

Wavelets Update

We’ve had bunches of requests for lots more wavelet info. So, here is a summary of where we seem to be…

Wavelets are a stunning new set of math tools that are strongly impactingjust about every region of advanced scientific study. While the keenest interest in wavelets now lies in video compression, wavelets are getting applied to everything from cardiologyto seismology to animal vision, and literally everything in between.

Wavelets are a newer method of analyzing any complex set of signals and extracting useful information from those signals. Unlike the ancient

Fourier Transform, wavelets have both global and local properties that let you selectively zoom in on signal portions of interest. For instance, good old Fourier is quite superb at working with the top and the bottom of a square wave. But the sides give itfits. Instead of Fourier’s "one-size- fits-all", wavelets let you apply lots of detail only where needed.

Wavelets tend to work in a "log" manner rather than in that "linear" fashion of Fourier. Which lets you pick up any fine details when wanted.Wavelets are also great at doing the "big lumps first". This gets handy in decompressing pictures, where your crude (but complete) picture initially appears and detail later gets added. It also gives you the ability to select the amount of needed detail on the fly.

One detailed book on wavelets is Wavelets and their Applications, as published by Jones and Bartlett. The topics thoroughly covered do include wavelet fundamentals, video com-

pression, digital signal processing, numeric analysis, and a bunch of advanced subjects. Sadly, the volume is written by math freaks for math freaks. It tends to run roughshod over any mere mortals. But it is there and certainly is the precise center of the emerging wavelet universe.

One tad less formidable wavelet summary tutorial and bibliography appears in that IEEE-SP (Signal Processing) magazine for October 1991 on pages 14-38. Note that there are dozens of different monthly IEEE publications. Make sure you get the right one.

For a useful collection of freebie reprints on wavelets for video compression, hardware chips, and design software, contact the folks at Aware. Wavelets do video compression far simpler, far faster, and with far fewer artifacts than the older (and now largely obsolete) DCT compression transforms. Their hardware is also farcleaner and more standard.

50.2

Hardware Hacker

Fig. 2 – THE STANDARD FREQUENCIES of the Western 12-note equally tempered music scale. Applies to most electronic and conventional musical instruments EXCEPT the piano. The piano keyboards must be "stretched" because of a piano’s non-harmonic overtones.

30.86829.13527.50025.957

24.50023.12521.82720.602

19.44518.35417.32416.352

61.73558.27055.00051.913

48.99946.24943.65441.203

38.89136.70834.64832.703

123.47116.54110.00103.83

97.99992.49987.30782.407

77.78273.41669.29665.406

246.94233.08220.00207.65

196.00185.00174.61164.81

155.56146.83138.59130.81

493.88466.16440.00415.30

392.00369.99349.23329.63

311.13293.66277.18261.63

987.77932.33880.00830.61

783.99739.99698.46659.26

622.25587.33554.37523.25

1975.51864.71760.01661.2

1568.01480.01396.91318.5

1244.51174.71108.71046.5

3951.13729.33520.03322.4

3136.02960.02793.82637.0

2489.02349.32217.52093.0

7902.17458.67040.06644.9

6271.95919.95587.75274.0

4978.04698.64434.94186.0

BA#AG#

GF#FE

D#DC#C

octave0

octave1

octave2

octave3

octave4

octave5

octave6

octave7

octave8

Fig. 3 – THE EQUALLY TEMPEREDnotes are all irrational, so only this single "magic" 8-bit sequence of division ratios can be a good enoughapproximation.

The 12 equally tempered musical keys repeat each OCTAVE, or 2:1 frequency interval.

This means each note is related to its neighbor by a geometric ratio of the 12th root of two, or 1.05946:1

Only this "magic" sequence of 8-bit divisors is good enough to let all of the notes sound good together…

232 219 207 195 184 174 164 155 146 138 130 123 116

Here is the better 9-bit "magic" sequence used by the MK50240…

478 451 426 402 379 358 338 319 301 284 268 253 239

Finally, I have posted some great IBM wavelet shareware on my GEnie PSRT as the file #365 WAVELET.PAK.You can call (800) 638-9636 for your connect info.

A New Caller ID Circuit

Motorola has just introduced an exciting new phone caller identi- fication chip called the MC145447. Free samples are available. They also have a very convenient but somewhat

overpriced $100 evaluation kit breadboard that gives you a full telephone to computer serial interface.

Figure one shows one of many possible circuits. This one is intendedfor continuous powering.

Compared to the earlier chips, the MC145447 includes an internal ring detection and apparently can be used without an expensive coupling transformer. It optionally strips that id header off and provides only "real" message bits. That’s the difference between their raw data output (the entire caller id byte sequence) and thecooked data (only the useful bytes) message strings.

Note that those two 500 pf input capacitors must be closely matched and rated to at least 1500 volts. A varistor and the normal part 68 interface should precede this circuit. The output levels are TTL or CMOS compatible, but have to get suitably translated to go over a RS-232 serial cable or data line.

The crystal used is a standard colorburst frequency available for under a dollar through several of our Radio- Electronics advertisers.

Naturally, your caller ID service must be already provided by your phone company before either the chipor the evaluation kit will work. If the service is not yet available, suitable

machine language emulation softwarecan be easily written for nearly any computer. The game paddle port on an Apple IIe is absolutely ideal as a fake source of id coding signals.

We’ll be seeing much more on this chip and suitable emulation software after I get a better chance to more thoroughly test it. The obvious thing to do is to "steal" enough power off a computer’s RS232 interface lines to eliminate any need for a stand-alone power supply. Internal power-down features of this MC145447 can greatlysimplify this task.

Stay tuned for more details.

The IC Master

Finding out just who makes an integrated circuit from just the part number can be tricky. Especially if you are mistakenly reading the date code instead. As you have probably found out on your own, Radio Shack has a quite useful Semiconductor Ref-erence Guide available for $4.

We’ve already seen how the two leading sources of service, repair, andreplacement semiconductors are NTE and ECG. Parts and training specific to RCA and GE products are also available through Thomson ConsumerElectronics Publications. This is an extension of the old "SK" series of replacement parts.

But the place to go for information on integrated circuits part numbers and cross references is a three volumeset known as the IC Master which is published by those Hearst Business Communications folks. The set is not cheap – it costs $160.

Hearst also does publish the fine Electronic Products trade journal, plus their EEM Master directories. These are usually free to qualified subscribers. But note that the EEM Master and their IC Master are two totally different and separate sets of references.

Top Octave Generators

This topic is more in the realm of "whatever did happen to…" than anything else. But we still get lots of helpline calls concerning top octave generators, especially in the Mostek MK50240 family. The bottom line: These are long out of date. They also have recently become impossibly difficult to get.

50.3

February, 1992

Fig. 4 – TOP OCTAVE GENERATOR integrated circuits produce all the needed notes of the musical scale. Input or output lines can be binarily dividedfor lower octaves. Sadly, these chips are getting hard to find.

1 2 3 4 5 6 7 8

16 15 14 13 12 11 10 9

+12 IN GND C#7 D7 D#7 E7 F7

C7 C8 B7 A#7 A7 G#7 G7 F#7

MK50240

C C# D D# E F F# G G# A A# B C

2.00240 MhzCLOCKINPUT

+12V

Inputs and outputs are 12 volt square waves

OUTPUT TONES

The traditional western musical scale is based upon twelve equally tempered notes per octave. An octave is a 2:1 frequency interval. Each individual note gets related by the twelfth root of two, or 1.059, times the frequency of its neighbor.

The notes, of course, are lettered asC, C#, D, D#, E, F, F#, G, G#, A, A#, B, and back around to the next C one octave higher. The traditional organ people number the octaves from zero up through eight. The usual "standardpitch" frequency reference sets note A4 to precisely 440.0 Hertz.

The usual twelve-note-per-octave equally tempered frequencies appear in figure two.

Because all of these music note frequencies are irrational, they have to be approximated. One way to do this is to take a high frequency clock and divide it down by magic numbers which can hit the needed accuracy. Musicians define the interval betweennotes as one semitone, and further define one percent of a semitone as a cent. A one cent frequency error is approximately 0.06 percent.

Reasonably trained individuals usually can spot a three cent frequency error, while the best of professional musicians can resolve a single cent. Thus, the relative frequency accuracyof all the notes should be better than 0.06 percent.

To get all of the notes to sound good together, well chosen "magic" division ratios must be used. Figure three shows some detail. Of all the possible 8-Bit divisor values, only the unique sequence of 116 123 ... 232 is good enough for a three cent worst case accuracy. If you have more bits available, then other sequences are also usable.

Figure four shows you how a top octave generator works. This is an oldN-channel integrated circuit that runs on a single 12 volt supply. An input clocking of 2.000240 Megahertz is required. This clock can come from a crystal for an absolute reference, or else can be variable for pitch blendingor for keyboard stretching variations. Thirteen outputs are provided, giving you all the notes of the highest octaveplus a spare C an octave lower.

To generate lower notes, you can either divide down the input clock fora single octave, or else add output

dividers to generate the entire music keyboard as shown in figure five.

Hackers have long ago found lots of other exciting uses for top octave generators. These include musician’s pitch references, piano tuning aides, meditation and musical toys.

Perhaps one of the most off-the- wall new-age uses did involve John Simonton’s chord egg. Polyphonic chords gotten from a lowered pitch top octave generator were chosen at random and routed to a stereo head- set. By suitable delay and phasing techniques, the apparent source of thestereo sounds is forced between your ears, and the chords literally bounce around inside your head. A few chordeggs remain available through PAIA electronics.

Assembly details on a traditional top-octave generator music module system appeared long ago in the June 1976 issue of Popular Electronics.

There are several reasons why the top octave generators are no longer popular. The "locked in" nature of octave-shifted notes sound as a singlericher tone, rather than as a separate pair of chorused voices. Having all the notes sounding all the time in the background can lead you to serious system noise problems. Zillions of wires are needed since the keyboard is usually non-scanned. The envelope and voicing opportunities are also severely limited.

But the main reason is that MIDI-based and all-digital sampled synthesizers do so much of a better job in a

far cheaper, a far simpler, and far cleaner system architecture. Besides being infinitely more flexible and sounding much better.

At any rate, new sources of top octave generators seem to be long gone. A very few of the original chipsmay remain available through PAIA or Devtronix on a catch-as-catch-can basis. It should also be possible to fake the top octave generators with programmable gate array devices. The FPGA costs are dropping rapidly enough to make this possible.

Do note that any pitch reference must be a nearly pure sinewave. Any higher harmonics will fool the ear andcause potential tuning problems.

Finally, if you know of any secret stashes of this one time great chip, be sure to let us know.

Piano and Organ Resources

I thought I’d gather together some traditional music names and numbers for this month’s resource sidebar. Theleading source for most piano tuning materials and supplies is at Tuner’s Supply, while the best source for antique instrument parts and data is the Player Piano Company. And a good horse’s mouth book is Piano Tuning and Allied Arts.

But do note that piano tuning is (1) A lot harder than it appears; (2) A miniscule, unprofitable, and rapidly declining market; and (3) an easy wayto cause irreparable damage.

Note also that most piano keys are never tuned to all their "correct" fre-

50.4

Hardware Hacker

Fig. 5 – A TRADITIONAL ELECTRONIC ORGAN architecture using top octave generators and dividers. Today’s MIDI-based sampled synthesizer circuits produce far better sound simpler and in infinitely wider variety.

filters

÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2

÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2 ÷2

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

keyer

TOP OCTAVEGENERATOR

Tolower

octaves

Fromlower

octaves

Audiooutput

B7

A#7

A7

G#7

G7

F#7

F7

E7

D#7

D7

C#7

C7

B6

A#6

A6

G#6

G6

F#6

F6

E6

D#6

D6

C#6

C6

PIANO & ORGANRESOURCES

Devtronix6101 Warehouse WaySacramento, CA 95826(916) 381-6203

Jrnl Audio Engineering Soc60 East 42nd Street, Rm 2520New York City, NY 10165(212) 661-2355

MIX Bookshelf6400 Hollis Street, Ste 12 Emeryville, CA 94608(800) 233-9604

PAIA Electronics3200 Teakwood LaneEdmond, OK 73013(405) 340-6300

Player Piano Company704 East DouglasWichita, KS 67202(316) 263-3241

Tuners Supply88-94 Wheatland StreetSomerville, MA 02145(800) 247-0702

quencies. Instead, the keyboard has tobe "stretched" to allow for the non- harmonic nature of real world string overtones. And that it takes several weeks to properly tune a piano.

One classic kit organ company is Devtronix, while PAIA offers a wide range of traditional to new age kits.

An excellent source for electronic music titles is the MIX Bookshelf, stocked by the folks that also publish the Electronic Musician magazine. Fundamental synthesizer secrets can often show up first in the Journal of the Audio Engineering Society.

Some additional electronic music

resources do appear in my Hardware Hacker II reprints.

New Tech Lit

A great "gottahave" Video Data Handbook from Signetics Philips thatis chock full of digital video interfacechips, RGB digitizers, multi-media chips, sync strippers, color decoding, and the usual A/D and D/A conversionchips and circuits.

Speaking of multimedia, the MediaMagic people do offer a Computers inScience and Art catalog full of good books, tapes, and software.

A free bibliography of papers on

microwave plasma applications is offered by Astex.

From Antique Electronic Supply, a 1992 wholesale catalog of supplies, books, tubes, info, and parts for the electronic collector. We’ve had lots of calls from experimenters trying to find Fahnstock clips in this day and age. These folks are one of the few remaining suppliers.

Another trade journal on magnetic and electric shielding ideas is EMC Technology. And a wide selection of aircraft hacker books is available by way of Aircraft Designs.

This month’s freebie mechanical samples include foams, films, and foils from ARclad, a Foam Specifier Kit from Voltek, and some self-stick bumpers from ITW/Fastex.

A reminder that I have recently revised my Incredible Secret Money Machine II and now do have autographed copies on hand for you when you call or write. You can get the ISMM by itself or as a portion of my Lancaster Classics Library.

You can also reach me via GEnie PSRT (800) 638-9636 where you will find hundreds of downloadable files and tutorials on hardware hacking and midnight engineering topics.

Let’s hear from you

Don Lancaster’s

Hardware HackerMarch, 1992

Laser printing repairsSync separator circuitGPS navigation updateVideo interface moduleHacking Super Nintendo

51.1

Fig. 1 – THIS COMBINATION SYNC STRIPPER and universal video interfacecan solve a lot of problems for you, including Super-Nitendo-to-anything interfacing, video overlay, and scope TV frame locking. Kits, fully tested units, and custom cable assemblies are available through Redmond Cable.

1 2 3 4

8 7 6 5

CS VIN VER GND

+5V ODD RC BUR

1 2 3 4 5 6 7 8

16 15 14 13 12 11 10 9

+ + +

LM1881 MC14049

RED-

BLUE-

GREEN-

GREEN+

BLUE+

RED+

+ 5VDC

CVID

GND

ENBL1

ODD

BURST

GND

LOAD

/ SYNC

SYNC

GND

VERT

680K0.1µF

0.1µF0.1µF

220µF/6v(x3)

0.1µF

75Ω

4.7K

We will start out with our usual reminder that this isyour column and you can get lots of technical help,

off-the-wall networking, plus consultant referrals per the box below. Your best calling times are from 8-5 weekdays, mountain standard time.

But please, before you call, make sure that the answer isn’t already in the text or in the Names and Numbersor in our occasional special resource sidebars. And please have a pencil or pen handy. I just cannot believe the number of calls I get that either refuseto look at or can’t find the sidebars.

I am also greatly expanding our informal PostScript Hardware Hack- ing Consultants Network. Send me a letter or give me a call if you wish to participate.

We also do have special Hardware Hacker and Midnight Engineering topics up on GEnie PSRT. You could reach me via [SYNERGETICS] email here to get the preprints, reprints, tutorials, and other great downloads in our ongoing experiment in electronic on-demand publishing. Plus, receive late breaking news (especiallyon PostScript, solar energy, and callerID) literally as it happens.

We do have lots this month on the Super Nintendo interface. But first…

A GPS Update

We sure had strong reader interest in our GPS navigation story from two columns back, so here is a quickie update:

That GPS, (for Global Positioning Satellite system) is a flock of roving satellites which do broadcast spread spectrum codes on 1227.6 and 1575.2 Megahertz. By receiving these signalsand digitally processing them, you can obtain your exact position and speed anywhere in the world. To an absolute accuracy of a hundred feet orso, and a potential relative accuracy of an inch or less. Thus GPS can be used for long distance navigation and for accurate surveying.

The horse’s mouth key paper you need is known as the ICD-GPS-200

document and is obtainable at no charge to US citizens through Space Systems Division/MZEE. You must send them a letter stating your name and purpose.

A great $12 Dan Doberstein reprint titled A GPS Data Receiver is newly available through DKD Instruments. This includes an excellent tutorial on GPS, full construction details on his ham radio style GPS receiver, and an extensive bibliography. The receiver is both data-only and an older analog design. While specifically designed with hardware hacking in mind, this receiver is definitely not a "shake the box" project. You’ll need microwave,digital logic, rf design, and software skills to sucessfully complete it. Yourcosts are also likely to be very much higher than by using a modern digital chip set as well.

Good nav technical papers often doappear in the Journal of the Institute of Navigation. These folks also have a new three volume GPS Resource File available for $50.

The prices of the commercial GPS

receivers are literally in free fall, and I’d expect a $35 chip set and a $79.95 receiver within five years. Today’s best offer in a high quality receiver useful for trucking companies and such appears to be the GPS-1 from Loyola Enterprises. The current list price is $795 plus software.

Note that all the GPS signals are right on top of each other and deeply buried in background noise, so any old surplus microwave receiver tunedto the GPS frequencies will show you nothing useful at all. Special digital despreading circuits must get built into your receiver.

I’ll try to work up a tutorial on GPSin a future column. But I think I’d better first do some background stuff on the very fundamentals of digital correlation and spread spectrum com-munications. Whenever.

Video Sync Separation

Another popular helpline topic is video interface. And the number one ongoing request is for a simple and effective sync separator. The sync

51.2

Hardware Hacker

Fig. 2 – PRINTED CIRCUIT BOARD LAYOUT and overlay for the universal video interface. Accurate and camera-ready art is also available via GEnie PSRT as file HACKFG51.PS. PostScript downloads can easily eliminate all of your darkroom work.

ENBLODDBRSTGND

LOAD/ SYNCSYNCGNDVERT

RED-BLUE-GRN-GRN+BLUE+RED+

+5VDCGNDCVID

0 .1

680K 0.1

0.1

4.7K 75

0.1

LM1881 MC144049220u / 6v

UNIVERSAL SYNC & VIDEO INTERFACE

SYNERGETICS#332.2

separation process lets you take your normal composite video signals and extract those horizontal and vertical synchronizing pulses from it.

The most obvious use for a sync separation is to let you clearly view video signals on your oscilloscope. Without a field or frame reference, allyou will see is a blur. Other uses for sync separation do involve stripping closed captioning or other data off specific horizontal lines present during vertical retrace, grabbing stock quotes, inserting windows, pattern generators, title overlays, wiping and fades, color keying, and other special effects. Or simply adding a pair of crosshairs.

Figure one shows you a simple and low cost circuit I’ve worked up that can combine both an effective sync separator and a low cost universal video interface card. The key chip is the National LM1881 sync separator mini-dip. You take your usual one to two volt positive going sync=ground video signal and capacitor couple it topin 2. The chip extracts the compositevideo and produces the active low TTL/CMOS compatible composite sync output on pin 1.

Several other pins on the LM1881

provide other functions that you may find handy. Pin 3 gives you a vertical sync reference as one single pulse without the usual teeth or serrations. This is the one you will usually want to lock your scope to. Pin 5 is a burst gate that gives you a slightly delayed horizontal sync pulse that can be usedto extract any NTSC (Never The SameColor) chroma burst info.

An RC network found on pin 6 is intended to create a default vertical sync in absence of a true NTSC video input. This is handy for the "almost" NTSC common to the computers and video games. The time constant can be shortened for higher scan rates; seethe National data sheet for details.

Finally, pin 7 lets you pick out the odd and even fields of an interlaced NTSC frame. This output is active only when the input composite video has a full interlace. Advanced color editing is one possible use.

An external source of the usual fivevolts DC is needed. Since the current is only seven milliamperes, just aboutany old supply will do. As usual, keepthe power bypass caps real close to your chips.

Several other features on the circuitare handy for special video interface

cables. The three large capacitors let you couple red, blue, or green video off emitter follower outputs and then connect them to RGB monitors. A 75 ohm resistor is handy for terminating cables. And a logical high signal is useful for such things as enabling the sound on certain receiver/monitors.

By itself, the inverter is handy for converting active low sync into activehigh and vice versa. While most of the video systems do use active low sync, Commodore and one or two of the others may not.

The printed circuit layout is shown you in figure two. Empty boards, kits,tested circuits, and both stock and custom interface cables are available from Redmond Cable. You can call orwrite them for a current price list. I’ll also post this layout on GEnie PSRT, so you can easily create your own accurate version without needing any photo work. See HACKFG51.PS.

You may want to keep some empty or partially populated boards on hand to solve special cabling and interface uses. The large runaround ground on the outside is especially handy for shielded cable terminations.

For this month’s contest, just tell me about an unusual or off-the-wall use for a sync stripper circuit. There will be all of those usual Incredible Secret Money Machine II book prizes,along with an all expense paid (FOB Thatcher, AZ) tinaja quest for two going to the very best of all. As usual,send your written entries directly to me at Synergetics, rather than over to Radio-Electronics editorial.

Let’s hear from you.

Nintendo-to-Anything Interface

As figure three shows us, there’s a very interesting Multi-Out connector on the back of those Super Nintendo game machines. This gives you lots of alternate video and sound output formats that you might find handy.

For instance, you can go to a RGB monitor for sharper images and bettercolors. Or add total stereo sound or Super VHS improved resolution.

Or, you may want to hang any old tv-compatible color monitor plus a pair of headphones on the machine to silence kids and keep them off your main prime time television set.

Let us see exactly what is on this connector and how to use it. By a

51.3

March, 1992

Fig. 3 – THE SUPER NINTENDO MULTI-OUT REAR CONNECTOR has all sorts of useful video and audio options available. Here are the key details.

1 RED VIDEO

For linear RGB monitor use.One volt peak-to-peak off ofan emitter follower source.

Requires a series 200 µfdcoupling capacitor.

3 /RGB SYNC

For linear RGB monitor use.Active low combined verticaland horizontal sync pulses.

0 to 5 volt high logic source isCMOS and TTL compatable.

5 GROUND

A pair of ground pins is provided to ease terminatingof shielded video and audiocables.

7 SUPER VHS "Y"

The luminance channel for SuperVHS video appears on this line.

One volt peak to peak into a 75Ωload. Internally capacitor coupled.

9 NTSC VIDEO

Plain old NTSC composite videoappears on this line. The synctips are at ground.


11 L+R SOUND

The monophonic and stereomatrixed sum sound appears on this pin.

One volt peak is suitable foramplifiers but not headphones.

12 L-R SOUND

The stereo matrixed differencesignal appears on this pin.

Add pins 11 and 12 for leftstereo; subtract them for rightstereo output signals.

10 +5 VOLTS DC

A limited amount of +5 voltssupply power may be drawn outof this pin for sync inverters ordoing a stereo dematrixing.

Limit current to 50 milliamperesand use thorough bypassing.

8 SUPER VHS "C"

The chroma channel for SuperVHS video appears on this line.


6 GROUND

A pair of ground pins is provided to ease terminatingof shielded video and audiocables.

4 BLUE VIDEO



2 GREEN VIDEO



special arrangement with Redmond Cable, all the connectors, the above interface kit, and special and stock cable solutions for almost any Super Nintendo interface are available.

The Multi-out connector is really six-over-six edge traces on a double sided circuit board. Looking at the rear, the traces are odd numbered 1,3,5,7,9,11 on the top, going right to left. And the similar pins are even numbered 2,4,6,8,10,12 on the bottom,again going from right to left.

Both pins 7 and 8 are grounds. The pair make terminating several shielded wires much easier.

A +5 vdc output is provided on pin 10. It appears to be capable of drivingat least 50 milliamperes. But you shouldn’t suck the poor machine dry, and you should very carefully bypass and filter any use of this supply.

There are a pair of sound outputs. Pin 11 is your choice of monophonic sound or a (L + R) matrixed stereo. Note that "left" plus "right" equals "both". Pin 12 is (L - R) matrixed stereo. These signals are capacitor coupled and are the proper size for your usual audio inputs on a hi-fi receiver or computer monitor.

Note that some computer monitors have a sound capability and some do not. The easiest way to tell is to find an obvious volume control located somewhere on your set. No volume control, no sound. Other monitors may need a special pin activated to turn the sound off or on. We’ll see an example of this shortly.

All your sound cables should, of course, be shielded.

Sadly, the power levels are far too low to usefully drive a speaker or a pair of headphones. But Radio Shack has an interesting beastie which no Hardware Hacker should be without. It is their #227-1008C mini-amplifier and speaker. The (L + R) output easily drives this mini-amp, by way of a standard miniature phone plug.

This mini-amp solves the problem of a monitor that has no sound. You can also plug headphones into your mini-amp for any silent running. The mini-amp is powered by your choice of an internal alkaline 9 volt battery or by a plug-in 9 volt dc supply.

Because of the matrix used, you cannot get stereo directly off of pins 11 and 12. Instead, you have to add

the two signals together to get the leftchannel, and subtract the two signals from each other to pick up the right channel. Like so…

(L + R) + (L - R) = 2L(L + R) - (L - R) = 2R

A stereo dematrix can be done witha quad op-amp or a transformer and four resistors. In theory, you could make use of a CMOS biased inverter amplifier, but your common mode

supply noise rejection might suffer onyour right channel. More details on biased inverter amplifiers appear in my CMOS Cookbook.

Let me know if you need any more info on stereo matrix extraction.

There are three different types of video outputs found on the multi-out connector. Plain old grounded sync composite video appears on pin 9. This can be routed to any standard NTSC video input on a monitor, VCR

51.4

Hardware Hacker

Fig. 4 TYPICAL SUPER NINTENDO TO LINEAR RGB VIDEO MONITOR interface connections can give you sharper resolution and better colors.

+ 220

+ 220

+ 220

/SYNC

GND

GREEN

BLUE

RED

L + R

GND

SYNC

GND

GREEN

BLUE

RED

INTERNALAUDIO

(C) COMMODORE 1084 MONITOR

3

5

2

4

1

11

6

2

3

1

5

4

SU

PE

R

NIN

TE

ND

O

(mul

ti-ou

t 12

fem

ale

)

CO

MM

OD

OR

E

1084

(Lin

RG

B D

IN-5

mal

e)

4.7 K

+ 220

+ 220

+ 220

/SYNC

GND

GREEN

BLUE

RED

L + R

GND

+5VDC

RGND

BGND

GGND

/SYNC

GND

GREEN

BLUE

RED

AUDIO

SENBL1

SENBL2

(B) SONY KV1311CR RECEIVER/MONITOR

3

5

2

4

1

11

6

10

30

16

26

27

25

8

12

10

24

34

33

SU

PE

R

NIN

TE

ND

O

(mul

ti-ou

t 12

fem

ale

)

SO

NY

KV

1311

CR

(Am

p 1-

1023

97-5

34

pin

fem

ale

)

+ 220

+ 220

+ 220

/SYNC

GND

GREEN

BLUE

RED

L + R

GND

RGND

BGND

/SYNC

GGND

GREEN

BLUE

RED

(A) APPLE IIGS A2M6014 MONITOR

EXTERNALAUDIO

3

5

2

4

1

11

6

3

6

5

9

2

1

13

SU

PE

R

NIN

TE

ND

O

(mul

ti-ou

t 12

fem

ale

)

AP

PL

E I

IGS

A2M

6014

(DB

15 m

ale

)

or television set. Note that a direct video input will often have sharper images and better colors than does entry by way of some channel 3 or 4 modulator. Simply because far less electronics gets in the way and an RF modulation and demodulation can be eliminated.

Super VHS or Y-C video appears onpins 7 and 8 with that luminance "Y" output on pin 7 and the chrominance or "C" output on pin 8. These can be routed to any system which accepts Y-C video. Because of the separation of all the color information and the higher bandwidths, these Y-C outputs should look far better than regular composite video.

The best video of all, though, is available as a separate red (on pin 1), green (pin 2) and blue (pin 4) video. These red, blue, and green outputs do come off from emitter followers and have a strong dc bias. They must be capacitor coupled to your ultimate destination using a 220 microfarad or higher series capacitor on each line. Be certain to put the (+) side of the capacitor on the Nintendo end.

The needed RGB sync appears on a fourth active low line on pin 3. The active low sync is correct for Apple IIGS, Sony, and most "standard" RGB uses. It is the complement of what is needed for Commodore and certain others. The line swings ground to

+2.4, but is only weakly TTL compatible. More on this next month.

Note that some connector plugs do not have all of their pins available, especially for the RGB sync and VHS chroma. The Redmond plugs include all of the pins.

Several interface circuits appear in figure four. In each case, a partially populated figure one circuit can be used to greatly simplify your cables and interface.

In figure 4-A, you can connect RGBvideo to any Apple IIGS monitor by using the three serial video capacitorsand the right connector on each end of your cable. Since the IIGS monitor has no speaker, you have to use a hi-fior the Radio Shack mini-amp.

Figure 4-B, shows an interface to the older Sony KV1311-CR receiver/ monitor. Again, we have those three serial video capacitors. This time, we use an enabling resistor to turn on the internal sound and eliminate any needfor a companion amplifier.

The interface to the Commodore 1084 color monitor is shown in figure 4-C. As usual, the red, blue, and greenvideo have to be capacitor coupled to the appropriate pins on the LinRGB connector. This time, an active-high sync is needed rather than active-low,so the inverter must get added as shown. While the sound is internal, it has to be routed via a separate audio cable and phono plug that goes into the Audio input. The size and positionadjustments on the back may also need a slight readjustment.

Yes, we are working on VGA and multi-sync solutions. Stay tuned or check GEnie PSRT for availability.

Once again, some mix and match kits, all-pin connectors, parts, and cables are available from Redmond Cable. Do let me know which other interface circuits you would like to see worked out.

Laser Printer Repair Resources Where can you go to get training,

parts, and information on today’s laser printers? Many of the printer manufacturers are super secretive andgo far out of their way to prevent you from getting the parts and materials you need to best use your printer and to cheaply keep it alive. So, for this month’s resource sidebar, I thought we’d gather together some of the best

51.5

March, 1992

Fig. 5 – THESE HEWLETT-PACKARD LASER SERVICE MANUALS can be used for mechanical repairs on most of the printers shown here. While expensive, they are the best info available, and far easier to get than many of the others.

HP MANUAL

02686-90920(CX Engine)

33449-90906(SX Engine)

33459-90906(SX Engine)

33471-90904(LX Engine)

33491-90929(SI Engine)

HP PRINTER

LaserJet I

LaserJet IILaserJet III

LaserJet IIDLaserJet IIID

LaserJet IIP

LaserJet IIIsi

APPLE PRINTER

LaserWriterLaserWriter Plus

LaserWriter NTLaserWriter NTX

LaserWriter FLaserWriter G

– – – –

Personal LW NT

– – – –

QMS PRINTER

PS800

PS810 & TurboPS820 & Turbo

PS815-MRPS825-MR

– – – –

PS410

– – – –

LASER PRINTERREPAIR RESOURCES

Black LightningRR 1-87 Depot RoadHartland, VT 05048(800) BLACK99

GEnie401 North Washington StreetRockville, MD 20850(800) 638-9636

Hewlett-PackardPO Box 10301Palo Alto, CA 94303(415) 857-1501

Lazer Products12741 East Caley Ave #130Englewood, CO 80155(303) 792-5277

Recharger101 Granite St Suite FCorona, CA 91719(714) 359-8570

Don Thompson23072 Lake Center Dr #100El Toro, CA 92630(800) 457-5776

of the laser repair resources.The overwhelming majority of all

laser printers use Canon engines, so that is usually where you’ll want to start. Hewlett Packard has by far the best and the most available Canon manuals in the industry. And since a SX engine is a SX engine, those HP manuals are most useful on similar Apple, QMS, and lesser machines.

Figure five summarizes the key HP service manuals, along with some of the competing machines they cover. HP recently has sharply raised all of their service manual prices. Many are in the $100 range. Even at this price, they pay for themselves on their first use. They are essential gottahaves.

HP does also sell parts to anybody overnight via VISA and an 800 order line. Again sadly, individual parts arehard to get. They prefer to sell you an entire $50 fan instead of the 50 cent grommet which is the only thing that ever goes wrong with the fan.

The best place to go for individual parts is Don Thompson, who also nowoffers by far the finest of multi-level training and repair seminars in the entire industry.

My two favorite places for toner refilling supplies and materials are Arlin Shepard of Lazer Products, and Walt Jeffries and his crew at Black Lightning. The latter are also into the special toners for fabric printing and printed circuits as well.

Black Lightning also publishes TheFlash, a free and friendly newsletter crammed full of useful desktop info.

There are several laser printing andtoner recharging trade journals, but the only one of any consequence is Recharger. They are already up to several hundred pages per issue, and list dozens of suppliers for just about any laser printing repair need.

I do try to carry a lot of toner and laser printer repair stuff on our GEniePSRT. We also have on-line real time conferences with the leaders in this field. Both those upcoming and as bunches of downloadable transcripts. These files usually will start off with an "RTC" prefix.

New Tech Lit

From SGS/Thomson a new Modem Databook and Applications manual. From Benchmarq, a 1991 Databook on their energy management (power switching) chips for laptops, real timeclocks, and non-volatile memories.

A new and very thorough Heatsink Application Handbook is available from Aham Tor. TV satellite products and info are offered by AIS Satellite and Skyvision. Both do provide free catalogs. Skyvision has a very good satellite book selection.

Our two new trade journals for this month include Electronic Product Review on new component parts and CADalyst for those users of AutoCad

CAD/CAM systems.Those folks at Small Parts always

have been a great place to go for all the robotic and mechanical stuff your hardware store never heard of. As well as any precut plastic and metal shapes. They have recently moved to larger quarters, so you may want to note their new address and pick up a new and free catalog.

A free School Shop catalog from Rutland offers all the usual machine shop tools and supplies.

As per usual, most of the Names & Numbers are shown in the ending appendix, while the Piano & Organ Resources appear in their own sidebarshown above.

A no-charge sample of backlit fiberoptic displays is newly available fromSerigraph, while the Caplugs people offer a free sample idea kit on their plastic plugs, caps, and enclosures.

A reminder that I now do stock my Active Filter Cookbook for all of the fundamentals of quickly building up your own analog lowpass, bandpass, and highpass filter circuits. I’ve got autographed copies on hand for you here at Synergetics when you call or write. You can get this book by itself or as one portion of my Lancaster Classics Library.

51.6

Hardware Hacker

Don Lancaster’s

Hardware HackerMay, 1992

FM stereo broadcastersSuper Nintendo updateCD to car radio adaptorsDYS and other resourcesOckham’s razor revisited

52.1

Fig. 1 – THE SUPER NINTENDO RGB SYNC output only looks like it is TTL or CMOS compatible. Add the external resistor shown for a LSTTL interface.

3

5

680Ω10K

2.4 v

0.2 v

To LSTTL gateor RGB monitor

SYNC input

multi-out

2.4 vdc (?)

SUPER NINTENDO

5 3

Let’s start off with an update to those Nintendo interface circuits we looked into last month. For those of you who

came in late, you will find a special connector at the rear of the Super Nintendo machines that can let you connect up to stereo amplifiers, headphones, RGB monitors, Super VHS recorders, and bunches more.

We did look at this connector in some detail last month and we saw several useful and low cost interface circuits. And we found that Redmond Cable offers all sorts of custom and stock video game interface kits.

But after some further testing, the R—

G—

B—

—

S—

Y—

N—

C—

line on a Super Nintendo connector pin three is not quite what itappears to be. As figure one shows you, this pin looks like it should be both CMOS and TTL compatible, but itis not. You can’t pull it up fully for CMOS and there isn’t enough current sinking capability for much of TTL. Some (but not all) RGB monitors will refuse to lock to this output.

The problem is that the output does not come from a "real" logic gate. It apparently arrives from an emitter follower which has a weak pulldown resistor. And a low supply voltage.

There seem to be several simple workarounds you can try. The easiest is to add the external 680 ohm resistor shown. This should give you enough current sinking for typical LS TTL inputs. Use a scope to verify your levels. There is even a place on last month’s circuit board for the resistor.

Otherwise, you should be able to directly interface to any low cost but rare 74HCT CMOS logic. Or you can use the sync stripper circuit we saw last month as a substitute, deriving your sync from the composite NTSC video instead.

Finally, next month we might look at a simple sync amplifier which also will be needed for an upcoming new Neo-Geo interface. It should also workand is based on adding feedback to a 4049 inverter to make it into a simple ac amplifier.

So do stay tuned.

Ockham’s Razor

See, I even got the spelling correct. William of Ockham was a fourteenth century English philosopher. Para- phrased, Ockham’s really big thing in life was that "The simplest possible explanation is usually the best – and probably also the most correct." And Ockham’s Razor can be your ongoing process of slicing away and reducing everything to its bare (but still quite correct) essentials.

Very few engineering design courses ever mention Ockham. But hisrazor should be the very center of virtually all engineering design, all analysis, development, debugging, andrepair. So, I thought I’d use Ockham’s razor as an excuse to gather together and simplify the few loose helpline odds and ends that I’ve been meaning to comment on anyway…

Cold Fusion– Ockham says they had their chance to get their act together and they blew it. Yes, strange amounts of heat can apparently be produced in highly unusual lab circumstances. No, such rather mundane reasons as hydrogen fires, mixed gas fuel cells, or an embrittlement stress relief have not been totally ruled out. And no, I have not seen so much as one credible and reproducible shred ofevidence that anything atomic is in

fact coming down. Barring any new developments, cold fusion seems to beon hold. And probably remains a sucker bet for hackers at this time.

Pseudo Radio Astronomy– Several years back, a "radio astronomy" receiver appeared in RE that seemed to be responding to extragalactic signals in a circuit which was vastly simpler than those used by far more credible researchers. I’ve often been asked for my comments on this, so…

Ockham says the circuit was just a simple analog thermometer that was measuring the temperature drift of the offset voltage of a 741 op amp. When the sun set, so did the 741. And the circuit capacitors that mysteriously acquired charge are no mystery at all. The effect is known as bounceback and has to do with lateral charge migration in a dielectric.

Utility linemen do learn all about bounceback in lecture one of day one in lineman’s school. And there is a very simple way to spot any utility lineman who knows all about bounceback: They are the ones still alive.

Now, this circuit may or may not have in fact been receiving the extra- galatic signals. But the temperature drift and bounceback effects clearly would have been many millions to many billions of times larger. Thus there would be no way to tell until all

52.2

Hardware Hacker

Fig. 2 – MOST LOW END FM WIRELESS BROADCASTERS simply will no longer work, because nearly all the newer synthesized receivers now DEMAND precisely on-channel stations. The Pioneer CD-FM-1 (block diagram shown here) generates exact frequency stereo FM signals.

(L+R) (L-R)Stereo mux gen

IC1, X1

Preemphasisand driver

Q1, Q2

FM reactancemod/oscillator

D1, Q3, X2

Buffer andbandpass filter

Q4, BPF1

Changeoverrelay driver

Q7, D4

1.4 volt dcPost-regulator

Q8

SwitchablePre-regulator

Q5,Q6,IC2

Left audio input

Right audio input

+12 vdc input

Aux on/off input

From car antennaTo car radio

of these first order effects have been carefully and painstakingly removed from the circuit.

The Newman Motor– The Newman Motor is (or was) a perpetual motion machine that still seems to be ekeing out a meager existence on late night talk shows. This one-time media circus has been around for a decade or more. Yet, for some strange reason, working models still remain few and far between. Now, if we’re going to grant the true believers that something weird was in fact going on, then Ockham’s razor reduces it down to "sparks may lengthen battery life."

Which might bear further looking into as a hacker topic. An ordinary flashlight cell does not yield all of its chemical energy whenever it "runs down". Clearly, if so much as a tiny scrap of the zinc case remains, then recoverable chemical energy may still remain. At least in theory. Instead, a cell will polarize and thus raise its series resistance to the point where it can no longer deliver useful power.

What if you recycle a fraction of thepower back into the cell as a high current pulse? Say ten amps for ten milliseconds per second in for every continuous one amp out? Could this in fact partially delay the increase of cell resistance by slowing down the polarization process? Or maybe just

warm the cell up to a more optimum power delivery point?

Note that electroplaters do this all the time. They occasionally reverse their plating process and purposely unplate for a while. This improves the smoothness and does other good things to the finish.

The obvious things to ask here are "Does energy recycling help us at all?"and "What are the optimum recycling pulse strengths and best duty cycles?" "Does any higher frequency ac help?" And, of course, "Even if all of these effects do significantly improve life, are the economics there?"

Let’s have your thoughts on this. Cell energy recycling does look like a reasonable and legit research topic. But a warning: do keep your target carbon-zinc cells in a suitable "bomb shelter" such as a paint can full of sand. And do be careful.

Microcontrollers – The breakeven point between using and not using a CPU and RAM-ROM-I/O architecture in any Hacker project was passed a decade ago. Ockham says that it’s nowridiculously faster, cheaper, and far better to include the microprocessor these days, rather than foolishly trying to leave one out.

Yet I get all of these strange calls for projects that require such things as keyboards, displays, fancy timing,

strange sensors, and miniscule markets which could be done insanely faster and cheaper by (A) first making a model with a $30 Commodore 64 from a yard sale and then, if really needed, (B) working out a one or two chip RAM-ROM-I/O solution.

Besides lots of really great microcontroller projects found right here in Radio-Electronics, you’ll find lots of others over in Steve Ciracia’s Circuit Cellar Ink. And I do offer my Micro Cookbook I and Micro Cookbook II that can get you started on many of thefundamentals.

Wireless Broadcasters

One of the less pleasant hacker surprises recently is that most low costFM wireless broadcaster circuits flat out will no longer work. Older analog FM radios could get tuned anywhere across the entire band and had a very strong AFC or automatic frequency control circuit which would lock onto a non-standard signal and track it anywhere. But nearly all of today’s totally digitally synthesized FMre- ceivers (especially most car radios) absolutely demand the transmitted signal to be precisely locked onto one of the FM broadcast channels.

Designing any high quality FM transmitter that is both ultra stable and able to be rapidly and linearly frequency modulated gets tricky fast. Because you are asking for a circuit that both will and will not change its frequency. The "technically correct" high end solution is to use an indirect circuit known as the frequency lock loop. The average output frequency from your transmitter gets divided down using a counter and compared against a crystal reference. An error signal is then derived phase lock loop style and used with varactor diodes to continuously force your transmitter back onto the correct frequency.

Hams have long chosen a simpler technique called crystal pulling. Your average crystal is slightly sensitive to reactive loading in a circuit. The rule of thumb is that you can pull a plain old crystal around one-tenth percent. But crystal pulling is usually highly nonlinear. And limited in range.

To pick up enough deviation, hams would start off with a low frequency crystal and then multiply up into their final 145 Megahertz or whatever freq

52.3

May, 1992

Fig. 3 – APPROXIMATE SCHEMATIC of the Pioneer CD-FM-1. While intended as a CD audio to car radio adaptor, this module can easily become a highly stable and on-channel FM stereo wireless broadcaster. Applying +12 volts to the AUX input activates the module.

1 2 3 4 5 6 7 8 9

18 17 16 15 14 13 12 11 10

LIN AFB GND MOB XIN XOUT AMP GND OFB

RIN BAL BAL VCC XOUT CAR MOD REF OSC

IC1 BA14043

5

2

1

7

C23 0.001

RIGHTAUDIOINPUT

LEFT AUDIOINPUT

GROUND

LAMP

AUX

D3

D2 6VQ5

1 amp inline fuse

From 12 v battery

WARNING: Be sure to current limit the AUX input with an external 1K resistor!

12KR2

R112K

51KR6

51KR5

0.001C4

0.001C3

38 kHzX1

10 pfC9

nc

ncnc

0.001

C11 220pf

VR2 200Kpilot

10 µC6

C510 µ

+

+

2.7K

R7

10 µFC7

0.001C8

5.6KR4

0.001C2

5.6KR3

0.001C1

+

VR1 50KL-R balance

= from +1.4 volt regulated supply Q8

noisefilterC27

22R27

C30 33 µ

+

R28

Q6

1KR26

2.2KR25

in g nd

o ut

IC22v reg

+1.4 vdc(source)

Q8

.22 µC24

100 µC25

220 µC29

+ +

+

4.7KR24

2.2KR22

1KR23

.22 µC24

Q7

RY1

D4

from antenna

to car radio+12v

C12 20 µ

+

Q2

100R11

Q1

100R10

1KR9

2.2KR8

C13

C14

TC1hf pre-

emphasis

1500R12

10 µHL1

varactorpair D1

.001C15

X289.1 Mhz

2.2 µHL3

1.5 µHL3

2.2 µHL3

0.001C18

0.001C22

1KR14

1.5KR13

220R16

1KR18

1KR17

1

2

4

3

BPF1

89.1MHz

Q4C6 TC2

Q3osc adjust

C17.001C19

C22

330R20

100R21

1KR19

range. Typical hams rarely concern themselves with any wide deviation broadcast quality audio. In fact, they are not allowed to do so.

Apparently both Sony and Pioneer have figured out how to linearly pull a special third overtone HF crystal to directly let you do a full CD quality FM stereo transmitter that is precisely locked onto your correct frequency. Sony’s product is called the XA-7A, and Pioneer’s is the CD-FM-1. While the intended use of these units is to let you conveniently add a CD stereo player to your car radio, either one will apparently make up most of the critical circuitry for an excellent and very high quality FM stereo wireless broadcaster. Dealer cost of these is in the $42 range, and they seem to be fastand fun to hack. And offer both on- channel locking and near-broadcast quality. We will look at the Pioneer CD-FM-1 here.

Obvious uses for a short range FM broadcaster include "Please buy my house" messages for drivebys; baby sitting or handicapped monitoring; andcord-free audio for a teacher, a public speaker or a video actor. But there’s also zillions of non-obvious uses, including such things as getting data onto or off of a rotating shaft and shortrange rocket telemetry.

Limited range and limited power FM broadcasters are now generally allowed by the FCC, while the more powerful units have to meet specific licensing and certain type approval requirements. More details on getting and meeting FCC specs appear in our Hardware Hacker III reprints. Both ofthe unmodified Sony and Pioneer unitsseem to have been created with full FCC compliance in mind.

I could also see several wired or semi-wireless broadcaster aps that might use a twin lead to route high quality audio all over your plant or whereever. Using wires, you could easily go several hundred feet without running afoul of FCC specs. All the while avoiding the hum and noise problems of using "real" audio. And a whole new world of point-of-sight light modulated FM data links is also newly opened up.

In their intended use, you unplug your car radio antenna, plug in the CD-FM-1, and then reconnect your antenna. A DIN-8 connector goes to

your CD player, and the usual red wireto your +12 volt battery.

When your CD gets turned on, its audio appears at 88.1 on your FM dial. All other stations are muted. Which

quickly and conveniently can let you use your existing car audio system without needing anything fancy in the way of rework or switches.

A block diagram of this matchbox

52.4

Hardware Hacker

Fig. 4 – SIMPLIFIED SCHEMATIC of the linear reactance modulator.

TANK B resonates BELOW thecrystal’s frequency and appears

as a high CAPACITIVE reactance.

TANK A resonates ABOVE thecrystal’s frequency and appears

as a high INDUCTIVE reactance.

The third overtone PARALLELRESONANCE of the crystal is at

the desired FM channel frequency.

The final TOTAL IMPEDANCE of theentire circuit appears as a very high RESISTANCE at the instantaneousfrequency set by the crystal and bythe present audio modulation value.

The AUDIO MODULATION usesa pair of VARACTOR DIODESto vary these capacitors.

sized module appears in figure two, while an approximate and unofficial schematic is shown in figure three. Because of the surface mount parts used, certain component values are only my estimates. The exact circuit shown also may not be fully accurate.

At first glance, this circuit seems deceptively simple. But if you flip the board over, you’ll find nearly a dozen more surface mount semiconductors on your foil side. It is obvious that bunches of time and effort went into the design.

As with any circuit, you’ll usually want to start off with your power distribution. The twelve volts from thecar battery gets turned off and on by an AUX logic signal. The power is only applied when your CD is to be used. The power switching is via inputswitching field effect transistor Q5 andseries power driver Q6. Q6 is followedby a two volt regulator IC2 that in turn is followed by the dynamic regulator or capacitance multiplier at Q8. The post-regulator will obviously introduce a temperature drift that may or may not be intentional.

Several refinements in the supply switching include zener D2 to prevent any turn-on at all with a weak battery or during cranking; and the network R27-C30 gives a slight turnoff delay toeliminate clicks or thumps.

Except for that switchover relay, theentire rest of the circuit runs on the dynamically regulated 1.4 volt supply. Theoretically, one single AA cell

could be used instead.The heart of the circuit is the great

Rohm BA-1404 FM stereo broadcaster chip which we have looked at in the Hardware Hacker II reprints. Only this time, the internal RF transmitter circuitry is not used and gets very carefully deactivated. Left and right audio are combined into the L+R baseband and L-R subcarrier set by that 38 kilohertz X1 crystal pilot 2X reference. Control VR1 adjusts your balance and VR2 sets the 19 kilohertz pilot level.

The multiplexed audio output is resistively added to the pilot and gets routed to a combination driver and preemphasis network using Q1 and Q2. The amount of high frequency preemphasis is adjusted by TC1.

The linear and broadband "crystal puller" is an interesting reactance modulator scheme using a pair of varactor diodes at D1. A simplified circuit of the modulator appears in figure four. What you’ve got is a crystal put in series with the parallel resonant circuit "A" in turn in series with a second resonant circuit "B".

Tank "A" is tuned well below the crystal’s parallel resonance and will normally appear as a high inductive reactance. Tank "B" is tuned above thecrystal parallel resonance and should appear as a capacitive reactance. In absence of any audio modulation, the reactances will cancel, and the series combination of crystal and the two tanks become a high impedance open

circuit. Neat trick.Those varactor diodes act as elec-

tronically variable capacitances that raise or lower the tank frequencies. Onthe positive modulation swings, both tanks will increase their resonant frequencies and vice versa.

Your final result is a reactance frequency modulator whose resonance frequency is set by the crystal butrapidly shiftable either way by the multiplexed audio. Usually, a frequency change varies as the square root of a capacitance change. But, because a pair of varactor diode capacitors is changing, your resonant frequency changes linearly with the modulation input.

At any rate, Q3 is a Pierce style oscillator which can oscillate at the frequency determined by the highest impedance sum of the crystal’s third overtone resonance and the reactance modulator tanks. 88.1 Megahertz is used in my particular sample, with a final trim given by TC2.

The fundamental crystal frequency is way down at 29.7 Megahertz, but the oscillator tries its best to run at 88.1. The resultant waveform thus has some uneven subharmonic lumps.

It is very important to keep the loading on most any modulated FM oscillator constant. Especially when using an overtone crystal. So, a buffer and driver transistor follows at Q4. This in turn drives a special bandpass filter (probably a surface acoustical wave, or a SAW device) to eliminate any subharmonics and out-of-band harmonics. Only the crystal’s third overtone at 88.1 Megahertz is allowed through the filter.

Even with the attenuation through the bandpass filter, the output signal isstill too strong to directly couple into any FM receiver’s antenna, so it gets further attenuated by R20 and R21.

Recall that supply power is only turned on when you want to listen to your CD player. When the 1.4 vdc supply voltage is present, relay driver Q4 and spike supressor D4 pull in the relay, connecting the rf converted CD audio directly on into your auto radio antenna input. At the same time the antenna is disconnected to prevent any back radiation or unintentional broadcasting. You do, of course, also have to pushbutton select 88.1 Mhz on your car radio for CD audio.

52.5

May, 1992

Fig. 5 – AN ANTENNA CAN BE ADDED as shown to the CD-FM-1 for your initial short range FM broadcasting experiments. Be sure to insulate the far end of your coupling gimmick. Experiment to get the best length and orientation.

1234BPF1

Thirty inchvertical wire

shielded case

newgrommet

Once again, this description is for the CD-FM-1. The XA-7A does use a somewhat different circuit that we may look at in a future column.

Hacking the CD-FM-1

In the absence of a CD player, the CD-FM-1 can get activated by connecting the AUX input to the +12 volt supply. Your left and right audio inputs are normally at "line" level; additional gain will be needed for most microphones. Any and all audio connections must be shielded.

The antenna changeover relay may be optionally defeated by shorting R23. Supply current is 30 mils with therelay active and 17 mils with it defeated. Another four mils could be saved by disconnecting your AUX input and shorting collector to emitter on Q6. And nearly another mil by removing R22. The remaining power needed by your "useful" part of the circuit is then 1.4 volts at eleven mils, or around fifteen milliwatts.

With these power reductions, you could probably substitute an ordinary 9 volt "transistor" battery for your 12 volt supply. But do be sure to turn the power off when not in use.

Theoretically, you might want to replace the dynamic regulator Q8 and substitute a single AA cell instead. A bypass cap or two would also be a

good idea if you try this. One way or another, though, you can easily get this circuit down into the millipower range. But not micropower.

A possible antenna takeoff point forany low level direct broadcasting experiments seems to be the collector of Q4. Figure five shows how to route a thirty inch antenna wire through a grommet in the case. I got a 50 foot useful range with a good car radio this way. Be sure to insulate the wire tip toprevent possible shorting of the dc supply or damaging the filter. A far cleaner but weaker takeoff point can be the pin 4 filter output.

While the BA1404 supply voltage can be raised as high as three volts, doing so may change the performance of the reactance modulator.

The best way to increase the range is to improve that antenna on your receiver. Be sure to connect a good receiving antenna and disconnect any cable connections. Experiment with the antenna orientation; vertical may be best for car radios and horizontal may be better for home hi-fi.

The range can also be improved by placing a ground plane, such as a grounded cookie sheet (or preferably something bigger), under your transmitter. This could give you a hemi pattern with double field strength.

A directional receiving antenna,

such as a correctly cut Yagi can also dramatically improve your range.

Note that lower power plus good antenna matching and orientation will give you vastly more range than will high power and poor or improperly aligned antennas.

While there is that extra booster amplifier remaining unused in the BA1404, it might be tricky to access and still remain stable. An external boost circuit could also get built up using a 2N918 transistor or something similar. This would best be done in a separately shielded and a properly de- coupled box. Do not, under any circumstances, attempt to amplify the unfiltered output. For doing so will create unacceptably strong outband signals. Especially at 29.7 Mhz.

What can you get away with in the way of increased power? Any boost at all gets you into a legal gray area. But,as a practical matter, if your dc input power to your boost stage is under fifty milliwatts, and if nobody ever complains, and if your total useful range is well under a hundred feet, andif you use these yourself rather than selling them to someone else, you can probably get away without any seriousproblems or hassles.

On the other hand, using one of these as a prediver to broadcast heavy metal to your entire college campus is a very big no-no.

Another Contest or Two

This CD-FM-1 is one of the most hackable projects to come down the pike in a long, long time. For here we have all of the compact and millipower core circuitry needed for one very high quality and quite stable FM stereo (or mono) broadcaster all in oneplace and ready to go. With the nasty stuff fully debugged. And one which works just fine with synthesized hi-fi and auto receivers.

For our first contest this month, just tell me about a new or unusual usefor a short range and high quality FM stereo or a mono wireless transmitter. Or show me a variation on the circuits we just looked at.

There will be all of those usual Incredible Secret Money Machine II book prizes going to the dozen or so best entries. Plus an all-expense paid (FOB Thatcher, AZ) tinaja quest for two going to the very best of all.

52.6

Hardware Hacker

DYS & OTHER RESOURCES

Brookstone127 Vose Farm RoadPeterborough, NH 03460(603) 924-9541

Harriet CarterStumps RoadNorth Wayles, PA 19455 (215) 361-5151

Comb Corp720 Anderson AvenueSt Cloud, MN 56395(800) 522-3035

Crutchfield1 Crutchfield ParkCharlottesville, VA 22906(800) 336-5566

DAK8200 Remmet AvenueCanoga Park, CA 91304(800) DAK-0800

DamarkBox 29900Minneapolis, MN 55429(800) 729-9000

47th Street Photo36 East 19th StreetNew York, NY 10003(800) 221-7774

Harbor Freight3491 Mission Oaks BlvdCamarillo, CA 93011(800) 423-2567

Hello Direct140 Great Oaks BlvdSan Jose, CA 95119(800) HI-HELLO

J&R Music World59-50 Queens-Mid ExwayMaspeth, NY 11378(800) 221-8180

Micro-Mark340 Snyder AvenueBerkeley Heights, NJ 07922(800) 225-1066

Northern HydraulicsPO Box 1499Burnsville, MN 55337(800) 533-5545

Porter CameraBox 628Cedar Falls, IA 50613(800) 553-2001

QuillPO Box 50-050Ontario, CA 91761(714) 988-3200

Real Goods966 Mazzoni StreetUkiah, CA 95482(800) 762-7325

Tandy Leather1400 Everman ParkwayFt Worth, TX 76140(817) 551-9770

Taylor Gifts355 East Conestoga RoadWayne, PA 19087(215) 789-7007

JC Whitney1917-19 Archer AvenueChicago, IL 60680(312) 431-6102

DYS Resources

I thought we’d do something a tad unusual for our resource sidebar this month. There’s a group of direct mail outfits that I will call DYS, short for Distressed Yuppy Surplus. All these folks specialize mostly in overpriced toys for the non-technical types. But every once in a while, an electronic gem or two shows up at a really unbeatable price. Or a useful tool. Or a great idea. So it pays to get and stay on their mailing lists.

An example or two: Those "meals in minutes" food vacuum packaging machines seemed to bomb out as a Yuppy prize. Their intended use was to package single portion leftovers so they can be frozen, boiled, or nuked. And they are great for just that. But at $29 each via DYS, these make very effective software and book vacuum packing machines. Be sure to get the type that has the little electric pump with it. Plain old Baggies work just fine with these.

Those automated bread machines also bombed at retail. Mostly because far too many females viewed them as an outright threat and throw both the machine and whoever gave it to them out of their house. So I got one via DYS. Around here these days, any bread that is even twenty minutes old is considered "stale", and even the birds won’t touch it.

You do have to be selective. For instance, a CPM computer is pretty much worthless at any price. As is any laser printer that does not speak real PostScript. As is any teletext receiver with no teletext to receive.

My three favorite DYS sources are Dak, Comb, and Damark. But every once in a while, a good solution to a technical problem can even be found in such unlikely sources as Taylor Gifts or Harriet Carter.

I thought I had a lot more of these DYS catalogs than I could find at column deadline time. Is JS&A still around? They invented DYS in the first place. How about the Sharper Image folks? So why don’t you tell meabout the rest of them?

As a second contest, just tell me about any non-obvious direct mail resource that can be used to get ideas and solve hacking and other technical problems. Include a sample copy if

you are able to do so.I’ve also added a great heaping

bunch of other unusual direct mail sources to our sidebar. While several of these are clearly not DYS, they do offer very interesting and very useful catalogs. And every hacker should definitely know about them.

New Tech Lit

From Analog Devices, the fat new Data Book Volume 10 on their analog integrated circuits. From WSI, a new Programmable Peripherals Design and Applications Handbook which includes lots of free demo software. From Intel, their new PLD Shell Plus programmable logic design and its supervision software.

Assorted free samples of Kydex thermoplastic sheets are obtainable from Kleerdex. This stuff looks great for custom thermoformed cases and enclosures. With lots of colors, thick- nesses, and surface finishes. And free tactile dome keyswitch samples are available through Snaptron. Finally, Avery Dennison now has test fixture samples of their FasTape UHA super strong clear adhesives.

A reminder that I still have lots of Book-on-demand bound reprint sets available on pretty near all of my recent columns. Included are Ask the Guru I, II, and III, Hardware Hacker IIand III, LaserWriter Secrets, and Blatant Opportunist. Write or call me for more details.

Don Lancaster’s

Hardware HackerJune, 1992

Dye-based solar energyAnother sad patent storyNeo-Geo interface cablesMicro-avionics newsletterRGB monitor fundamentals

53.1

Fig. 1 – ANOTHER SOLAR BREAKTHROUGH? The dye-based solar method uses a large area monolayer of individual dye molecules to act as optical antennas and rectifiers. An electron "borrowed" from the electrolyte by the dye gets its energy level raised by an incoming photon, jumps the rectifying semiconductor gap, delivers useful load power, and then returns to the electrolyte. The high efficiency process is related to the first stage of plant photosynthesis. All the materials used are cheap and fairly low tech.

Transparent glass cover

Transparent conductorLithium hydroxide or

other electrolyte solution Powerload

( - )

(+)

Dye molecule monolayer

A thin but very roughsemiconducting layer

of titanium dioxide

Bottom conductor

Incoming solarenergy

Uh whoops. On back in that pc layout for the sync stripper and universal video interface (RE April 92 page 65, Fig 2),

it seems one of my last minute layout "improvements" left one extra trace from pin 9 to that SYNC output line. Sorry about that. If you have already etched your board, just cut this tiny run out.

Figure one is correct, and the layoutshown in these reprints has also been fixed.

Moral: It is always the things that you thought you triple checked that are certain to return to haunt you.

We will see several other possible changes to the sync stripper in just a moment when we look at some new Neo-Geo interface ideas below.

An update to the crystal stabilized FM stereo broadcaster circuit that we looked at last month: I’ve now had a brief chance to check into that new Sony XA7A unit. While it uses pretty much the same circuit we did look at, it seems more costly, klutzier, and far harder to hack.

The BA1404 uses a surface mount. There’s some tight and tiny shields, and some awkward "3-D" component arrangements. Sony appears to be getting two channels by pulling their crystal an astounding 200 kilohertz in either direction. I’d bet their stability isn’t as good as a Pioneer CD-FM-1.

Speaking of which, it should be possible to significantly improve the CD-FM-1 range by replacing the SAW filter load used by Q4 with a simple tapped resonant tank located outside of your existing shield. This would switch Q4 from class A over to class C operation. Some bypassing on R19 could also help, as might lowering its value somewhat.

More details when I get a chance. Meanwhile, do let me know what you come up with on your own.

Patents Again

The morning mail had yet another sad example of a hardware hacker done in by the patent system. Or more correctly, done in by the outlandish

popular myths and all the gross misconceptions surrounding patenting. One more time: Any hardware hacker based small-scale involvement in the patent system is absolutely certain to result in the net loss of time, energy, money, and sanity. Your state lottery is a vastly better investment.

This example involved an Oregon inventor who sent me a copy of his new patent and asked for my help in marketing it. The patent is intended to recover electrical energy from a steam line by impinging the steam onto a piezoelectric generator. The patentee admitted he lived in a very "remote area" where all research was difficult.

And he did specifically ask me for comments, so here goes…

Well, it must have been my kind of remote area. There was obviously no telephone available to call the Dialog Information Service, and no postal or UPS service to receive UMI reprints. Their local library had to be so small that they had no Uhlricht’s Period- ical’s Dictionary which included the EPRI Electric Power Research Insti- tute Journal.

And, of course, no Encyclopedia of Associations which would include the

Association of Energy Engineers with their great conference publications on this type of cogeneration device.

I felt the patent was rather weak. I think I could personally find all kinds of prior art way back in the 1890-1930 time frame. And I do think the idea would be so totally obvious to any "practitioner in the field" that prior art would not even be required to quickly bust this patent. In fact, attempting to defend it could easily lead to a nasty old frivolous litigation countersuit.

"Outside of that Missus Lincoln, how was the play?" Well, I just don’t know of any higher power electricity- producing piezo generators. Piezo tends to be grossly inefficient and involves frequencies and impedance levels that are hard to elegantly deal with at higher power. These tend to have lousy power factors, since piezo transducers are often very capacitive. Their optimum working temperatures are well below that of live steam.

Further, we obviously have a heat engine here that has to obey the laws of thermodynamics. The best possible efficiency (also known as the Carnot efficiency) would end up rather low. Which is why we don’t have too many

53.2

Hardware Hacker

Fig. 2 – THIS SYNC AMPLIFIER can take "linear" or "weak" RGB composite sync signals and make them CMOS and /or TTL compatible. It also gives you anoptional and rarely needed active high sync output.

1 2 3 4 5 6 7 8

16 15 14 13 12 11 10 9

4049

S—

Y—

N—

C—

out(normal)

SYNC out(rare)

+5V

470K

10K0.1 µF

0.1 µF

Weak or linearcomposite sync

input

steam engines these days. And I feel the P-V (pressure-volume) diagram forthe new proposed impingement systemwould be absurdly far away from the best possible. It is clearly not at all adiabatic.

I would be quite surprised if the overall electrical recovery efficiency could ever exceed 0.1 percent. Thus, I feel this product would never be able to pay for itself or for the time value ofthe money used. Let alone recover anyuseful power.

So, I’d guess my answer on any marketing of this product would be "Uh, to whom?"

Now, there are all sorts of exciting steam recovery developments going on. These do involve bottoming and scavenging cycles and may use exotic fluids other than water vapor. And they are revolutionizing commercial electric power production by sharply improved efficiencies. And the pulse combustion furnace folks are playing lots of neat games in super efficient latent heat (gas to liquid) recovery. Sothere are bunches of new possible opportunities in this area. Some of them eminently hackable.

By the way, one ancient but quite readable book on thermodynamics is Sanford’s Heat Engines, found in the Doubleday Science Series. No hacker can afford to ignore the fundamental laws of thermodynamics.

Where to go from here? First and foremost avoid any and all involve- ments with the patent system in any way, shape, or form.

Do so religiously.

Second, get yourself a fresh copy ofThe Case Against Patents, either in my Blatant Opportunist reprints or as our GEnie tutorial PSRT textfile #162 NOPATENT.TXT. Rumor has it that this reprint may also shortly appear in the Whole Earth Review.

Third, there is a unique magazine known as Midnight Engineering that specifically supports the small scale developers, product prototypers, and startups. Giving proven and realistic help. Free samples on request.

Inventing, of course, is a highly reprehensible and incurably addictive social disease. One that is simply not talked about in polite company. So, fourth and finally, you may want to join some AA type support group. A typical example group would be the Zimmer Foundation, associated with the Michigan Inventor’s Council. Just be certain your selected group isn’t a marketing scam in disguise.

Another Solar Breakthrough?

Lots of credibility has been newly given to dye methods of solar energy conversion. As we have seen in past issues, certain dye molecules can act as both an antenna and rectifier, converting any incoming photons into an electron current. The dye method is potentially very cheap, very efficient, and should end up quite easy to mass produce. Only low cost and low tech materials are involved.

Do check out the October 24, 1991 issue of Nature. (vol 353 #6346). Es- pecially Thomas Mallouk’s Bettering nature’s solar cells (on pages 698-99)

and also Brian O’Regan and Michael Gratzel’s A low-cost high-efficiency solar cell based upon dye-sensitized collodial titanium dioxide films (on pages 737-739).

Some librarians appear to have lots of trouble finding Nature, possibly because it is British. Which is a real mystery, since Nature is regarded by most of those in the know as the finest and most significant science journal anywhere in the world.

Obviously, any magazine that gets on up to weekly issue #6346 must be doing something right. If you get any static picking up any Nature copies locally, scream and holler and stamp your feet. Or use the address found in our Names & Numbers sidebar.

Figure one shows you the general idea behind any dye-based solar cell. The cell uses liquids and is related to awet cell battery. An electrolyte of a lithium salt or something similar gets used. The uppermost terminal is a conductive metal film under a clear glass. The bottom terminal is also a conductive metal film. Onto this film, a very thin and very rough layer of a titanium dioxide semiconductor gets deposited. Together these can form a metal barrier diode.

The semiconductor film is made as rough as possible to greatly increase its surface area. The current effective areas are in the 2000:1 range. A one molecule thin monolayer of trimetric ruthenium dye then gets deposited on the semiconductor surface.

The single dye molecules can act as both an antenna and a rectifier. An existing electron in your electrolyte solution will have its energy level increased by the incoming optical photons. These high energy electrons jump the semiconductor junction, go on through the load delivering useful power, and return via your top electrode, creating a self-rectifying and light induced photocurrent.

So far, the actual efficiencies are only slightly better than poly silicon cells. But all of the materials are far cheaper (titanium dioxide is used to make white house paint; only small amounts of dye are used). They also lend themselves to larger area, high volume processing.

The theoretical efficiencies of dye based systems are quite high. There are plenty of potential directions for

53.3

June, 1992

Fig. 3 – THE NEO-GEO AV-OUT rear connector has both NTSC and RGB output pins available. Here are the key details.

24

1

67

3

5

8

3 NTSC VIDEO

Plain old NTSC composite videoappears on this line. The synctips are at ground.


4 +5 VOLTS DC

A limited amount of +5 voltssupply power may be drawn outof this pin for sync amplifiers.

Limit current to 50 milliamperesand use thorough bypassing.

5 GREEN VIDEO

For linear RGB monitor use.One volt peak-to-peak getsinternally capacitor coupled.

2 GROUND

Used for all cable shields, video return, and any syncamplifier grounding.

7 /RGB SYNC

For linear RGB monitor use.Active low combined verticaland horizontal sync pulses.

1 volt capacitor coupled sourceis not CMOS/TTL compatableand may need amplification.

8 BLUE VIDEO


6 RED VIDEO


1 MONO SOUND

The monophonic sound outputappears on this pin.

One volt peak is suitable foramplifiers but not headphones.Use separate shielded cable.

Neo-Geo AV/outrear panel female

Use standard DIN-8male connector

ongoing improvements. And the long term durability looks good.

There are several remarkable sim- ilarities between dye-based solar and plant photosynthesis. In fact, the biggest difference is that dye-based solar stops with generated electrons, while photosynthesis will go on and use the high energy electrons to drive the intermediate chemical reactions which can ultimately create sugars, cellulose, and other tasty stuff.

Dye based solar is already more efficient than the best that today’s plants can do; On the other hand, the plants can create and fix themselves atvery low costs.

More on this as the drama unfolds. But, from here, it does seem like dye based solar has the potential to end up as a real winner.

RGB Video Fundamentals

I have recently been working with Dennis Carper of Redmond Cable in interfacing all sorts of video games to all types of leftover surplus computer monitors. So, I guess it might be a good time to review some of the fundamentals of RGB monitors.

The reasons we go to the separate red-green-blue route in the first place are for picture quality and for picture resolution. Regardless of how much trouble you go to, it is simply not possible to glomp onto the antenna terminals of an ordinary tv set and display anything even remotely near what is needed as a bare minimum for all of today’s color computer displays or premium arcade video games. The needed bandwidths and scan rates are simply not there.

Unlike broadcast signals (such as NTSC or PAL or SECAM), there are no universal standards being used for RGB monitors. If it has three separate video lines on it, it is an RGB system. Period. Thus, you will have to be very careful what your video source and your video monitor are capable of before you try to connect them.

The simplest of RGB systems use "TTL" monitors. These do not accept video as such. Instead, they receive digital logic signals which turn their red, green, and blue beams entirely offor on. Thus you can only get eight possible colors. All eight of which are always fully saturated. Some TTL monitors include a fourth brightness

line that gives you a choice of "full" or"half" bright, upping the apparent color total to sixteen.

Instead, on a linear RGB monitor, all shades of all colors are possible. Linear monitors need much more in the areas of video amplification and linearization (or gamma correction) circuits. Obviously, linear monitors are required for "real" video from a cable or broadcast source, or anytime else you need a very wide range of hueand saturation values.

Most linear monitors are not too fussy over accepting interlaced scans, as get used on standard tv; or the non- interlaced scans, as must get used on most data displays.

But linear monitors are extremely fussy over their horizontal scan rates. Ordinary tv uses the horizontal scan rate of 15.735 kilohertz for color or 15.750 kilohertz for black and white. Most computer scan rates are double this, up in the 32 kilohertz range. And

premium systems can have scan rates of 80 kilohertz or higher.

Unless your monitor is carefully designed to be a multisyncing type, it will only accept a very limited horizontal scan rate range. Thus, there is no way you could use an ordinary broadcast RGB monitor to display a Mac or VGA output. It flat out can not operate at the higher scan rates.

One of the ruder surprises to Apple IIgs people downgrading to a Mac LC is that their old color monitor will no longer work. Their IIgs monitor is a broadcast-only style, while those LC video scan rates are on up in the 30 kilohertz range. Fortunately, a simple jumpering option (which we saw a fewcolumns back) lets the LC use an ordinary and cheaper VGA monitor.

Thus, you have to be sure that your intended RGB monitor is capable of accepting the horizontal scan rates provided by your video source. Some combinations simply will not work.

53.4

Hardware Hacker

Fig. 4 – TYPICAL NEO-GEO RGB INTERFACE connections. The details and pinouts vary with your choice of monitor. The sync amplifier shown may or may not be needed. Custom cables and kits are available from Redmond Cable.

sync amplifierfrom figure two

+5VDC

/SYNC

GND

GREEN

BLUE

RED

SOUND

/SYNC

GND

GREEN

BLUE

RED

AUDIOINPUT

4

7

2

5

8

6

1

?

?

?

?

?

NE

O-G

EO

(A

V-o

ut D

IN-8

mal

e)

RG

B M

ON

ITO

R(p

inou

ts v

ary

)

A final major consideration is the monitor’s resolution. The resolution isset by the video bandwidth and the pitch of the color bars or dots on the screen. Images will smear if you try to view them on any monitor whose resolution is too low for the intended application. The results can end up anywhere from a slight eyestrain to totally unviewable.

So, a second rule: Make absolutely certain you test and use any monitor inits intended final use before you actually pay for it.

Your video lines could be high impedance cables if the runs are short, orterminated ones (usually 75 ohms) for longer distances. A fair amount of power is required to properly drive a terminated video cable. Maxim is one good source for video drivers. Video cables are best done either as fully shielded, or, at the least, as twisted pairs. If any separate grounds are provided, they should be used as they were intended.

If your video source has any dc offset present (such as the emitter follower outputs of a Super Nintendo, then you must provide for a capacitor coupling between your source and the monitor. Very large capacitors are recommended, of at least 220 microfarads or more. But these may already be built in, so check first.

There are several synchronizing options used in RGB systems. Some systems tack sync signals onto the green channel and later strip them off. But most systems have separate sync line(s) which deliver the horizontal,

vertical, or composite sync signals.To further confuse matters, sync

lines can be smaller one volt signals atanalog levels, or can be TTL or CMOS compatible. Others may be at TTL levels, but end up too small for CMOS and too weak for TTL. We saw a SuperNintendo workaround for this last month using a simple 680 ohm resistorto ground.

Typical sync lines are active low meaning that your sync tips are at ground. But a few (especially earlier Commodore products) demand an active high composite sync.

Figure two shows you how to use several inverters to amplify low level sync signals into full CMOS and TTL compatibility having your choice of either active low or active high sync tips. Your first stage can be a biased inverter amplifier having a gain of twenty or more. The second inverter further cleans up your now-digital waveform, while the third and fourth stages act as inverters or drivers.

If you try this linear amplifier stunt with other CMOS gates or inverters, besure to use "single stage" unbuf- fered (UB) versions; other buffered ones may have too much gain and could oscillate. More details in my CMOS Cookbook.

Our sync separator and universal video interface from two months back is easily modified to provide suitable sync amplification for the Neo-Geo or Super Nintendo.

Sound is separately dealt with on a RGB system. Sometimes, there will be no sound at all. One clue here is the

absence of any volume control. Radio Shack makes a neat little $11 lab amplifier that can sit in for you. Other options are monophonic sound, stereo sound, or a multiplexed stereo sound accepting R + L and R - L inputs. SuperNintendo uses multiplexed sound.

If you forget to demultiplex, one channel will sound monophonic, and the other might sound awfully tinny and just plain "wrong". To properly demultiplex, you add the two signals together to get the right channel and subtract them to get the left one.

Regardless of your sound system, totally shielded audio cables are a must. Ideally, they should be totally separate from all your video cables, owing to the strong "hum" and "buzz" induced by vertical rate signals.

So, what can you interface to who? Use your oscilloscope to view all the normal outputs of your video source run in their intended way. Then do the same for the "normal" inputs to the monitor.

Some hints: To tell if a source is capacitor coupled, briefly connect a 470 ohm resistor between the pin and ground or +5. If the scope display bounces around and slowly drifts on back, you are ac capacitor coupled. If it remains in the initial position (or possibly gets slightly smaller), then you are dc coupled. Be sure to note any fixed offset voltage.

To find out your source impedance, note that any resistive load equal to your source impedance will drop your output signal level to one half of the open circuit value.

Neo-Geo Interface Ideas Sorry, but our renowned panel of

experts (the munchkin division of Special Editions) were not at all impressed with the new Neo Geo game system. Their preference for Super Nintendo was totally overwhelming, and I will certainly defer to their expertise. But, if you happen to like the Neo Geo system, figure three can show you the rear A / V out interface connector pinouts.

There are several interesting interface options here. Present are the usual NTSC composite video line on pin 3, a ground on pin 2, and a +5 volt supply on pin 4. You could use this supply for such low current needs as modulators or sync amplifiers. For

53.5

June, 1992

ELECTRONIC SURPLUS RESOURCES

All Electronics Corp.PO Box 567Van Nuys, CA 91408(800) 826-5432

American Science & Surplus601 Linden PlaceEvanston, IL 60202(708) 475-8440

C & H SalesPO Box 5356Pasadena, CA 91117(800) 325-9465

Circuit SpecialistsPO Box 3047Scottsdale, AZ 85271(800) 528-1417

Edmund Scientific101 E. Gloucester PikeBarrington, NJ 08007(609) 573-6250

Fair Radio SalesPO Box 1105Lima, OH 45802(419) 227-6573

Herbach and Rademan18 Canal StreetBristol, PA 19007(215) 788-5583

Marlin P. Jones & Assoc.PO Box 12685Lake Park, FL 33403(407) 848-8236

Archie McPheePO Box 30852Seattle, WA 98103(206) 547-2467

R & D Electronics1224 Prospect AvenueCleveland, OH 44115(216) 621-1121

Surplus CenterPO Box 82209Lincoln, NE 68501(800) 488-3407

Surplus TradersPO Box 276Alburg, VT 05440(514) 739-9328

RGB use, there is a red line on pin 6, a green line on pin 5, and the blue line on pin 8. These are capacitor coupled video from a 70 ohm source.

Their RGB active low sync line appears on pin 7. It is also in the form of capacitor coupled video at a one volt amplitude. Thus, the sync line is not presently TTL/CMOS logic compatible, and you may need to use the syncamplifier of figure two.

Figure four shows you a baseline RGB interface for the Neo-Geo. The connector is a standard DIN-8 that is Radio Shack stock. As with our previous Super Nintendo interface, stock and custom cables, connectors, and any and all individual parts are obtainable through Redmond Cable.

Surplus Resources

As our resource sidebar for this month, I decided I would gather together what I feel are only the best of the very best in hacker surplus stores. These are the ones I have used consistently over the years and can personally recommend.

The best surplus store anywhere, of course, is Jerryco, who’ve recently become American Science & Surplus. They are strong in electromechanical parts and unusual materials.

The highest profile surplus outfit is Edmund Scientific who are really useful for magnets and optics.

For genuine World War II vintage surplus, Fair Radio Sales is the pre- eminent place to go. For heavier iron stuff, especially motors, steppers or hydraulics, try either C&H Sales or Burden’s Surplus Center. And for the best prices on a wide variety of components, try Surplus Traders.

Several other outfits I have found useful include Herbach and Rademan (infrared people detectors), Marlin Jones (power supplies and steppers), Circuit Specialists (for harder-to-find hacker integrated circuits), Time Line (solid state imaging chips), and either All Electronics or R&D Electronics (generally good electronic buys).

Finally, for totally outlandish plain old weird stuff, Archie McPhee is it claws down. Where else can you get a three foot rubber iguana?

These are just my own personal selections, and I am sure you have your own favorites as well. But why don’t you tell me instead?

For our contest this month, just tell me about your favorite surplus or any other hacker-friendly and reasonably priced source of supply for unusual goodies. There will be several of my Incredible Secret Money Machine II book prizes, plus an all-expense-paid (FOB Thatcher, AZ) tinaja quest for two going to the best of all.

If possible, include a catalog or put me on their mailing list. Be sure to send your written entries directly to me here at Synergetics rather than on over to Radio-Electronics editorial.

New Tech Lit

The Ashtech folks now offer some really great and reasonably priced ($100) four-day courses on those GPS navigation systems, besides offering bunches of free ap notes.

From OKI Semiconductor, some speech application notes on the solid state speech synthesis chips.

The Micro-Avionics Newsletter is a brand new and sorely needed labor- of-love hacker pub that focuses on the remote controls, navigation, auto- piloting and the television links used on low end and amateur radio controlled R/C models and other aerial

platforms. Sample issues are $5.Another very interesting magazine

is Lighting Dimensions, a slick and well-done publication intended for the stage, theater, television, and rock concert lighting specialists.

It’s been a while since I mentioned the Society for Optical Engineering. Their freebie SPIE Technical Publi- cations lists all sorts of unique books and reprints on such goodies as solid state gyros, high speed photography, robot vision, lasers, liquid crystals, and even on binary optics, a stunning and revolutionary new field that I hopeto eventually cover.

There are several exciting new developments in hacker printed circuits these days. The Kepro folks now offer a new How to make printed circuit boards booklet. A product called PCBTF-1000 is a brand new transfer film for that direct toner method, newly available by way of Techniks Incorporated.

And I’ve just posted my shareware printed circuit circuit layout package over to GEnie PSRT as our file #401 PRNCRCT.GPS. Plus our summary tutorial on new hacker printed circuit techniques as file #419 NUTS3.PS.

53.6

Hardware Hacker

Don Lancaster’s

August, 1992

Hardware HackerSanta Claus machine BBSDirect toner breakthroughLaser printer repair videoSynchronous rectifier ideasFundamentals of correllation

54.1

Fig. 1 – A "LOCK-IN AMPLIFIER", or synchronous demodulator is an older andsimpler example of electronic correlation. In this driveway detector, the desired"no cars" signal can easily be extracted from sunlight or other interference.

1 kHzsquare wave

generator

1 kHznarrow band

amplifier

synchronousdemodulator

1 kHz chopped light beamrouted accross drivewayfrom LED to photodiode

Alarmoutput

1 kHz demod reference

Aquickie update before webegin: We’ve found out thatmost of those popularwireless broadcaster circuits

will no longer work because nearly allof the newer synthesized receiverspositively exactly on-channelfrequencies. In recent columns, we’veseen how that caneasily be modified into a fine crystalcontrolled stereo broadcaster.

At the time, I didn’t really believethat a plain old third overtone crystalcould really get pulled that far and stillprovide a quality result. So, Iasked an outstanding designerby the name of Jim FitzSimons to do acircuit analysis for me. The bottomline: Yes, you can pull an ordinarythird overtone crystal far enough andlinearly enough to do the job.

Some other fallout from theanalysis: The temp comped voltsupply is quite critical for linearity,and you should try and raise thisvoltage. And the varactor modulatordoes its work by shifting theresonant point of the crystal.

This is one topic that can get realhairy fast, but let us try it anyhow.Many fancier electronic applicationsneed techniques of onesort or another. A few of the zillions ofpossible examples include spreadspectrum communications, machinevision, radar, navigation, speechrecognition, video compression, radioastronomy, planetary probes, fuzzylogic, pattern recognition, etc…

Well, correlation is simply. A match against some

original signal. Or any replica of thatsignal. Or against some expectedpattern. And the longer you look foryour match, the deeper the noise youcan extract it from. With luck and adecent correlator, all your noise andinterfering signals will cancel out or,at the least, pile up far more slowly.As a general rule, if any electronicsystem has to push the limits of whatcan be done, correlation often will endup playing a big role.

A trivially simple ferinstance ofcorrelation is the Morse Code. You orsome machine receive a pattern ofshort-long-short-short. You can thencompare that pattern against a storedlist of all of the acceptable charactersand numbers. A beginner might note"That sounds like "li-no-le-um" andlinoleum starts with an "L". Withpractice, you can do a near immediatecorrelation, rather than having to goand compare each and every possiblepattern. You simply "hear" the code asletters, in the same way a musician"sees" notes. But, inside your brain, awetware correlation is happening.

Let’s see how correlation can helppush the detection limits of a simpleproblem. Say you have a very longdriveway and want to know wheneveranyone shows up. You put a bright

on one post and a photocell onthe other and build an "electric eye".And it works just fine at night.

But when the sun comes up, thephotocell saturates and nothing seemsto work. You next try some obviousnon-correlation cures to see if theyhelp. You raise the power, add adeep red filter and some focusingoptics to improve your signal andreduce the noise. You amplify onlythose received signal changes that arein the expected frequency range of apassing car. And you even use somesort of loop to keep the sensedlight in the linear detector range.

Any of these stunts should work in aplain old driveway sensor, but let’spretend that, after trying everythingyou could think of to improve yourlinearity, noise rejection, and signal tonoise ratio, that things still aren’t quitereliable enough. Now what?

Figure one shows you one of theoldest and simplest of the electroniccorrelation techniques. It is called a

, and maystill even go by its ancient name of a

. You chop yourat an audio rate, turning it on and offat, maybe, times a second. Youdesign a receiver that only amplifiessignals near Hertz.

Now for the tricky part. Instead ofjust detecting your Hertz, you

androute that to a demodulator that obeys"amplify when I’m positive,; amplify

when I’m negative".Well, neglecting any phase shifts or

delays (these can be easily gottenaround), your real received signal will

match your signal copy, and itshould nicely pile up. But anyinterfering signals will sometimes addand sometimes subtract. So, mostinterference cancels.

By correlating, or

, you have quite dramaticallyimproved your ability to reject nearlyall types of potential interference.

You can also view a synchronous

FM

CD-FM-1

FM

CDVCXO

VCXO1.4

GPS

LED

LED

AGC

LED

1000

1000

1000

AND INVERT

demand

Pioneer

not

series

correlation

lookingfor a match

synchronous demodulator

lock-in amplifier

take a copy of your original signal

always

looking for anexact match for an expected inputsignal

Electronic Correlation

54.2

Hardware Hacker

Fig. 2 – HERE ARE FOUR POPULAR METHODS to do electronic correllations.

(A) An analog correllator using a"plus or minus one" amplifier.

10K

10K

4.7K 4.7K

-

+

signal in

mask in

analog switch1/4 4066, etc.

matchoutop-amp

(B) Serial digital correlator usesan exclusive-NOR gate.

signalbit in

maskbit in

1 = same0 = different

matchbit out

(C) Parallel digital correlator usesgates and a special adder.

"How

man

y on

es a

repr

esen

t in

the

wor

d?"

spec

ial a

dder

mat

ch

out

s0m0

s1m1

mnsn

(D) 2764 EPROM made into aparallel 8-bit correlator.

mas

k i n

s ig n

a l i

n

ma t

c h o

u t

2764EEPROM

demodulator as an extremely narrowbandpass filter that automatically andexactly tracks your input signal. Evenif your input signal is varying. Butsynchronous demodulation goes onestep further than a simple filter. Notethat signals of the wrong phase getmore or less rejected. For instance,any interfering signal that happens tobe at a phase angle of plus or minusdegrees get rejected.

Go through the math, and you’llfind that a sync demod offers a "free"additional of signal tonoise ratio improvement over the bestdetector you can come up with thatdoes not use correlation. And threedecibels at or near a digital detectionthreshold can mean a big world ofdifference in reliability. From errorsper second to errors per hour.

In general, you do a correlation by and then by . You

first find how well a smaller piece ofyour received signal can match. You

might assign a for "agree" and afor "disagree". Then you add up (or

) each individual agreementor disagreement to get some overalltotal. The summed total is called your

. If your finalcorrelation coefficient ends up highenough, you vote "yes". Or else yousimply pass the correlation value on tomore circuitry that wants to knowrelative results.

Correlation can be done by usinganalog, digital, or mixed signals. Inthe digital world, you can correlate ineither a serial or parallel mode. Serialis slow and low in cost, while parallelis fast and complex. But serial may notbe nearly fast enough for manyreal-world uses. A special class ofmicroprocessors we know as

are arranged to domany correlation techniques faster andeasier than regular chips.

Several simple correlator circuitsare shown in figure two. For linearcircuits, a diode bridge or any fourquadrant multiplier should work just

fine. For high frequency work, the is a great choice.

But my favorite lower frequencylinear sync demod is the gated gainamplifier of . If the signal islow, the gain is . If it is highthen the gain is . This is asynchronous full wave rectifier thatdoes all of the multiplying for us. Afollowing stage will do theaddition for us. Often the addition canbe done with a network.

The fundamental digital correlationcircuit is the gate, otherwiseknown as an . This isshown in figure . A compare gategives you a one out if the inputs are

and a zero out if they are. For serial use, one compare

gate can be followed by an up-downcounter. For parallel use, bunches ofcompare gates are followed by aspecial pile of adders configured as a"how many ones are in this word?"circuit. Figure shows details.

Yes, you can go out and buy digitalcorrelator chips, but they do tend to bespecialized and expensive. and

are two bigsources. A second more popular routeis to use firmware and a digital signalprocessing chip.

On your own, you can easily andcheaply hack up an eight bit digitalcorrelator out of any plain jane

, following the details fromfigure . Your truth table simplyanswers the question "How many bitsmatch?" The answer will be a four bitword ranging from to .

For any sixteen bit parallel digitalcorrelator, simply precede a different

with quad gates.Correlation could also be done in

software. For instance, in PostScript,just do an sequence, followedby a "number of ones" table lookup.

An exact match against your initialsignal is called an .Attempting a match against anythingelse is a . Should youtry a match against some shifted ordelayed version of your initial signal,you’re doing a .

Ideally, your autocorrelations willalways strongly agree, and most ofyour crosscorrelations will more orless cancel to zero. But those shiftedautocorrelations get interesting in a

90

+1 -1

CPU

RFNE605

1A

RC

2-B

2C

2764EPROM

2D

-8 +8

2716 EPROM EXOR

completely

three decibels

multiplying adding

integrate

correlation coefficient

digitalsignal processors

Signetics

maskplus oneminus one

integration

compareexclusive NOR

identicaldifferent

TRWStanford Telecomm

eor not

autocorrelation

crosscorrelation

shifted autocorrelation

plus one

Building a Correlator

Correlation Functions

54.3

August, 1992

Fig. 3 – SHIFTED AUTOCORRELATION FUNCTIONS appear when youcorrelate a digital word against a time-shifted or bit-shifted replica of itself.These functions get important in a hurry whenever you are trying to lock onto anincoming digital data stream. These examples are from GEnie PSRT #427.

1000 100010 1000101 10010101

10000111

1000010101

10010101010

10000110011

100000011111

100000000011 100100101010 1000000101001

10000001011001 1000010001001011 1000001001110101 100000010111001

very big hurry.For instance, say you now have a

planetary probe flying past Neptune.The extension cord needed to deliveran exact copy of your autocorrelationsignal tends to end up a tad on thelongish side. Not to mention asteroidbreakage. The trick, instead, is to takea local shifted autocorrelation signaland move it around until you get astrong match to your incoming data.This is called . Untilyou have your local clone referenceprecisely locked to the incoming data,you can’t receive any useful info.

By far the most unusually uniqueautocorrelation function occurs withthe sequence . Like so…

1 0 0 0 1 0 0 0 ========= +1 +1 +1 +1 ----> 4

1 0 0 0 0 1 0 0 ========= -1 -1 +1 +1 ----> 0

1 0 0 0 0 0 1 0 ========= -1 +1 -1 +1 ----> 0

1 0 0 0 0 0 0 1 ========= -1 +1 +1 -1 ----> 0

Here we are adding. We arecomparing two bits at a time,and putting down a if they areidentical and a when they aredifferent. Only then do you add up thetotal results. Note that the second,third, and fourth examples representshifts of one, two, and three bits inyour target word. Amazingly, all ofthe shifted autocorrelation results areprecisely zero!

Very sadly, this is the knowndigital sequence that gives a "perfect"shifted autocorrelation. The longercodes will do all sorts of weird thingswith the shifted summations. Most ofwhich can end up as less than useless.Some of the more interesting (andmore useful) shorter autocorrelationcodes are shown you in figure three.

There are far fewer autocorrelationfunctions than there are possible bitcombinations in any word. Why?Because shifted bit patterns, mirror

patterns, and complementary patternswill all end up generating identicalautocorrelation functions.

The best possible autocorrelationcodes are called . Sadly,these are all short and are few and farbetween. Instead, when you are usinga long correlation code, you’ll oftenhave to settle for one that is simply"well behaved".

On any longer digital codes, mostcross correlation values will be verylow. For any code length, you couldeasily predict how badly a randominterfering noise code might crosscorrelate. Just use a messy piece ofmathematics known as the

. For instance, on a fairlyshort code of bits, only crosscorrelation will total to and oneother to . A mere twenty will sumto a value of .

Why twenty? Because there areonly twenty possible places in a bitword for the one bit errors. How manypossible errors of two bits? Gothrough the bionomial math and theanswer is a scant cases that sum to

. Of the possible bit

cross correlations, a huge willsum to or . Put anotherway, a tad over three quarters of allof those possible bit interferingsignals will be strongly attenuated byyour correlator. As you go to longercodes, the odds of noise interferencebecome astronomically low.

I’ve now posted a quick-and-dirtyautocorrelation generator to

as my file .As is, this will generate of thoseunique autocorrelation codes up toor so bits in length. Yes, duplicatecodes are discarded and not reported.And you can easily extend out thistechnique to quickly and accuratelyfind autocorrelation functions as longas bits!

Written in PostScript, of course.The trick is to put all your ones andzeros into a string. Then play aroundwith the string. This bypasses theprecision limits of any conventionaldigital arithmetic. Sneaky, huh?

We will be seeing much more oncorrelation in some future columns.Especially if we do get into more onspread spectrum communications and

"+1""-1"

20+20

-20+18

20-

190+16 1048576 20-

772616+4, +2, 0, -2, -4

20-

PSRT #435 AUTOCORR.PS

20

655361000

acquiring a lock

notvertical

only

Barker Codes

bionomialcoefficients

one

GEnie

all

54.4

Hardware Hacker

Fig. 4 – AS THESE TWO WILDLY DIFFERENT EXAMPLES show us, there arenow an incredible number of applications for electronic correlation techniques.

Linear time delay-vs- frequency

correlator

In a CHIRP radar system, a frequency swept pulse is transmitted thatpermits both high power (for long range) and narrow time resolution (forcloser target separation.) A linear delay-versus-frequency correlatorconverts the received target swept phase histories back into actualviewable or recordable target maps.

+vin

Switchmodedriver

+vout

In a SYNCHRONOUS RECTIFIER, power switches are turned on onlywhen conduction is desired. Because of the lower forward drop of aswitched transistor, the efficiencies can be much higher than usingordinary silicon diodes in low voltage, high current supplies.

navigation. I just wanted to give abare bones intro to a tricky topic here.All of those shifted autocorrelationfunctions are lots of fun to play with(and a winning school paper topic) justbecause they are there.

Let’s wrap this up by looking at twowildly different examples for elec-tronic correlation in figure five.

Say you want to build up a lowvoltage, high current power supply,maybe volts and amps. If you tryusing plain old silicon diodes for your

outputs, you’ll get a volt or two offorward drop across your diodes. Andlots of waste heat and a terribleefficiency. While the newerdiodes help some, even these are veryinefficient at higher currents.

But a properly chosen and drivenpower transistor could have a muchlower forward drop than a diode. So,instead of using diodes, you use fieldeffect transistors as switches set up as

. You turn yourtransistor on only when you desire

conduction and turn it off otherwise.The forward drop can be much lowerand the efficiencies much higher.

The synchronous rectifier is mostlikely your least elegant correlatorexample. Solar energy converters areanother area where high rectificationefficiencies are super important.

Shortly after World War II, pulseradar systems hit their limits. The

of a traditional pulse radaris inversely proportional to its pulse

; the is proportional to theenergy inside the . Ideally,you want an super powerful yet ultranarrow pulse waveform. And yew jestcaint get there from here.

The trick is to conjure up somemethod of sending a pulse thatstill gives you acceptable resolution.And the solution was called . Bysending a longish linearly sweptpulse out and then by routing thereceived swept waveforms through a

(afancier example of a correlator), theindividual bits and pieces of that sweptwaveform would and generatea narrow target pulse.

The exotic radar systemseven went one step further, especiallythose that were side looking. Theswept transmitted chirp pulses weresuitably recorded, generating whatwere known as .These phase histories were convertedinto viewable data by using lineardelay-vs-frequency networks, opticsthat made a ,holography techniques, or electronicdigital correlators. All of these do acorrelation in one manner or another.

Chirp may sound really complexand hairy. But bats have done it foreons. Compactly and elegantly inwetware. And the bat’s "figure ofmerit" for their radar beats out our bestand newest military radars by someten orders of magnitude. That’s

. And not half bad foramateurs.

But, in all fairness, they did have ahead start.

From time to time in the past, wehave looked at the newmethod for making printed circuitboards. The new direct toner methodpromises to revolutionize hacker pcboards, doing the job in minutes for

GPS

5 100

FM

10,000,000,000:1

Schottky

synchronous rectifiersresolution

width rangepulse area

long

chirp

linear delay vs frequency network

pile up

coherent

target phase histories

Fourier Transformation

direct toner

Printed Circuit Update

54.5

August, 1992

DIRECT TONER PC RESOURCES

Riddle Pond RoadWest Topsham, VT 05086(800) BLACK99

3535 Stillmeadow LaneLancaster, CA 93536(805) 943-4746

Riddle Pond RoadWest Topsham, VT 05086(800) BLACK99

630 Axminister DriveFenton, MO 63026(800) 325-3878

12741 E Caley Ave #130Englewood, CO 80155(800) 843-5277

Box 497Northport, NY 11768(516) 757-3385

111 E Drake Road Ste 7041Ft Collins, CO 80525(303) 491-9092

101 Granite Street Ste FCorona, CA 91719(714) 371-8288

101 Granite Street Ste FCorona, CA 91719(714) 371-8288

45 J. Ringo RoadRingoes, NJ 08551

Black Lightning

DynaArt Designs

The Flash

Kepro

Lazer Products

Meadowlake

Midnight Engineering

Recharger

Supplies Unlimited

Techniks, Inc

pennies with zero darkroom work orother special techniques.

The two key secrets to the directtoner method are that a laser printertoner does make an outstanding etchresist; and that the great PostScriptcomputer language makes printedcircuit layouts exceptionally fast, funand easy to do. From computer,using nothing but your favorite wordprocessor.

One early transfer film sheet wasthe film from .Sadly, many hackers swore at this newproduct, rather than by it. Even thoughmany of the partial transfer problemswere caused by improperly cleanedboards, not doing a preetch or preheat,by using any old copier (instead of aSX laser printer), and trying to use aniron (instead of a Kroy Kolor machineor suitable heat press of some sort).

As we saw last month, a very muchimproved transfer film is now offeredby as their .Both these products suffer a commonflaw: They both expect a

to take place reliably in thereal world. You first ask all of yourtoner to loosely stick to the transferfilm. Later, you expect all of yourtoner to strongly adhere to the board,leaving zero residue on the film.

The differential transfer problemhas been solved in spades by a brandnew offered by

. The system isbasically a polyester film coated withsome high tech sugar water. There aretwo different ways you use the film,called the and the

. Both methods open all sortsof new hacker opportunities.

The hot method is best for hackercircuit boards. With the hot method,you will laser print a backwards butpositive image by using an printerwith a good grade of graphics refilltoner. As with the previous films, youthen iron the toner onto a super-cleanbare printed circuit board. You nowhave toner that is very tightly stuck to

the pc board and the film.Soak your board in warm water for

a few minutes, and all the high techsugar water dissolves,

. And leaving prettynear all of the toner on your circuitboard nearly all of the time. Gentlywash in warm water to remove anyresidue. Then etch as usual.

The cold method is best for circuitboard component callout overlays,dialplates, and ordinary decals. Printyour normal and positive image to thefilm. Then spray your image usingseveral light coats of a clear lacquer,urethane, or epoxy. Cut out all yourimages slightly oversized and soakthem in warm water. Then transferyour images just as you would anymodel railroad decal. You can eitherremove the lacquer with alcohol to get at the bare toner, or add additional andmore protecting clear sprays for extradurability.

Those cold method results do lookespecially impressive when you use a

color copier. Note that you cannow transfer toner onto . Thecost of is five sheets for .

As this month’s resource sidebar, Ihave gathered together a few of thebetter known direct toner resources.Besides the three films we just lookedat, is your leading source ofhacker printed circuit supplies. Moreon the direct toner method is likely toappear in or in

magazines. My two veryfavorite toner sources remain

and , whileothers advertise in the and

magazines.I’ve recently posted my shareware

PostScript printed circuitry layoutpackage over to as ourfile . Plus a newsummary tutorial on the new hacker

printed circuit techniques as file. And new stuff on toner in

general as .

Two reliable sources for foreignsemiconductor replacements are now

and. Both have free catalogs

available on request.A free video on laser printer repair

training is now available from. Don is highly regarded as

having finest training services inthis field. Besides stocking most of thehard-to-find replacement parts.

Two environmental trade journalsare and

. The latterhas plenty of ads for interesting andunusual sensors.

For lots more info on Santa ClausMachines, check out the brand newstereolithography user’s group up on

. And a good tutorial onwavelets has appeared on page of

for April .Two free software sources for this

month: has a freedemo diskette on their newfractal decompression software. And

has a new freebie disk available.

If you are at all interested in activefilters, also be sure to check out myclassic . This isavailable by itself or as part of my

.

TEC-200

PCBF-1000

SX

$9.95

PSRT#401 PRNCRCT.GPS

#419NUTS3.PS

#435 TONERTRX.PS

UNIX16

1992

any

MeadowLake

Technics Inc

differentialtransfer

Toner Transfer SystemDynaArt Designs

cold method hotmethod

both

floating awaythe backing sheet

Canonanything

Kepro

The Flash MidnightEngineering

LazerProducts Black Lightning

RechargerSupplies Unlimited

GEnie

MCM Electronics ConsolidatedElectronics

DonThompson

the

Environmental ProtectionPollution Equipment News

GEnie

Dr. Dobbs Journal

Iterated Systemsreal time

Burr-Brown ActiveFilter Design

Active Filter Cookbook

Lancaster Classics Library

New Tech Lit

54.6

Hardware Hacker

Don Lancaster’s

Hardware HackerSeptember, 1992

Electronic halftonesApple’s PhotoGradeConsultants networkTwo great new booksMarketing your ideas

55.1

Fig. 1 – A LASER PRINTER can fake a halftone by grouping dots into a larger"cell". In this example, a 3 x 3 pixel array forms a cell that can have ten graylevels, including black and white. On a 300 DPI printer, this would form a "100line, 0 degree" halftone screen.

Oh, the times, the times theyare a-changing. We seem tohave a mix of really bad andreally awesome stuff coming

down lately. Let’s start off with someof the sadder vibes…

has recently discontinuedproduction on most of their electronickits. The end of an era for sure.

– A funky little outfit called is setting out to stock

and make available all of those olderHeath assembly books and instructionmanuals. And lots of exciting hackerkits are newly being made availablefrom such outfits as , ,

, and . Plus, ofcourse, through several of our fine

advertisers.The technical paperback book field

(especially the non-computer titles) isclearly not well. is essentiallygone, triaged into the most etherealshadow of what once was the mostrespected and diversified technicalbook publisher in the world. hasgotten itself both conglomerized andthree-piece suited. And I have beengetting plenty of helpline complaintsover several other sources that offerdated, foreign, and inaccurate titles.Believe it or don’t, your is now

.Especially old technical paperbacks.In sort of the same way farmers arepaid not to grow crops. Through anobscure inventory ruling which hastotally decimated long term back listsand older technical titles.

– An incredibly exciting newopportunity calledpublishing is emerging in which youcan produce first quality paperbackand hardback books literally on yourkitchen table

. With a "forever" backlist, no inventory penalties, and no lower

limit to your total number of sellablevolumes needed. And including suchexciting possibilities as a percentauthor’s royalty and rapiddistribution.

Much more on this on .For starters, download our two files

and .

Very alarmingly, some communitycolleges are outright eliminating theirelectronics departments. Or else aresharply cutting back on them. Andmany of those electronic service andrepair trade journals have nowvanished without a trace.

– We now have got the richestand most incredible variety of cheapnew chips to play with. Anywhere.Ever. We have major breakthroughs inhacker direct toner printed circuits.We have got a brand new

format with new features andfresh ideas that continues the oldestongoing electronics publishing house.And we are something like a scanteight years away from hardware thatcan surpass the human brain in logicand analysis capabilities.

Right now is certainly the greatesttime to be getting into hardwarehacking in a big way.

I’ve recently been playing aroundwith the new and am

impressed with its new ability toprint medium- to high-quality photohalftones. So, I thought we mightreview what is involved in the laserprinting of photos in general. And seejust why Apple’s neatprocess seems to elegantly beat out thebrute force methods.

And how we can do even better.

Many of those previous generationlaser printers were devices,capable of placing or not placingwhole dots per inch uniformly alongany one selected laser scan line. Thistranslates up to dots per squareinch, or a tad over million dots on astandard page. If a dot is only black or white, it can usually be represented onthe or else in the

as a single bit. Thus, around amegabyte worth of memory must bereserved for your full page bitmap at

resolution.The obvious big dilemma in raising

your laser printer resolution is this: Asyou go from to , youcould end up requiring timesthe memory! And your page makeuptimes could end up aslong! Yet "more" resolution is clearlyperceived to be a big user need.

Or is it?Actually, laser printing resolution is

pretty much as highly overrated as trucks or teenage sex. But

that’s another story for another time. Istrongly feel that higher resolution isnot worth losing genuine Adobe LevelII PostScript, duplex printing options,low cents per-page printing costs,mainstream technology, useful thirdparty supply sources, local hard disksupport, or any sleep over.

At least for most people most of thetime. And a poorly scanned photo (or

Heathkit

Musty Manuals

PAIA ElectorOld Colony Micro Mint

SAMS

TAB

paying all publishers to shred books

Book-on-demand

when and as they areordered

GEnie

eververy

LaserWriter Gvery

PhotoGrade

page bitmap framedevice

sixteen

sixteen times

Peterbilt

BUT

IRS

BUT

IRS

90CD ROM

PSRT

DEMAND.TXT DEMAND.PS

BUT

300 DPI300

90,0008

300 DPI

300 DPI 1200 DPI

0.2

Electronics Now

ElectronicsNow

Electronic halftones

55.2

Hardware Hacker

Fig. 2 – THE AVAILABLE SPOT PATTERNS for a typical 300 DPI PostScriptprinter. Note that these are the ONLY dense patterns available. You’ll get oneof these regardless of what you ask for. Also note the perfect tiling.

49 SPI, 10 degrees39 grays






















one that is not properly) could end up looking even

on the premium machines.One zero cost way to increase your

printer’s resolution when you’d like"camera ready" art for conventionalprinting: Just work oversize and thenphotoreduce. Most of my

figures are run at percentnormal size, thus giving an effectiveresolution of a scant . Yet Ifeel they look as good as most of the

other technical figures.An easy way of making a

printer look better is to do a plain oldsmoothing. Which was pioneered by

as their.

Apple (and many also-rans) havecopied this idea. On the LaserWriterG, Apple calls it .

The smoothing is done by a customintegrated circuit that intercepts andstores a few of the scan lines on their

final way out to the laser scanner. Byanalyzing a matrix formed from thenearby dots on earlier and later lines,certain dot positions are delayed byone-half a dot, following a smoothingalgorithm. Which results in a reallybig improvement in most typographyand some graphics, escpecially for anyslanty lines.

Despite all of the hype, the circuitryinvolved is simple and cheap. And itcan end up totally independent of theimaging model or language in use.

But plain old smoothing can’t helphalftone photos any. And may evenhurt. Let’s look further at…

There is only one method to printsomething that is truly gray on thepage. And that is to use gray ink. Andeach shade of true gray willneed a gray ink and anotherpass through the printing press. Sincethis is clearly ungood, printers havelong used a process instead.

The halftone process consists ofprinting lots of different sizeddots very near to each other. The dotsare carefully spaced to be below theeye’s angular resolution. Instead ofseeing the individual dots, your eyeaverages out the black dots and thewhite background and perceives anaverage gray level. The higher yourratio of white to black, the lighter thegray, and vice versa.

Let’s try it. Now, this might looklike it is gray…

But get out your magnifying glass,and you’ll see all the little black dotsused for this line .The dots are all black.

To print any photograph, a specialscreen is used on the litho camera toconvert grey values into collections ofblack dots of varying size.

Traditional printers will spec their as the number of halftone

spots per inch. Some popular finalscreen frequencies include spotsper inch for tabloid news and thespots per inch for most magazines of

quality.Even higher spot densities get used

on premium magazines. But these dotake special inks, coated papers, andextreme attention to detail.

histogramequalizedworse

HardwareHacker

Hewlett Packard ResolutionEnhancement Technology

FinePrint

differentdifferent

halftone

black

halftone screen

screen size

Electronics Now

133

400 DPI

300 DPI

106

85120

The halftone process

55.3

September, 1992

Fig. 3 – THE TOP SECRET GRAY MAP for a 300 DPI PostScript printer. Mostusers and most application packages insist on using the seventeenth mostputrid of the available grays. The "best" graphics gray is 106 DPI at 45 degrees.

Scr

een

den

sity

in

do

ts p

er i

nch

2

3

5

6

9

10

11

14

19

17 18

26 26

27 30

3537

21

33

39* 42* 42*50

55

60

65

70

75

80

85

90

95

100

105

110

115

120

125

130

135

140

145

150

175

210

300

number of graylevels, includingblack and white,for each region

0 5 10 15 20 25 30 35 40 45

Screen angle in degrees

A second halftone parameter getscalled the . It turns out thehuman eye is very good at picking outhorizontal and vertical lines, but ratherpoor on resolving diagonals. Since thehalftone process can introduce

, it is often best to set yourblack and white screens on a degreeangle. In color printing, the halftonescreen angles can become even morecritical if they are to eliminate mostobjectionable patterns.

There are several methods to fakehalftone screens on the laser printers.One is to group all the possible laserdot positions into larger spots that I’llcall a . Figure one shows you howa printer can use nine dots tomake cells of spots per inch. Thisparticular cell has a screen angle ofzero. As you can see, there are tenpossible gray levels here, includingblack and white.

We can immediately see that wecould use thirty-six dots to formspot per inch cells. And these cellswould give us thirty-seven possiblegrays. Clearly, we do have a tradeoffbetween the number of cells per inchand the number of available grays.Use too few cells per inch, and you’llget the "Sunday Funnies" effect withvery grainy dots. Use too few grays,and you will with obvious(and often objectionably bad) stepsbetween each possible gray level.

The gray level resolution of youreye depends on context and contrast,but something slightly over graylevels is often possible. But, becauseof the stupendous costs of exceeding

grays, most experts agree thateight bits of gray scale resolution is"enough" for even the most premiumimages. Television sometimes mightget by on as few as six bits, good for a mere gray levels.

The obvious next question is "Howgood can our halftones image at anunenhanced resolution of ?"Ignoring the obvious answer of "Notgood enough", we’ll then go on to ask"What can we do about it?"

I’ve discovered that thegeneral purpose computer languagehas some really great approaches to

electronic halftones. These do involvetheir and operators,among many others. PostScript usessome imaging that determine thescreen angles and frequencies. Sincethese screen tiles must all abut eachother perfectly and still must followinteger (whole numbers only) math,

there are very definite limits to which tiles are possible.

If you ask for some halftone cellangle or frequency that is simply notphysically possible, PostScript willsubstitute the nearest handy one.

Figure two shows you the availabledenser halftone cells as used on most

Note that even the very highest spotdensities used are nowhere nearspots per inch!

screen angle

visualartifacts

Moire

cell

solarize

PostScript

setscreen image

tiles

45

300 DPI100

50

256

256

64

300 DPI

300 DPI300

PostScript to the rescue

55.4

Hardware Hacker

Fig. 4 – BOTH QMS AND IBM/LEXMARK chose the "brute force" 600 DPImethod to improve their PostScript photo halftones. The original 100 DPI spotsallowed 10 gray levels; the new ones allow 37. There is a 4X speed and 4Xmemory penalty for the modest (but certainly welcome) improvement.

old 300 DPIpixel size

new 600 DPIpixel size

(100 DPI, 0 degree halftone cell shown)

popular PostScript printers.Figure three shows you the

for all of the "hidden" PostScriptgrays you can use.

Typical PostScript users and mostapplications packages blindly insist onchoosing the most putridPostScript gray available. While this isoften incorrectly labeled ascreen, its effective resolution is only

dots per inch. There are grayswith this default screen.

Which sort of explains the "SundayFunnies" effect of most poorly donePostScript screens. And one of thebiggest reasons why people feel theyneed "more" resolution. When in fact,their grays could all get instantly anddramatically improved by using a fewdozen keystrokes!

Ferinstance, the "best" PostScript halftone screen for typical

graphics is a , degree onewhich gives you absolutely beautifulgrays. Sadly, you’ll only get ten ofthese grays, but the lightest ones arevery good for graphics.

Two other quite usefulsecret PostScript grays of interest arethe line and degree "reprogray"useful for oversize camera ready art,and the line, degree "india inkwash" gray. The latter gives you onlysix gray levels and requires a carefulselection of toner and paper. But theresults are stunning.

For photo halftones, you might like

to try the spot and degree screenhaving eighteen grays. Or else thespot, degree screen with nineteengrays. Using an amount ofcare, these can become just barelyuseful in certain applications.

No, none of these screens can giveyou any high quality halftone photos.But the line screen can give you arecognizable "auto shopper" qualityphotograph. Especially if the scannedimage has been properly histogramequalized.

One way to do a "best" PostScriptgray is to enter these keystrokes asPostScript commands…

The very first number is your cellfrequency; the second is your angle.The details of where and how youenter these code lines depend on yourPostScript programming style or theapplications package.

Call me if you need any further helpon this.

We may see quite a bit more onimage enhancement next month.

Three key points: The halftone dotsused in everyday printing are

than . Some excellentgraphic PostScript grays are availableat that only need a few dozensimple keystrokes for their activation.And our halftone photo quality,

,

doesn’t miss by that much.So we can potentially add only a

little to and gain enormouslyon halftone photo quality. Bothand picked the bruteforce method. As figure four shows us,they switched to a doubleresolution and then swallowed thespeed and memory penalties. Atcells per inch, you now have graylevels. Or gray levels at an cellsper inch density.

Which could makes the differencebetween "lousy" and "not half bad"photo halftones. Especially given aproper digital image processing.

Apple has chosen the more elegant method of figure five.

They remained at , but addedthree extra bitmap memory planes fora total of four. Then they modulatedtheir laser dot size to one of sixteenvalues. You now could havetimes as many potential gray levels asyou did at with only a singlememory plane. At , you nowhave a much better gray levelsavailable. Which is equal to a bruteforce resolution of

There is only a negligible speedpenalty, since all four memory planesare written in parallel using custom

chips. And while you retain thesame memory penalty as a bruteforce , you’ll getthe effective resolution!

The results? Good to better photohalftones out of any plain oldlaser printer engine. Especially withpremium toner and properly scannedimage processing.

The PhotoGrade is also upgradableon older and printers with asimple plug-in board swap.

I think we can. At least in theory.For any spot per inch tile at plainold , we are using bits tocall out only different spot values.Since nine bits could representdifferent state values, the

is a tad under two percent.Wowie gee.The does ridiculously

worse. Here we are askingbits to call out a mere differentgray levels. Since thirty-six bits canyield us up to differentstates, our memory use efficiency isessentially !

secret graymap

seventeenth

extreme

106 45 dup mul exch dup mul add 1.0 exch sub setscreen

muchcoarser

whengiven properly image processed input

QMSIBM/Lexmark

PhotoGrade

sixteen

four times

nine

memory useefficiency

PhotoGradethirty-six

zero

300 DPI

60 DPI

53 33

300 DPI106 DPI 45

300 DPI

85 35

135 25

73 1471

45

71

300 DPI

300 DPI

300 DPI

600 DPI4:1100

3750 85

300 DPI

300 DPI106 DPI

128

1200 DPI.

LSI4X600 x 600

300 DPI

NT NTX

100300 DPI

10512

144

68,719,476,736

Can we do better?

55.5

September, 1992

PRODUCT MARKETING RESOURCES

7401 Fullerton RoadSpringfield, VA 22153(703) 866-2000

835 Penobscot BuildingDetroit, MI 48226(313) 961-2242

401 North Washington StreetRockville, MD 20850(800) 638-9636

1683 Plymouth RoadAnn Arbor, MI 48105(313) 663-8000

4 Park Street, Suite 20Vernon, CT 06066(203) 875-2751

111 E Drake Road Suite 7041Ft Collins, CO 80525(303) 491-9092

3200 Teakwood LaneEdmond, OK 73013(405) 340-6300

17371-A1 NE 67th CourtRedmond, WA 98052(206) 882-2009

Box 809Thatcher, AZ 85552(602) 428-4073

27 Gate Five RoadSausalito, CA 94965(415) 332-1716

DesignTech International

Encyclopedia of Associations

GEnie

Inventor-Entrepreneur Network

Micro-Mint


PAIA Electronics

Redmond Cable

Synergetics Consultants Network

Whole Earth Review

Thus,

Instead, let’s go back to, say,spots per inch at a plain old .Once in the of every desiredhalftone spot, put out a laser dothaving up to possible size values.Presto. A mind-blowing total ofgrays at ; Or a "perfect"grays up at the usual

What would happen is this: Thelaser scanner would run in one of twoselectable modes. In the

mode, the dots go down atthe expected resolution. In the

mode, fewer and much largerdots go down at the expected halftonescreen resolution.

Even if an entire bitmap was neededto keep track of modes, this would stillbe up to as memory efficient asPhotoGrade, while still delivering upto four times the actual number ofresolvable photo grays.

But a simple old mode list couldpossibly be used instead. Yielding a

memory penalty for top qualityphoto halftones.

This for photo halftone dots only;you would still be able to do specialscreens and weird spot functions theold way. Patterns, too.

Note also that your laser printerwould now be doing variable sizeddots in exactly the same manner that"real" printing halftones usually godown on the page.

For us to fully utilize what seemstheoretically designable, you wouldneed some special automatic modesensing for the halftone areas. And adiamond-shaped laser beam whosediameter can be controlled over adecibel or range. Down from amaximum slightly under three times

than now gets used. None ofthese needs seems a really big deal.

Thus, it should be theoreticallypossible to build a PostScriptlaser printer with outstanding photohalftones. A equivalent. At

speed or memory penalties.Hmmmm…I have posted lots of halftone and

secret gray study examples to, especially in my files

and I’ve alsouploaded some high quality imagesthat you can play with, either inside oroutside PostScript. In particular, check

out , , and myenhanced .

I was pleasantly surprised that theleading invention marketing firms arenow publishing their track records. Upfront in their initial mailings. One ofthe oldest and largest discloses: Of theideas submitted and contracted, theodds of getting a royalty license are

against, and the odds of anypositive cash flow that exceed costsare against.

These figures sound about right tome. Sometimes I’ve done almost thatgood on my own. And sometimes not.Selling an idea is a real rough row tohoe. One that could become a nearimpossibility if you are not a fullytrained and well experienced insiderattuned to the trade journals, politicalrealities, seminars, economics, andtech literature of the target field.

An invention marketing firm is justa hired gun, similar to an ad agency ora resume typing service. You pay themfor their time and effort. For suchservices as patent searches, for listingsin product newsletters, and promotionat invention fairs.

Cash up font.Naturally, asking anyone at any

invention marketing outfit whetheryour idea has any value is about asbright as asking any auto salesman

whether you need a new car. Or an adagency whether you need an ad. Or amugger whether you need mugged.Come on now. What did you expectthem to say?

As we’ve seen a number of times inthe past, the core problem lies in theabsurd mythology surrounding today’spatent system. Very simply, patentshave little to nothing at all to do withthe selling or marketing of an idea. Formost individuals and most small scaletechnical startups,

.Just about all hackers will tend to

grossly overvalue a new idea. At onetime way back in the golden age ofinventing, ideas were occasionallyworth as much as one dime a dozen.Today, they are worth less than tencents a bale in ten bale lots. Any ideasgain value when you can clearlydemonstrate your end users actuallygetting off on them. And thenwhen those ideas are in somesaleable, competitive, promotable, anddistributable form.

The key secret to selling an idea isvery simple:And vice versa. For our specialresource sidebar this month, I havetried to gather together a few usefulalternatives that can help you profitfrom your ideas.

virtually all of that ApplePhotoGrade memory bitmap is totallywasted!

centersingle

normalPostScript

photohalftone

twice

zero

larger

zero

GEnie

any involvementwhatsoever with the patent system isvirtually certain to end up as a net lossof time, energy, money, and sanity

only

onlyalready

They must come to you.never

100300 DPI

512512

100 DPI 256106 DPI!

2516:1

300 DPI

1697 DPI

PSRT 129, 141,144, 179, 180, 231, 239.

LENA.PS MANDRILL.PSLENAHIST.PS

100:1

600:1

Marketing your products

55.6

Hardware Hacker

Fig. 5 – THE APPLE LASERWRITER G remains at 300 DPI, but uses fourbitmap memory planes that allow one of sixteen pixel dot sizes. This permits144 gray levels at 100 DPI for good- to better-grade photo halftones. Or 128gray levels at the more popular 106 DPI and 45 degree screen.

"8" bitmap "4" bitmap "2" bitmap "1" bitmap

4-bit D/A converter

(100 DPI, 0 degree halftone cells shown)

One-of-sixteen dot size output to laser scanner

Two essential magazines are that and the

. There are bunches ofindependent and non-profit inventor’sorganizations out there. One I canheartily recommend is Ed Zimmer’s

. Forother regional sources, check out the

you willfind at your local library.

No, I just do not know of anyoneanywhere that is dumb enough to buyraw, unproven, or undeveloped ideas.But I do know of several someoneswho sometimes may be interested inlooking at tightly targeted products

.For instance, Mark Gottleib of his

is lookingfor innovative approaches to low endconsumer electronics, especially forthose items that can be blister packedand need no smarts to use.

Dennis Carper of isseeking out tested and already proveninterconnect and adaptor products thatcan clearly solve some obvious andwell defined problems.

John Simonton of sometimes

looks for items with kit possibilities,especially if they are related toor electronic music.

And Steve Ciarcia of his is occasionally interested in any

embedded processor aps. If they aregenuinely unique.

Once again, please don’t hassle anyof these folks unless you are well intoa real world beta test. And then makecertain it applies to them.

Besides my own RoundTable, you also just might want to

check out their , short for.

I’ve also more or less put togethermy ongoing, loosely knit

that centers onour voice helpline. There’s no chargefor referrals to a consultant in our database. If you are a consultant and wantto participate, there is a five percentreferral fee, due when and as the workis actually completed and collectedfor. And out the door.

Give me a call at ifyou need any more info. Best callingtimes are weekdays, in

.

From , seven

pounds of revised linear data books.Volume on op amps; on , ,and video; and volume on voltageregulators and really oddball stuff.

A pair of very readable new books:

, by Jerome Markowitz,of , and published by the

. Among the otherthings, it reveals how trivially easy itis to have any technically solid andperfectly valid patent busted in court.Just because some epsilon minus doesnot happen to like you.

Plus by thepseudonym , andnewly published by .Subtitled

. This book has a double handfulof quite funny one-liners in it. Butotherwise reads like something thatCringley would write.

I’ve found few trade journalsavailable on electronic servicing. Oneuseful new one, though, is

. Abig emphasis is on computer service,especially handy sources for printerand disk drive replacement parts andassemblies.

A great collection of navigationbooks, and otherwise is offeredby the .And a newlabor-of-love newsletter has recentlystarted publication.

Two additional firms apparentlystill offer top octave generators andother classic electronic organ chips.The first is ,and the other isThe latter also builds workaroundreplacement modules for chips that aretruly unavailable.

Turning to some of my very ownproducts, yet another obvious andmajor product selling resource is myrecently improved

. The autographedcopies are available per my nearby

ad.As usual, we’ve gathered many of

the resources mentioned together intothe appendix orinto thesidebar. Do be sure to check these out

you use our no-charge techhelpline or calling for a free hackersecrets brochure.

Midnight Engineering WholeEarth Review

Inventor-Entrepreneur Network

Encyclopedia of Associations

ifthese products are already in theirpre-production prototype stage andare currently under active end userbeta testing

Design Tech International

Redmond Cable

PAIA

MicroMint

on GEnieHome

Office and Small Business

SynergeticsConsultants Network

MountainStandard Time

Texas Instruments

The Triumphs and Trials of an OrganBuilder

Allen OrganVox Humania Press

Accidental EmpiresRobert X. Cringley

Addison WeseleyHow the boys of Silicon

Valley make all their millions, battleforeign competition, and still can’t geta date

very

MSM, theMagazine of Service Management

Navtech Information ServiceSpread Spectrum Scene

Fistell MicroelectronicsKeyboard Systems.

Incredible SecretMoney Machine II

Synergetics

Names & NumbersProduct Marketing Resources

before

MIDI

PSRT

HOSB

(602) 428-4073

8-5

I II A/D DSPIII

CEO

GPS

New tech lit

Don Lancaster’s

Hardware HackerOctober, 1992

Alternate action latchesHistogram equalizationGamma curve correctionDigital image processingSemiconductor ic houses

56.1

Fig. 1 – SOME SIMPLE LATCHESand alternate action circuits.

(A) Relay converted to latch.

Set

Clear

+V+V

(B) Inverter pair used as latch.

R

SetClear

10K

10K

(C) Alternate action pushbutton.

22K

470K

0.1 FChange µ

Stop the presses. hasjust announced apiezo gyroscope. Which, if itis as great as it looks, could

easily become hacker componentof the decade. All I’ve got on this sofar is that brief note in the June 8th

and a promise for moretech info. Needless to say, the hackerpotential of a nav gyro would betruly revolutionary.

Be sure to stay tuned on this one.Things are also starting to happen

fast and furious on that direct tonerprinted circuit board front. Since mylast report, the new and water solubledecal basedoffered by has been furtherimproved. The new

fromlooks even more promising.

What Techniks did was take theirold differential transfer system andadd a new and blue polymeric releasecoating. This poly release coating candramatically improve the transfer andactually becomes an important part ofyour resist pattern.

Every week or so I get at least oneletter or a helpline call from someonewho feels they have clearly brokensome physical laws. Maybe they haveproof that the speed of light is not aconstant. Or that those three laws ofthermodynamics just do not apply tothem. Or that perpetual motion can bepossible using magnetic repulsion. Orthey have tapped the zero point scalarenergy from the fabric of space. Orthat their latest pet theory proves thecold fusion process.

Usually, they’ll also complain thatthey’ve sent their theory everywhereand have gotten zero replies. Or thatthey are getting ignored because theyare an outsider.

Very often, their inquiries will beself-defeating. How? By includingtotally irrelevant religious or politicalcontexts. Or by being super secretive.Or written and submitted in such away that they scream "Hey, kick me,for I’m not even computer literate."

If it likes water, looks like a duck,and quacks like a duck…

But consider who is receiving theseletters. Based on past experience, theeditors or the publishers that theprobability is that the lab work(if any) is just plain wrong. Or, moretypically, . Andthat the sendee is clearly a few chipsshy of a full board. Why theybelieve you?

The sad thing is that needle in thehaystack. I’m going to be generousand claim that one letter in in fact

have the germ of a new theory ora developable product or a fresh lookat a solvable problem. And, yes, newerideas often get ignored or vehementlyattacked.

What can you really do if you havegenuinely beaten those overwhelmingodds and your controversial idea is infact both new and for real?

There are two possible routes youcould take to get your ideas accepted.The first or method is to

. Be sure to use lots of carefulresearch, especially throughand those reprints. Be certain tosubscribe to of the relevant insidertrade journals and go out of your wayto study the scholarly publications inthe field. Learn all the lingo. Attendconferences and trade shows. Find apatient and knowledgeable industryinsider that is willing to look at youridea and honestly comment on it.

.Hire some competent engineering

or physical science consultants tostudy and add credibility to all yourclaims. Do take enough college anduniversity level courses to make sureyou do thoroughly understand at leastthe fundamentals of the field. Alongwith the needed math to back it up.

And finally, you present the ideasclearly identified as a possible newtheory in some professional contexttotally free of religious, political, orany conspiracy mumbo jumbo.

The second route is to publish via a press. There are quite a

few of the underground or alternatelife publications that welcomematerial of this type. Every now andthen, that givesyou a list and rundown of all themagazines of this genre. Let me knowif you want to see a resource sidebaron these.

One leading bookstore that doesspecialize in selling and distributingpseudoscience topics is

. Many of their offeringsare utterly fascinating. These folksalso do sponsor several yearly forums

MurataGyrostar

the

Design News

Toner Transfer SystemDynaArt

Printed CircuitBoard Transfer Film Techniks

know

not even wrong

should

does

real sciencethoroughly try and prove that you arewrong

DialogUMI

all

Make absolutely certain that youhave a simple experiment that can beindependently duplicated and verifiedby disinterested outsiders

pseudoscience

Whole Earth Review

High EnergyEnterprises

$5

0.99+

0.99+

500

Faster than the speed of light?

56.2

Hardware Hacker

Fig. 2 – A DIGITAL IMAGE is nothing but an array of numbers. Digital imageprocessing takes those numbers and replaces them with other numbers,following a rule or set of rules. While there is a stunning variety of uses fordigital image processing tricks and techniques, two of the most importantinvolve gamma correction and histogram equalization.

119 023 126 194 091 086 ... 004

032 093 170 079 093 106 ... 115

083 205 001 240 032 089 ... 093

101 223 115 216 015 041 ... 251

... ... ... ... ... ... ... ...

080 128 219 129 177 161 ... 253

107 206 035 000 193 254 ... 091

The at each or picture elementdetermines the brightness for that pel; the

of that pel in the array setsthe pel position in your actual image.

VALUE PEL

LOCATION

where the controversial pseudosciencetopics are strongly encouraged.

Several important tips whenpublishing your own pseudosciencetracts: Be sure to use cut-and-pasteXerox-of-an-Xerox and lots of poorlyprinted sloppy layouts. Smeared inkon cheap paper is a must. Be sure tofreely quote obscure rural newspapersas your prime data sources. Do becertain to include illegible artwork.Extensively refer to unheard-of andunavailable journals. Use plenty ofirrevelant inference and innuendo.

Be sure to use only year oldreferences, especially in any rapidlychanging field. Misquote and dropsome big names, even if totally out ofcontext and they never heard of you."Billions and billions of Carl Sagan’sago..." offer any succinct andeasily verified experiment.

Always use ten words where onewill do. Make all of your paragraphsunbearably wide and long. Then runthem all together in haphazard order.

come right out and state yourkey points. Work Tesla in somehow.Be sure to include plenty of obscurereligious and/or political references.Show how your theory is now beingsuppressed by a federal conspiracyheaded by the Trilateral Commission

and secretly funded through both the and the .

Ignore all the personal computersentirely. They are only a passing fadthat never will catch on. Finally andabove all: Do not ever, under anycircumstances, use any new desktoppublishing tools and techniques.

I got a helpline call the other dayasking for a circuit to convert any oldordinary relay into an alternate actionon-off device. Well, as the caller hasfound out on his own, that gets a littletrickier than it sounds.

Figure does show you how toconvert a regular relay into a latchingrelay. Press normally open buttonand your relay pulls in. The pull incloses a relay contact that yourrelay engaged. To reset your relay,press normally closed button . Therelay drops out, opening its latchingcontact. This is a simple example of a

, or a flip flop.In we’ve used a pair of digital

logic inverters instead. An inverteroutputs a one for any zero input andvice versa. Assume the left inverterhappens to be outputting a one. Theright inverter sees this one as an inputand outputs a zero. The zero in turn

reaches around and holds the leftinverter in its present state. We arethus latched and stable. Press buttonto set your latch. Press button toclear your latch.

It does turn out that any alternateaction circuit has to consist ofdistinct storage elements. One is for"Where am I?" and one is for "Wherewas I?" If you fail to provide for twostorage devices, you are to getinto major reliability, oscillation, orpreferred state hassles.

In most integrated circuits, the twoneeded storage elements are done witha of separate latches. One getscalled the flip flop. The other isthe flip flop. Often these arecombined into a single more complexlogic block, forming a

or some similar device.Check carefully, and you will even

find your button on a retractable ballpoint pen to consist of two distinctstorage devices.

The simplest and the most elegantalternate action pushbutton I know ofappears in figure . The "Where amI?" storage consists of that pair ofback-to-back inverters. Your "Wherewas I?" storage is the capacitor.

Here’s how it works: Some brieftime after that latch changes, yourcapacitor will charge up to hold the"Where was I?" one or zero. Pressingthe button forces the "Where was I?"value back onto the input of the firstinverter, and the latch quickly flips.

This happens because the charge onany capacitor cannot immediately bechanged. Thus, at the instant yourswitch is closed, the capacitor acts as avery low impedance which "forcefeeds" its value to the inverter input.As soon as the inverters flip, positivefeedback holds your new value.

Releasing your button will let the"Where am I?" pair of inverters worknormally. A short interval later, thecapacitor will charge up (or down) toits new "Where was I?" value, and thecycle can be repeated.

This circuit can also be used as arelay driver. It’s the fastest and bestway I know of to make a mechanicalrelay reliably alternate its states.

While any old gates could beused, my favorite here would be a

hex Schmidt Trigger.Much more tech info on counters,

latches, and state alternation appears

very

Never

Never

holds

latch set-reset

two

certain

pairmaster

slave

type-D clockedflip flop

20-200

WCTU SPCA

1-A

A

B

1-B

AB

1-C

CMOS

74HC13

Alternate Action Pushbuttons

56.3

October, 1992

Fig. 3 – THE GAMMA CURVE for any display or printer relates how thebrightness levels are viewer perceived compared to how they are input. Anon-linear gamma either "muddies the lows" or "washes out the highs". Gammacorrection attempts to make each gray equally significant to the end viewer.

Intended gray levels at input

Perceivedgray levelsat output

(black)

(white)

C

B

A

C

B

A

Typical Gamma curve of a CRT electron beamdisplay or a "white write" laser printer willwash out many of the lighter whites.

Properly gamma corrected display or printertreats all gray levels equally. Some availablegray levels may be lost in the process.

Typical Gamma curve of a "black write" laserprinter (such as a Canon SX) will muddy thedarker grays.

in my .

I never cease to be amazed at howstunningly versatile that PostScriptgeneral purpose language is. I haverecently used PostScript to create agroup of rapid, easy, and fun digitalimaging processing tools. The toolsand a few test images to go with themhave been posted to myRoundTable as .

What I guess I’d like to do here isgive you a brief intro to digital imageprocessing. We’ll limit ourselves tohigh quality gray-scale images.

We will also try to zero in on doingboth a and a

. These are bothhighly important and little understoodcrucial uses for serious digital imageprocessing. Fail to understand eitherone and your images will all end updisasters waiting to happen.

We’ll first note that good old silverhalide "slopping-in-the-slush" photowork is both incredibly versatile andhighly forgiving. Besides having anenormous dynamic range.

Instead, electronic digital displays,printers, and any photosettersdata which is always "right on". Ifanything misses at all, you will getlousy to useless results. Which is whydigital image processing has becomeso important. And so hackable.

Hmmm. To do some digital imageprocessing, you have to start with adigital image. You can borrow one ofmine off of , or grab onefrom a scanner, off a satellite, a faxmachine, or some live video captureboard. Such a digital image is made upof or . Note that apel may or may not be the same size asthe final on your output device.A pel is defined as the

found in yournumbers within the digital image.

In a gray scale image, a pel getsdefined by three parameters. The pel

value will tell you how this tiny portion of your scene

will be. Its value will tellyou how far in the picture this pelsits, while its tells you howfar .

Ferinstance, in the file on up , we use possible

grays (ranging from PostScript’s =black smoothly up on through a =

white). These pels are arranged as animage bytes wide by byteshigh. This size was picked to be bigenough to be useful and interesting,yet small enough, short enough andfast enough to have lots of fun with.PostScript, of course, can handle anyimage size and resolution you want.

The first byte in your data filecontains the 8-bit luminance value forthe upper lefthand pel. The secondbyte for the next pel to the right, andso on. After horizontal pels, thedata starts over again at the left pel ofthe next line down. This repeats for atotal of lines or bytes.

Or for short.As figure two shows us, digital

image processing simply consists oftaking this large array of digital bytesand then creating a second array ofnew digital bytes. The bytes in yoursecond array are related to the bytes inthe first array by some rule or set ofrules. And your processed new image

should now somehow be "better" forwhatever you are trying to do.

For instance, we might just takeeach individual data value and make it larger. Which would brighten yourdisplay and give you values.Make each data value smaller, and youwill instead your display,favoring darker values.

Should there be any defect in thepicture, you can "retouch" by lookingat adjacent pel values and working out some type of average. And carried toextremes, this style of digital imageprocessing can remove any telephonepoles from pictures, rearrange trees,and literally leap tall buildings with asingle bound.

A digital image processing trickknown as an lets youremove the jaggies from black andwhite lines. For anti-aliasing, greyvalues should get substituted equal tothe expected average value at each pel.From nearly any reasonable viewing

CMOS Cookbook

GEnie

gamma correction histo-gram equalization

demand

GEnie

picture elements pels

pixelminimum

resolvable data value

luminancebright

X positionover

Y positionup and down

lighter

darken

anti-aliasing

PSRTIMAGEKIT.PS

PSRT

LENA.PS#463 PSRT 256

01

256 192

256

192 4915248K

Digital Image Processing

56.4

Hardware Hacker

Fig. 4 – THIS STOCK "LENA" DIGITAL IMAGE appears rather "weak" or "low incontrast". A glance at the histogram clearly shows why. There are no darkblacks, no lighter whites, and the few remaining grays cluster in or around thetwo prominent peaks.

(black) (white)

Gray levels

Graylevel

usage

distance, your jaggies will magicallydisappear. Poof.

Calculating new pel values basedupon values of neighbor pels opens upall sorts of powerful digital imageprocessing opportunities.

Ferinstance, if you average or lowpass filter against nearby pels, you cansoften or your image. If youemphasize any differences, you cancrispen or your final image.Carried to extremes, a crispening orsharpening becomes ,where only outlines remain. A magicalgorithm called a is oftenused for high quality edge detection.

What if your original picture is outof focus or blurry? Well, you can go toa rather fancy or wavelettransform into a andextract a . Whichcan cancel out much (but not all) ofsuch things as camera motion. Andperform such tricks as reading thoselicense plates on speeding cars.

There are now zillions of exciting

techniques which use digital imageprocessing. We may look at some ofthese in future columns. But the firstof the two techniques I feel are by farthe most important involves…

The eye acts as a log, rather than alinear device. And deep down inside,most display schemes are also quitenonlinear. As figure three shows us,the curve for any imagingsystem relates how the inputgray levels actually to your eyeat the output.

The process of "fixing" a gammacurve gets called .On a video display, nonlinearities are

introduced to attempt tocancel out such nonlinearities as thesquare law response of most electronbeams to a control voltage. In colorwork, the strengths of each individualbeam are also carefully adjusted tomake each color appear to be equallybright. Even if the color phosphors

used have different sensitivities. Asdoes your eye’s response.

If at all possible, you want to doyour gamma correction in some waythat does cut into the number ofgrays you have got available. But if itsimply can’t be helped, digital imageprocessing can get applied to gammacorrect your display. It can do this byredefining gray levels, trading off a lotof nonlinear grays for fewer and morelinear ones.

All of today’s laser printers haveinherently nonlinear gamma curves.This happens because a round dot isused which has to be than theintended square pixel it is supposed tocompletely and flawlessly overwrite.Thus, in a system (such asthe Canon ) where the laser placesdown black dots, typical gray levelsusually end up than you askedfor. Especially the lightest ones.

The system used on theApple uses a digitalimage processing to trade off its graylevels for a more linear gamma. Wesaw some details on thehalftoning process last month. As aspecific example, at , Apple’sPhotoGrade system has graylevels available. A total of of theseare often used for gamma correction.The gamma correction gets done byredefining lots of really dark grays anda few of the mid range grays. The netresult is the remaining distinct andfully Gamma corrected grays.

The PhotoGrade system offers youthree calibration options. The optionscompensate for your particular choiceof toner, density settings, humidity,and so on. On a calibration, a coarseand a finer halftone square are putdown for typical gray levels. This isdone for three different pages. Youthen pick the page you like the best.The internal code does a predefinedGamma correction for you.

Additional details on PhotoGradeprocessing appear in my

and over in. Also quite handy is

a from .

Those photo darkroom techniciansand artists have lots of secret tricksthey employ to explore the incredible

soft focus

sharpen

edge detection

Laplacian

Fouriertransform plane

deblurring function

Gammaexpected

appear

Gamma Correction

purposely

not

larger

black writeSX

darker

PhotoGradeLaserWriter G

PhotoGrade

GEnie

LaserWriter IIg PrintersDeveloper Notes

106 DPI128

61

67

PSRT#451 LASGCAL.PS #388LASGNOTE.TXT

#R023ll/AAPDA

Gamma Correction

Histograms and TheirEqualization

56.5

October, 1992

Fig. 5 – HISTOGRAM EQUALIZED "LENA" DIGITAL IMAGE has considerablymore "snap" and much higher contrast. The histogram shows all gray valuesare in full use. A histo equalization is the same as a perfect photo "dodge andburn". The quality can be further improved by gamma correction.

(black) (white)

Gray levels

Graylevel

usage

dynamic range of most photo film. Bylengthening or shortening all theirexposures, they can make all of theirprints darker or lighter. By printing on a "soft" paper, they can reduce theirdynamic range and contrast. Or canincrease it by using a "hard" paper. Oreven eliminate it entirely with a lithophoto paper.

Even more sneaky is and. With dodging, you put your

moving and out-of-focus hand or a between the enlarger

and the area being printed. This your light in a selected area and

makes that area than normal.Which lets you pull details out of anydark or "muddy" areas of your neg.

With burning, you hold an opaquemask having a small, ragged, out offocus, and rapidly moving hole in itbetween your enlarger and the printpaper. Burning lets you darken yourhighlights and extract details fromunderexposed areas.

By now, most of you have seenthose spectacular Navajo slot canyonphotos. Most any southwest calendarshould include at least one example.And will be happyto sell you bunches of them. Theseincredible prints carry dodging andburning to an extreme, using multipleexposures and twenty or more veryprecisely aligned dodging masks todramatically bring out the subtlities ofcolor and texture.

Sorry, but if you go to the bottom ofone of these slot canyons like I have,you’ll find them to be – mostly dark.What you are viewing on your finalslide or print is highly spectaculardarkroom art, rather than any humanviewable reality.

Digital image processing can beused to imitate these darkroom tricks.And getting things right on gets evenmore important with digital images,because you will always belimited by both the available dynamicrange and laser resolution.

The first step in correcting a digitalimage is to find out what was wrongwith it in the first place. To do this,you run a . A histogram issimply a vote on how many of thegrays get used how often. Figure fourshows us the stock and well known

digital image. If all has gone okwith the prepress opsthat are beyond my control, this photo

should appear slightly "weak" or lowin contrast. Flat.

That histogram underneath Lenaclearly shows us why. Those lightestand darkest grays are not used at all.And most of the rest are bunched intwo clearly defined peaks.

A digital image processing methodknown as willlet you perform a magic dodging andburning which can often dramaticallyimprove your results. If figure fivemade it through prepress the way Ihope it will, you should see a muchhigher contrast and greatly improvedLena with lots more "snap".

To do your histogram equalization,you try and spread all of your pelsaround such that

. You canthen selectively replace each pel witha lighter or a darker gray, adjustingyour accumulated sum to spread outthe total number of pels per gray.

In short, you’ll do an absolutelyperfect dodge and burn.

For instance, if you have pelsin your image and use gray levels,you redefine your grays to get about

or so pels per gray level. A simpleaccumulated running average does thejob for you. Full code details in mydigital image tools on ,especially . As you cansee in figure five, nearly all of thoseavailable grays are fully and uniformlyused. Or nearly so.

Very conveniently, if you do somehistogram equalization at graylevels, it should also work with fewerquantization bits or any reduced graylevels. Thus, once you have done ahisto equalization, even reduced grayscale pictures should be dramaticallyimproved. Even more so.

By doing a histogram equalization,you can print "auto shopper" qualityimages on any unenhancedlaser printer. You’ll have the best luck with this by using a line degreescreen with grays, or else a line,

degree screen with grays.

dodgingburning

dodging paddleholds

backlighter

Arizona Highways

severely

histogram

Lena

histogram equalization

each gray gets usednearly as often as any other

GEnie

192

49152256

PSRTIMAGEKIT.PS

256

300 DPI

75 3018 70

45 19

Electronics Now

56.6

Hardware Hacker

SEMICONDUCTOR RESOURCES ( I )

955 East Arques AvenueSunnyvale, CA 94086(408) 739-1010

1180 F Miraloma WaySunnyvale, CA 94086(408) 720-8737

PO Box 3453Sunnyvale, CA 94088(800) 222-9323

70 Pembroke RoadConcord, NH 03301(603) 224-1961

2610 Orchard ParkwaySan Jose, CA 95134(408) 984-2800

PO Box 9106Norwood, MA 02062(617) 329-4700

555 Union BlvdAllentown, PA 18103(800) 372-2447

9950 Barnes Canyon RoadSan Diego, CA 92121(800) 843-3642

6730 South Tucson BlvdTucson, AZ 85706(602) 746-1111

215 TopazMilpitas, CA 95035(408) 263-3214

2231 Calle de LunaSanta Clara, CA 95054(408) 748-7700

2000 South County TrailEast Greenwich, RI 02818(401) 885-3600

1463 Centre Pointe DriveMilpitas, CA 95035(408) 945-8300

PO Box 17847Austin, TX 78760(512) 445-7222

3000 Highway 84San Gregorio, CA 94074(415) 726-3000

3901 North First StreetSan Jose, CA 95134(408) 943-2600

4401 South Beltwood PkwyDallas, TX 75244(214) 450-0400

345 Potero AvenueSunnyvale, CA 94086(408) 738-4266

1996 Tarob CourtMilpitas, CA 95035(408) 945-1323

PO Box 49007San Jose, CA 95161(408) 732-7970

2150 Commerce DriveSan Jose, CA 95131(408) 432-0500

3545 N First StreetSan Jose, CA 95134(800) 642-7616

Actel

Advanced Linear Devices

Advanced Micro Devices

Allegro /Sprague

Altera

Analog Devices

AT&T

Brooktree

Burr-Brown

California Micro Devices

Catalyst Semiconductor

Cherry Semiconductor

Cirrus Logic

Crystal Semiconductor

Cybernetic Micro Systems

Cypress Semiconductor

Dallas Semiconductor

EG&G Reticon

Elantec

Exar

Exel

Fujitsu

Figures four and five are availableas files and my

.Any time you are limited in your

gray levels, good histo equalizationbecomes absolutely essential. We sawmore details on electronic halftoningin last month’s column.

I have been meaning to do someresource sidebars that give you mostintegrated circuit manufacturers, or atleast the more hacker friendly ones.Since there’s so many of them, we’llneed several sidebars to do the jobright. So, through willappear this month, and I’ll show youthe rest of them when and as we canget to them.

Some data books are free. Othershave "optional" pricing depending onwhether the sales person likes you orwhether any of the covered chips arecurrently being promoted. For others,just about everybody has to pay thegoing rate.

Your best bet is to first request ashort form catalog, a price list, andtheir technical literature and ap noteindex. These are all usually both freeand immediately available.

Be sure to use your laser printedletterhead or a professional soundingtelephone request.

Data books for this month includethefrom . This usedto be the old opto line.

From , a on linear timers, op

amps, and comparators.From , a new data

book on .And from , a

databook. Included are lots of telco andcellular radio devices.

Our two brand new labor-of-lovenewsletters for this month do include

and the .The first is on weather satellite imagereception; the second on earthquakemonitoring and prediction.

Over in our neat mechanical stuffdepartment, a free sample of a lasermachined plastic is available from

. And an incredible catalog from. These folks are

laboring under the delusion that theyare now in the store display fixturesbusiness. In reality, they offer lots ofuseful new electronic and prototypinghardware at unbeatable prices. Not tomention off-the-wall and on-the-wallideas. They even stock Grecian urnsfor writing odes on.

For two key books on all of thefundamentals of digital integratedcircuits, try my and

, either by themselvesor as part of my

. Per my ad.As usual, we’ve gathered many of

the resources mentioned together intoeither appendix orin thesidebar. Do be sure to check these out

you use our no-charge techhelpline or calling for a free hackersecrets brochure.

Actel Fujitsu

Opelelectronic Products CatalogQuality Technologies

GE/HarrisAdvanced Linear Devices

Product Databook

Signetics/PhilipsCMOS Sequencer Solutions

Hitachi SemiconductorDevices for Communications

WeatherSat Ink Geo-Monitor

Outwater Plastics

the

CMOS Cookbook

TTL CookbookLancaster Classics

Library Synergetics

Names & NumbersSemiconductor Resources (I)

before

PSRT #463 LENA.PS#468 LENAHIST.PS

KMC

Semiconductor Chip Houses

New Tech Lit

Don Lancaster’s

Hardware HackerNovember, 1992

Distant FM receptionUFO resources listingTV/FM booster circuitsUHF & VHF amplifiersPseudoscience research

57.1

Fig. 1 – SOME POPULAR FM antennas based upon ordinary dipoles.

(A) Standard FM air dielectric test dipole.

55"

(B) "On the wall" FM twinlead Tee.

38"

(C) Seven element FM Yagi array.

Judging by the letters and myhelpline calls, there’s clearlya bunch of interest in thosealternate science and pseudo

science topics among many of you subscribers. Some

because you genuinely believe, andothers because you (as I) find thesesubjects make fascinating reading.

Your centermost two secrets to allhardware hacking are a curiosity and asense of wonder. Which explains whysuch widely ranging subjects as the

trade journal,specialty hardwoods, Grecian urns,Buckeyball research, rubber iguanas,and tinaja questing all are vastly moremainstream to hardware hacking thanthey would appear at first glance.

I come at all this from a traditionaland formal engineering background. Istrongly believe in such things as allof the laws of thermodynamics, and insimple and verifiable experiments.

I also realize that getting relevantand accurate results in the lab end upnearly always the exception, ratherthan the rule. I am a highly skepticalinquirer, albeit one who very muchloves to run a stick over the bars ofestablishment cages. And one whoalways likes to encourage people tothink things out for themselves.

As a researcher, I feel there is afuzzy something out there I’ll call

. This side of the edge, things (atleast to me) seem "probably true". Onthe far side of the edge, things appear"probably false". To determine whichside of the edge a subject currently lieson, I’ll often first apply the laws ofphysics and the ability to actuallyexperiment. Second, I’ll ask what thelaws of statistics have to tell us on theodds of an occurence and on the datasample sizes. And third, I’ll try toapply Ockham’s razor to find out ifthere is a simpler explanation or amore likely underlying cause.

After that, I’ll ask some crucialcultural questions. Such as: Where isthe cash flow? You always follow themoney. Who benefits? Who loses?What psychological or other needs arebeing filled in all those involved?

Could this make a good hoax?Were magic cookies involved? Are

there any personality disorders? Whatirrelevant links are there to religions,conspiracies, or any politics? Has thisground ever been plowed before?

Do things seem ratty? Isthere "just enough" noise, loose ends,conflict, and missing pieces to fit theway the real world actually works?Are all of the tees dotted and the eyescrossed, rather than vice versa? Are

results shown to eight decimal placeprecision conspicuously absent?

Finally, I’ll try to apply my "likeswater, looks like a duck, and quackslike a duck" filter. Especially if eggsare about to be laid…

On to today’s story. You see, I wasabducted by a enthusiast. Yup, aclose encounter of the zeroth kind.

Actually, I guess I did pay him to be

Electronics Now

Powder & Bulk Solids

theedge

slightly

UFO

Thoughts on UFO’s

57.2

Hardware Hacker

Fig. 2 – THE RHOMBIC FM ANTENNA is humongously large, but does offerexceptionally high gain over a quite a wide bandwidth.

(A) Single rhombic antenna.

to station

(B) Double rhombic antenna.

to station

Fig. 3 – MINI-CIRCUITS LABS offer a number of ultra low cost and easy to usebroadband VHF/UHF amplifiers and kits. This circuit forms an FM booster witha 20 decibel gain and a 1 decibel noise figure. Input and output impedances are50 ohms. Pre-filtering must be used to reject any strong out-of-band signals.

IN OUT

MAR-6 510

Thorough shielding andground plane construction

are an absolute must!

1000 pf 1000 pf

+12 vdc

Ω

abducted. Mike Sherlock runs a great(and one incredibly low cost) topsecret hideaway escape in the mostremote portion of New Mexico’swilderness outback. The

.Mike is a sometimes Hollywood

type who has gathered great heapingbunches of footage into what, uncut, istwelve hours of video tentatively titled

. He is now in theprocess of editing down and securingthe rights for its eventual release.

This material ranges the gamut fromprofessionally produced and largelyimpeccable network-tv footage ondown (wayyy… on down) to grainyblack and white home videos fromsouthern Florida box-only addresses.Whose special effects wouldn’t evenrate the cutting room floor of a sgrade Z sci-fi horror flick.

For once, I am at a loss for words.To call this "lore" is condescending.But calling it "evidence" seems toostrong. Besides, that word "evidence"has vastly different meanings to an

engineer, a lawyer, or a priest. So aneutral working definition: The

is the sum total of theavailable words and images on thistopic that are reasonably coherent andmore or less relevant.

After sitting through a full twelvehours of video and then some, I havecome to three tentative conclusions:

The scope, breadth, and depth ofthe resource base is now verymuch larger than I thought it was.

The potential credibility of atleast a significant subset of theresource base appears to be higherthan I thought it would.

The current resource basedoes represent a multimillion dollar

that now employs thousandson an international basis. Both in andout of government.

That appears to bethe leading industry trade magazine.Your highest profile watchdog groupis the . Your finest

directory is the new. It’s written by David

Blevins, published by , andstocked by , among others.

This is sort of a combined and . I’d give

it a four rating.Our resource sidebar for this month

shows you many of the leading placesto go for further info on ’s andany related phenomena. Both pro andcon.

As for our contest this month, justanswer the question in

words or less and send it in tome. There’ll be dozens of my usual

books, along with an all-expense-paid Thatcher, for

two going to the best of all.Be sure to send all of your entries

directly to me here at my ,rather than over toeditorial. The entry deadline will beextended for any responses arrivingfrom fifty light years or more away.Especially if they don’t have tinajas.

We have had quite a few entries inour ultra long distance receptioncontest, so I thought we might reviewwhat can and cannot be done here.

With most any problem, there areusually both technical and culturalsolutions. Judging by the absoluteoutrage hascaused locally by dropping all quality

station coverage here in the GilaValley, I do suppose such things aspetition drives, suitably annoying thepoliticians, rattling the CorporationCommission’s cage, encouraging thecompetition, or promoting translatorscould be effective.

So would changing your listeninghabits. And newer transmissionschemes are in the works with muchhigher effective ranges, especially forstereo. But, in voting with my wallet, Isimply prefer to no longer send any ofmy hard earned cash to those who Ifeel are clearly biting the hand thatfeeds them.

At any rate, broadcast stationslie in the frequency range of to

Mhz on channels spacedkHz apart. This is in a portion of theradio spectrum where thermal noise

resource base

industry

Black RangeLodge

The Marathon

Magazine

Skeptical Inquirer

Almanac ofOrganizations

PhaderaArcturcus

ThomasRegister Michelin Guide

Are we alone?

Incredible Secret Money Machine II

tinaja quest

Synergetics

Post-Newsweek Cable

1950’

UFO

(1)UFO

(2)UFO

(3) UFO

ET

UFO

70,000

(FOB AZ)

FM

FM

FM

FM88.1

107.9 200

Electronics Now

UFO

UFO

UFO

Long Distance FM

And a related contest…

57.3

November, 1992

Fig. 4 – APPROXIMATE SCHEMATIC for the Radio Shack 15-1108 TV/FMbooster antenna unit. The polarity of the dc power routed up the coax decides ifthe FM trap will be switched in or out. The low cost Motorola transistors usedhave an 8 Gigahertz bandwidth and an FM noise figure of 0.4 Decibels!

BE

EC

+-

~~

300 ohm twinleadantenna input

75 ohm dc poweredcoax from/to

base unitMRF571

T1

L1C1

L2

C3

CR1

CR3L3

C4

C5CR2

R1 R2

C6

C7

R4

R3

C12

C14

L6

CR4C13R7

C15

L5

C8

R5

C9

C10

R6

C11

C2

ultimately limits distance reception.Although daytime ignition noise canbecome dominant in urban areas.

Your reception of any nearbystations can become complicated by

and the effectswhere the signals bounce around anynearby hills and structures. Steel orwire present in buildings also can actas partial to total shielding. And anystrong nearby station that’s close infrequency to a weaker distant one canalso give you fits.

Urban solutions tend to center onsmaller directional antennas havingdeep nulls, in shielded transmissionlines that are carefully matched, and ingood receiver selectivity.

For remote rural areas, plain oldsignal strength will usually be yourmain problem. But no matter whereyou are, the higher you can get yourantenna and the nearer you can get to astraight shot at the transmitter, thebetter your resultant signal.

signals are often horizontallypolarized and best travel line of sight.In my Basin-and-Range Southwest, itis typical to have many stations comebooming in on most any mountaintopfrom hundreds of miles away. On thecheapest receivers with zilch for anantenna. But distant reception can gethairy fast if you lose line-of-sight.

Many contest entries did suggestputting an antenna on the mountainand then rebroadcasting somehow.

Perhaps as a (twounpowered back-to-back antennas thatoften works surprisingly well inspecial instances); as some

(isolated rebroadcasting onthe same frequency to preventfeedback); as a (low powerrebroadcast ing on some otherfrequency); or with an(which sends out highly directionalmodulated light pulses). Sadly, thesedon’t seem too practical for me, sinceeither going clandestine or hasslingthe Forest Service or would beinvolved. There would also belightning and power problems.

The of an antenna is simplyhow much better it works in its bestdirection than a comparableantenna that accepts signals equallywell from any direction. Raising thegain of your antenna by a mere threedecibels is the same as having thestation the transmitted power.

The standard baseline antenna iscalled a and is shown in figure

. The dipole has a figure-8 patternwhich gives it a peak gain of aroundtwo decibels above isotropic.

The dipole can be reduced in size byusing twinlead with its velocityfactor. Our figure shows you thestandard hang-it-on-the-wall indoor

Tee antenna. But don’t forget thisantenna has a "figure-8" pattern withnulls along its length, so pick yourwall accordingly.

If one dipole is good, then more ofthem should be better. A group ofdipoles form an . It turns out thatyou do not have to power all of yourdipoles. Some of them can beor elements. Usually, thefirst parasitic element will go behindyour dipole and is called a .

One or more additional parasiticelements can go in front of the dipoleand are called . Usually, thereis only a single reflector but multipledirectors. The directors are usuallyshorter than the reflector. These twoclues tell you which way to initially"point" any antenna.

Figure shows you one populararrangement for active and passiveantenna elements called a . Yagi

antennas are compact, have high gainand a stong front to back ratio.

Yagi antennas can be designed forone single station, for the entireband, or for all of and televisioncombined. Broadbanding is done bychanging the sizes, lengths, and theinterpositioning of the elements. Allother things being equal, the narrowerthe bandwidth, the higher the gain.

Ferinstance, a single channel, fiveelement Yagi might have a gain of

. That same antenna broadbandedmay have only of gain.

Thus, a single station Yagi willusually deliver a stronger signal thanwill an "all band" tv antenna.

Since they obviously would have tobe expensive special orders, you’llnormally build your own custom cutYagi antennas. One secret to narrowband and high gain is to usedirectors. I’ve posted andesign program to my .We may look at this some more in afuture column. Let me know if you areinterested.

Yes, antennas can be stacked. Butdoing so often isn’t worth the hassle.The second antenna at best adds onlythree decibels to what you’ve alreadygot. And without proper impedance

multipath picket fence

passive repeater

activerepeater

translator

optical link

gain

isotropic

double

dipole

array

passiveparasitic

reflector

directors

Yagi

very thin

GEnie

FM

FM

BLM

FM

1-A

0.71-B

FM

1-C

FMFM

11DB

5 DBFM

FMYAGI.PSPSRT

57.4

Hardware Hacker

Fig. 5 – APPROXIMATE SCHEMATIC for the Radio Shack 15-1108 TV/FMbooster base unit. Switch SW1 remotely activates the FM trap. Be careful not tomix up your cables; the dc power on the coax could cause receiver damage.

BE

EC

75 ohm outputto FM receiver

75 ohm dc poweredcoax from and to

antenna unit

MRF571

110 VAC

R1T1

C13

C14

CR1-4+

C1CR5LED

R3

R2PTC

C5 C6

SW1

C9 R6

R7 L3L2 C8

R10

C10 J2

C11 R11 R9 C12

R8

C7

C15

R4

R5

C4

L1

C2 C3

J1

matching, you can actuallyyour signal.

The is a lowcost Yagi-like antenna having threeactive elements, three directors, and areflector in a reasonably compactdesign. This can be a good choice forall but the deepest of fringe areas. Butit looks to me like they cheated a tadon the overall size.

While Yagi-style antennas areoften the simplest and best, there isanother Hacker alternative. This onegets called a antenna, and isjust a parallelogram of wire sent eitheraround or across your room. Figuretwo shows details.

Intuitively, a rhombic has a muchlarger area and thus (when properlydesigned, properly aligned, and usedin a proper location) intercepts moresignal for a potentially higher gain.

Large (70 foot) outdoor doublerhombics can reach a mind-numbing

decibels of gain! Broadband, yet.But there is so much that can go

wrong with a rhombic design and somuch cut and try is involved, that youmay want to save this as a last resort.And then only when there are no

strong local stations.One useful paper on these rhombic

antennas is run in the March

. You also might want tocheck inthe issue of .

More info on Yagis, rhombics, andantennas in general can be found inany of a number of college or hamtexts. The s ortheby Jasik are typical classics.

Reception of signals can end upmore art than science. So, if you areonly interested in one particularstation and all else fails, try blackmagic. Change the antenna directionand position to try and find a local hotspot. You might try extra pieces ofconductor in or near your antenna. Inone trial, I found that shorting theantenna cross feed with an aluminumyardstick dramatically improved theresults for one target station.

Some stations add a vertical or acircular polarization to their pattern toimprove their mobile reception. So, anon-horizontal antenna sometimesmay work better than you would first

expect. Try it and see. Should you bemainly interested in one station, callthem and ask what pattern they use.

One final trick to deal with a noisy signal is to reduce its bandwidth.

The quickest and simplest way to dothis is to switch from stereo to mono.This halves your bandwidth and thusreduces your noise by three decibels.Some advanced car radio circuits dothis automatically.

It is also possible to use low passfilters (such as the treble control ormessing with your loudness curve) tofurther reduce your received noise.While, of course, losing the station’shigh frequencies as well.

We better throw in some obvioussafety warnings here: Outside and/orhigh antennas must receive lightningprotection. Antennas can kill you ifyou hit a power line when installingone. And any ladders and heights ingeneral could cause deadly falls.

Will an "booster" amplifier helpus at all? Can’t we simply make thereceived signal louder?

For a number of reasons, boosteramplifiers can be a disappointment toan outright disaster. But, with somecare, boosters do have their uses.

For any chosen station, any givenreceiving antenna at any given placepointing in any given direction, therewill be so many microvolts of signalappearing at your antenna terminals.There’ll also be so many microvolts of

that appearsacross the antenna terminals. Atand higher frequencies, the amount ofthis rural noise usually gets set by the

of the antenna, and littleelse. At least for a given bandwidth.

The ratio of these two voltages isknown as the . A

ratio that can produce oflimiter is needed to give you"good" reception. Anything lessgets progressively noisier.

For a given fixed bandwidth andreception scheme,

All the booster amplifier can do isamplify the signal the noisetogether. Thus, if your input signal tonoise ratio is too low, there isthat amplifier can help you.

degrade

Radio Shack

rhombic

Improved Antennas of theRhombic ClassRCA Review

Try a Rhombic FM AntennaJanuary Audio

Antenna BookAntenna Engineering Handbook

thermal agitation noise

temperature

signal to noise ratio

quieting

there is no knownamplifier or other electronic methodto improve the input signal to noiseratio across your antenna terminals!

both and

no wayany

15-1636

$17

FM

FM

28

1960

1982

ARRL’

FM

FM

FM

FM

FM

FM

S/N 20 DB

FM

FM Booster Amplifiers

November, 1992

57.5

UFO RESOURCES

PO Box 831383Stone Mtn, GA 30083(404) 297-4624

Star Rt. 2, Box 119Kingston, NM 88042(505) 895-5652

PO Box 429Garberville, CA 95542(707) 986-7211

Box 399Careywood, ID 83809(208) 683-2439

PO Box 25962Munds Park, AZ 86017(602) 955-8034

PO Box 5636Security, CO 80931(719) 475-0918

PO Box 538Bradley, IL 60915(815) 935-5353

103 Oldtowne RoadSeguin, TX 78155(512) 379-9216

PO Box 172Wheat Ridge, CO 80034(303) 431-8796

PO Box 1241San Bruno, CA 94066(415) 359-0432

PO Box 81Rosholt, WI 54473(715) 344-5585

PO Box 703Buffalo, NY 14226(716) 636-1425

PO Box 2246Rockville, MD 20847(301) 881-3530

PO Box 342-MYucaipa, CA 92399(714) 795-3361

PO Box 1053Florence, AZ 85232(602) 868-4273

PO Box 1053Sunland, CA 91041(818) 769-2917

PO Box 1053Sunland, CA 91041(818) 951-1250

Rt. 1 Box 220Plumerville, AR 72127(501) 354-2558

Arcturcus Books

Black Range Lodge

Borderland Sciences

Eden Press

Genesis Publishing

High Energy Ent.

Lindsay Publications

Mutual UFO Network

ParaNet Info Service

Phaedra Enterprises

Search Magazine

Skeptical Inquirer

Strange Magazine

UFO Audio/Video

UFO Books

UFO Database

UFO Magazine

UFO News Service

Put another way, you just cannotamplify a signal that is not there.

Further, any booster amplifier willadd its noise and alwaysyour signal to noise ratio. The extraamplifier noise over and above thethermal background is known as the

. With care and using thelatest of transistors, an firststage noise figure under half a decibel(around five percent amplitude) caneasily get done. On the other hand,throw in any old el-cheapo transistor,and your noise figure can easilyget outrageously bad.

Worse yet, if there are any strongsignals that are also being amplified,these can overload your booster amp,splattering themselves all across theband and creating . It’s real easyto convince yourself that your boosteramp gave you "lots" of new stations;in reality it is just the crossmod fromstrong local signals.

Finally, quite a bit of design efforthas gone into the front end of mostpremium receivers. Unless yourbooster has a design than your

receiver, it is almost certain todegrade, rather than improve yourreception. Most of those el-cheapobargain boosters found in the yuppycatalogs will often make your signals

, rather than less noisy.So, what good is a booster? A high

quality and properly designed boostercan make up for transmission lossesdown long cables. They can present amore standard and a better matchedload for your antenna. They can makeup for a cheaper receiver front enddesign. Or for standing waves andsome impedance unbalances. And theyare particularly useful when you wantto drive two or more receivers fromone antenna at the same time.

Figure 3 can show you a simplebroadband hacker amplifier youmight like to experiment with. Thisuses a low cost integrated amplifierfrom . Since this isa very wideband circuit, you do haveto watch for saturation effects fromany interfering signals. And thoroughshielding is a must. Naturally, addingresonant circuits and limiting yourbandwidth can give you betterresults for the frequencies you areinterested in. But that sure makes thedesign a lot more complicated.

has a newer

broadband booster that uses apair of exceptionally hot new

transistors. doThese have an eight Gigahertz cutofffrequency and an band noisef igure of only decibels !Approximate schematics for theantenna and base units are shown youin figures four and five.

The antenna unit is made up from aswitchable trap (just what we do

need!) and one fairly low gainamplification stage and cable driver.The twinlead serves two purposes: Itroutes power up from their basestation and downlinks your partiallyamplified signals. The polarity ofthe power decides whether thetrap gets switched in or out. Ordinarysilicon diodes do the switching.

You might like to experiment withcompletely eliminating the trap. Idon’t trust its being there at all, evenin its supposedly "off" position. To dothis, you could try removing , ,

, and , while replacing withthe shortest possible jumper.

The base station is made up of apower supply and another transistorwhich acts as a line driver or as adistribution amplifier. There’s also anadjustable attenuator to optimize thesignal levels.

has announced severalreally exciting new chips. Especiallythe new single chip

and their new.

We do have a collection of unusualpublications this month. Tony Pattistill prints histhat’s big on cryptography and chaostopics. And the

is a great labor-of-lovenewsletter by Chris Crawford.

Two unique music newsletters are and

. And newlyoffers several "Holistic Approaches toTechnology and Environment."

The folks atare offering a number of new titles.These include a turn-of-the-centuryreprint on , anda new one on do-it-yourself

.I’ve been self-publishing quite a

few titles these days using my new process. Included

are my reprints II &III, my reprints I, II, &III; my , the new

, and my book and disk combo.

own lower

noise figure

spurs

better

more

Mini-Circuits Labs

much

Radio Shack

Motorola

not

Motorola

ClosedCaption TV Decoder

Digital Audio Transceiver

Cryptosystems Journal

Journal of ComputerGame Design

Experimental Musical InstrumentsGuitar Digest Solar Mind


Large Induction CoilsLightning

Bolt Generators

Book-on-demandHardware HackerAsk the GuruBlatant Opportunist

Resource Bin I LaserWriterSecrets

UHF FM

FM

FM

FM

VHF

15-1108

TV/FM

MRF571

FM0.4

FM

DC

RFDC FM

FM

L1 L2R2 CR2 L3

MC144143

DSP56401

I

New Tech Lit

Hardware Hacker

57.6

December, 1992

Don Lancaster’s

Hardware HackerConventional currentsAssorted wondermentsFM Yagi antenna designNavigation & NavicubesTwo new piezo rate gyros

58.1

Fig. 1 – THE CONVENTIONAL ELECTRIC CURRENT goes from negative topositive in any energy source and from positive to negative in any energy sink.This is THE standard used by all graduate engineers, physicists, electronicsymbols, and industry worldwide. It even appears on the IEEE cufflinks.

The conventionalcurrent travels from

toin any .

NEGATIVE POSITIVESOURCE

The conventionalcurrent travels from

toin any .

POSITIVE NEGATIVELOAD

+

So many exciting new hackeropportunities have come downthis month that I do not evenknow where to start. We seem

to be moving into a boundless newera of hardware hacking.

Before we begin, though, there’vebeen a few recent helpline calls oversome really ancient history which weshould go over one final time…

Which way does the current travelin any electrical or electronic circuit?Many years ago, one of the electricalpioneers ventured his wild that

.It took over a century to verify, but

the guess turned out to be correct. Atleast for certain solid state circuits atleast some of the time.

To this day, this guess is called the electrical current, and

appears in figure one. Conventionalcurrent is the standard taught in

university and graduate levelengineering courses, gets used byphysicists, and accepted by largeelectronic firms worldwide.

Conventional current is shown inthe direction of the arrows on thestandard electronic symbols. Even the

tie clasp and cuff links stronglyrestate the conventional current. Sodoes the righthand generator rule andlefthand motor rule.

Yeahbut, just which way does thecurrent go? Well, a glib answerfor the new age nineties is "any wayyou want it to".

In semiconductor loads, the currentdirection gets decided by the majoritycarriers. In any transistor or anyP-channel , conduction is byhole carriers, and the current does infact go in exactly the same directionas the conventional current. In N-typedevices, the current is the opposite ofthe conventional current direction.

So what is the problem? And whyam I standing here whipping this longdead horse?

Way on back during World War , vacuum tubes were very few and

far between. Come to think of it, theystill are. Because of this, the militaryintroduced the concept of the

to explain how a vacuum tubeworks. And many trade schools andlower level textbooks continued thispractice into the fifties and sixties.

Which led to the absurd result thata few hackers, technicians, and muchof the hobby press had their currentsheading in one way, while all of theengineers, physicists, and the rest ofindustry had their currents heading inthe exact opposite direction.

The bottom line: If any individualor any textbook still tries to teach youelectron current, they are ripping youoff. They are also doing you a seriousdisservice that will lead you to untoldconfusion and latter day hassles.

electron nor conventionalcurrent is correct all of the time. Theoverwhelming majority of industryand professional level traininggoes with the conventional current.

Among the other reasons, becausethere is no compelling reason not to.

Just what would it take to convertindustry over to electron current? Foropeners, extremely frigid conditionsin a distinctly unpleasant locale. Or

some words to that effect. Even then,I would not expect to see this happenuntil a few weeks after the Ayatolla’sBar Mitzvah.

When in Rome, go with the flow.Or too many cooks gather no moss.Er, something like that there.

Way on back in, we looked at the , a

inch and a dollar cube that alwaysknew where it was and which way itwas pointed. Well, we still don’t have

Navicubes, although I do expectsome Korean toy manufacturer or twokids in an Iowa basement to shortlycome up with a really good one.

A lot is happening with Navicubes,both evolutionary and revolutionary.An update summary of Navicube infoappears as our resource sidebar.

Today’s popular approaches to theNavicubes include the satellitesystem, fluxgates, real gyros, lasergyros, accelerometers, and a pair ofbrand new piezo gyros.

The global positioning systemis going great guns. Their eighteenthsatellite is now in orbit, and Russianand competing systems are nowbeing established. Receiver prices arein free fall, and the barrier has

guesselectrical current always goes fromthe negative to the positive terminalin an energy source and from positiveto negative in an energy sink

conventional

onlyall all

allall

all

really

electroncurrent

Neither

always

Hardware Hacker#7 Navicube

IEEE

PNPMOSFET

IIPNP

310

$10

GPS

GPS

ECC

$500

Follow that current!

Navicube Update

58.2

Hardware Hacker

Fig. 2 – NEW DEVELOPMENTS IN PIEZO RATE GYROS should eventuallylead to low cost Navicube solutions. A rate gyro tells you how fast you arenow turning. Integrating the turn rate (summing through time) gives you thecurrent direction.

(A) The Systron-Donner GyroChip is based on two coupledtuning forks. The Coriolis force from any rotation aroundthe vertical axis changes the phase and amplitude of thesynchronously demodulated output signal.

DRIVER

SENSOR

(side view)

(B) The Murata-Erie GyroStar is based on carefully controlledvibration modes in a triangular piezo element. Any relativeclockwise or counterclockwise rotation changes the phaseand amplitude of the output signals.

DRIVER

LEFTOUTPUT

RIGHTOUTPUT

(top view)

recently been broken. is your foremost trade

journal. They’ve also just started up anew shopper.As before, the

is the finest Navicubetechnical resource.

Although is still the mostobvious source for the chipsets,

has just developed anew single chip front end. Whiletoo early for a part number, severaldetails now appear in

for August . I expect cheapnew parts real soon now, fromseveral obvious sources.

North sensors are best done usingfluxgate magnetometers. Radio Shackhas a cheap one in their car compass,

and sells expensive commercialunits. We have seen several fluxgateconstruction projects and referencesin those reprints.Naturally, any magnetic sensor getsconfused by nearby iron.

Many hackers still labor under thedelusion that Hall Effect devices canbe used as compasses. Well, possiblythey can, but fluxgates areof times more sensitive.

One exception is the very low cost magnetic compass sensor.

Sadly, its best possible accuracy is acrude degrees.

Solid state accelerometers continueto drop in price, spurred on by newerautomotive uses, especially airbags.While and are

the largest suppliers, the better pricedand more innovative sensors are nowprovided by , ,

, and .Your two best accelerometer trade

journals areand .

Note that you could integrate (sumthrough time) any acceleration to getvelocity, and then integrate velocityto get the position. There is one hugetechnical hassle with accelerometers,though. This is called the "t-squared"problem. Any bias or similar error inacceleration ultimately piles up as aposition error that is proportional totime .

Which means if you wait aroundlong enough for your position, it iscertain to be wrong. Accelerometerswork best for short term uses, whenthey can be repeatedly recalibrated orreset from some other standard everynow or then.

Your classic nav usually got doneby using mechanical gyros. These arenothing but rapidly spinning masses,comparable to a toy gyroscope. Thesecan be costly, cumbersome, and ofteninvolve precision elements rotating atvery high speeds. Gyros are availablesurplus from ,

, and. One current manufacturer is

.Yes, there are laser gyroscopes. A

coil of fiber optic cable has coherentlaser light beams routed through it inopposite directions which then can bephase compared. But not much seemsto be happening here to drop the costsby the needed to make them apractical hacker tool. Good info onlaser gyroscopes is available from the

and from .But our really big Navicube gyro

news for this month involves a pair ofbrand new…

A is a special gyroscopewhich can tell you how fast you are

. By integrating your rate ofturn, you can get your direction. Bycombining this with some separatelymeasured velocity, you can find yourcurrent position. And there will be not-squared problem, since no doubleintegration is involved.

Traditional rate gyros are available

GPS World

GPS World ShowcaseJournal of the Institute

of Navigation

Rockwell

Hewlett Packard

Microwaves &RF

KVH

Hardware Hacker II

thousands

Dinsmore

Motorola Micro Switch

Analog Devices SenSymIC Sensors NovaSensor

Measurement & ControlSensors

squared

Fair Radio Sales RadioResearch Instruments AST ServoSystemsHumphrey Products

IEEE Press SPIE

rate gyro

turning

GPS

GPS

1992GPS 22.5

1000:1

Solid-state rategyro breakthroughs

58.3

December, 1992

Fig. 3 – WAVELET TUTORIALS AND SHAREWARE available on GEniePSRT. You can call (800) 638-9636 for your voice connect info.

Reprint of from . Wavelets update includesoptical applications, and new book.

Reprint of from . Wavelets are oneof the eight hacker-friendly emerging tech opportunities reviewed.

Reprint of from the .Brief summary on wavelets and a key resource bibliography.

Utility to unPAK an IBM ".PAK" file, such as #365 WAVELET.PAK

Reprint of from . Wavelets update,including new book, IEEE-SP tutorial, Aware application notes.

Reprint of from . Mentions book and software from .

Complete and ready-to-run IBM Wavelet Packet Lab shareware. This is a .PAKcompressed file that needs file #403 or its equivalent for unpacking.

Reprint of that discusses three video compression schemes.These include wavelets, DCT/JPEG, and fractal compression methods.

Reprint of from . Fundamentals oftransforms, along with examples of wavelet video compression.

Reprint of from . A first introduction towavelets and wavelet theory. Includes 13 entry sampler bibliography that showsthe wide extent of wavelet aps.

#508 HACK58.TXT & #509 HACKFG58.PS

#494 EMERGOP2.PS

#456 WAVELETS.PS

#403 PAK251.EXE



#365 WAVELET.PAK

#313 GURU73.TXT & #314 GURUFG73.GPS


#195 HACK38.TXT & #197 HACKFG38.GPS

Hardware Hacker #58 Electronics NowTen Lectures on Wavelets

Blatant Opportunist #17 Midnight Engineering

The Wavelet Onslaught Midnight Engineering Companion #2

Hardware Hacker #50 Radio-Electronics

Hardware Hacker #49 Radio-Electronics Wavelets andtheir Applications Ultrawave Explorer Aware

Ask the Guru #73



from the sources of regular gyros wejust looked at. A hackable and a lowcost fluidic rate gyro was done a fewyears back by Doug Garner at ,which used an airstream differentialcooling a pair of thermistors. But nottoo much seems to have come of thisapproach either.

A pair of new "solid state" rategyros are now available. At least oneof these promises to end up as acomponent. Because these both usevibrating piezo structures, it is notquite correct to say that they have nomoving parts. But these certainly aresimple and rugged single piece unitswhich involve zero rotating parts orprecision mechanisms.

The first unit is the by and shown in figure

. This is a pair of back-to-backtuning forks machined from a singlepiece of silicon. The phase of youroutput signal gets determined by the

force caused by turning.The seond piezo gyro is that new

by , and shownin figure . This is just a triangularpiezo oscillator. The Coriolis force ofrotation again changes the phase ofthe output signal in proportion to therotation rate. This new scheme looksridiculously simpler and vastly moreelegant than the GyroChip design.

While both of these breakthroughdevices have the potential to becomelow cost parts, the sample costs todayare for Murata’s GyroStar, anda ludicrous for the GyroChip.Their support literature so far is alsoutterly dismal. But a new HongKong ripoff is just about certain toquickly become available.

Continuing this month’s stunningnew developments, here is a doublehandful of great new stuff…

Be sure to check out

in the August issueof . What we haveapparently got here is a unique newconcept and toolset for video, movie,and multimedia editing.

Put one frame of a small image inthe upper left of your monitor screen.Next, move on down one pixel andone pixel to the right, and then repeatthe process for the next frame in your

sequence. Continue until you have adiagonal smirp on down your screen,ending with a final full small image.While you are at it, show your soundamplitude for each frame along thetop diagonal of the smirp.

What do you have? In one placeand at one time, a display which letsyou view the of a

of multimedia or othervideo. In short, you can instantly look

,seeing the relationship between yourcurrent frame, its recent history, andits near future!

Looking at this "striking" conceptslightly different, say you had a fewfeet of movie film. Cut the individualimages apart so they have no borders.Stack them up and look attheir top and left edges. Once again,in one place and at one time, you cansee what has happened and what isgoing to happen. An instant and realtime plot of images versus time.

Naturally, the edges will only showyou wildly abstract colors or patterns.But, with practice, those patterns caneasily be read as to the scene, cameraangle, panning, duration, sound sync,and much more.

A non-obvious ap: Quickly findinga buried sequence in a humongousvideo data base. It is sort of the videoequivalent to that , or

long usedin data bases.

The editing, tweening, scanning,high speed access, and all the visualflow possibilities of this new schemeseem boundless.

The onslaught continues.A second book is now available andtitled byIngrid Daubechies and published by

, shorthand for the.

While a first rate text, this is a veryadvanced math book that makes for

NASA

GyroChipSystron Donner

Coriolis

Gyrostar Murata-Erie

Image Striking–Motion Imaging Processing: StrikingPossibilities

Advanced Imaging

temporal contenttime sequence

forward or backward through time

sideways

indexedsequential access method

Wavelets–

Ten Lectures on Wavelets

SIAM Society forIndustrial and Applied Mathematics

$5

2-A

2-B

$300$2000

$5

1992

ISAM

Assorted wonderments

58.4

Hardware Hacker

Fig. 4 – FOLDING A DIPOLE raises its resonant impedance by four times.

(A) An ordinary dipole has an impedance of a balanced 75ohms resistive just below its resonance. But any thickconductors or nearby elements lower this resistance oradd some unwanted series reactance.

0.48

(B) Folding a dipole into a hairpin loop will raise its inputimpedance by four times. The impedance just belowhalf of a wavelength is a balanced 300 ohms resistive.Careful tuning is needed in the real world.

λ

0.48λ

rough reading by mere mortals.A brief story on optical wavelet

uses appears in the August issue of . All those opticsfolks sure do have it easy. They justdump a pile of crockery on the table,squirt some light through it, and theyget instant real time 2-dimensional

or wavelet transforms. Noneof the old point-by-point computationnonsense for them.

An entire issue on optical wavelettransforms appears as the September

issue of . Ihave added and

toto go along with all the rest of ourwavelet downloads. A complete listappears in figure three.

I amstill looking for a hacker solution thatmakes printed circuit plate-throughholes cheaply possible at home. Orsome workaround which flat out doesaway with the need for plate-thru.

A major step in this direction hasbeen taken by . Whose new

special adhesive lets you build ultraexpensive multilayer boards out ofthe cheaper double sided ones. Sadly,you still need some plate-through.

Their is basically a newadhesive which conducts only in itsthickness direction. Just take a pair ofdouble sided boards and selectivelyapply this adhesive to one of them.You then add heat and pressure tobond the pair together. You can endup with either a three layer or a fourlayer board at a tiny fraction of thegoing price. And, yes, you can do sixlayer, eight layer, as many as youwant. Even have buried plate throughholes! Far simpler, cheaper, and witha much lower scrap rate than before.

Carefully isolated solder particlesmake the adhesive conduct in onlyone direction. Their conductivity isabout the same as real multilayer.

A small free sample is availablefrom Sheldahl on request.

The price of Buckyballscontinues to drop dramatically, andthese are now hacker affordable. The

leading supplier remainsand their pricing starts as low asa gram raw, and per gram fullyrefined. Minimum order is .

Meanwhile, a carbon formhas been discovered that is called the

. Hollow cylindrical pipesof carbon that have both the hardnessof diamond and the surface area ofgraphite. Possible new uses includelubricants, and unique materials thatconduct heavily in only one direction.Check out the August issue of

for a summary update.

Last month, we checked into thefundamentals of distant reception.We have had some requests for stillmore info, so here goes…

The noise situation at Mhz is atad further complicated than I firstmade out. If you do have any remoterural site, then your first stagethermal agitation noise does in factdominate. And the best noise figureyou can get is super important.

Atmospheric noise is negligible at frequencies. Galactic noise runs

ten decibels or so above around MHz. But you do not normally

point a antenna straight up on aclear day, so this is also no problem.The potential killer is the man-madenoise, which can be decibels above

in suburban locations, anddecibels or more in urban locations.Nearby dimmers or computers couldalso induce these noise levels.

Most of the man-made noise comesfrom car ignitions. It sure would beinteresting to watch the try andenforce the same Part rules andregulations on Detroit iron that theydo on Hardware Hackers. Talk aboutpotential noise levels! The howl overthis would be unbearable.

At any rate, you’ll still want to getthe best first stage noise figure youcan. But it might not help you out toomuch if your external noise is muchstronger than .

On the other hand, a slight increasein antenna gain can make a dramaticimprovement in your reception.

This happens because of a limiter’s. For instance, if you’ve

got a noisy signal, an increase ofonly decibels in antenna gain or

ratio can make up to a or decibel improvement in receiver

Photonics Spectra

Fourier

Optical Engineering

GEnie

Multilayer PC Breakthrough–

Sheldahl

Zlink

Buckyballs–

MER Inc.

fourth

Buckytube

E.E.Times

capture effect

twoseven

eight

1992

1992#494 EMERGOP2.PS

#456 WAVELETS.PS PSRT

$5.50$90

$50

17

FM

100

KTB

FMKTB

100FM

25KTB 40

FCC15

KTB

FM

FM

S/N

1900

More on FM antennas

58.5

December, 1992

Fig. 5 – AN INDOOR SINGLE-STATION long distance FM antenna can bebuilt using nothing but bare #12 house wire. Here is one possible design.Note that the antenna size should be "cut" for your favorite station. Valuesshown assume an insulated boom or other supports. All elements must bevery straight, rigid, parallel, and precisely centered.

All dimensions are shown in decimal inches. Theantenna is shown top view, and assumes the station ishorizontally polarized.

To cut your antenna for a specific station, divide thestation frequency by 100 and then divide all sizesshown below by the same value.

For instance, a 93.3 Mhz station needs all the valuesdivided by 0.933. A 104.5 Mhz station needs all of thevalues divided by 1.045.

5 9. 5

6 "

5 5. 5

3 "

5 3. 7

6 "

5 3. 0

2 "

5 3. 0

2 "

5 3. 7

6 "

23.52" 29.52" 29.52" 29.52" 29.52"

MATCHINGDEVICE

quieting.I’ve found several interesting

antennas. The Radio Shack ischeap at and easy to find. And itdoes a good job in near fringe areas.But it is just plain too small. It onlymeasures four feet by five feet, whilea no-compromise Yagi solution willmeasure five by thirteen.

Radio Shack used the broadbandco-linear array, rather than a Yagidesign. Then, to save on the materialsand size, they apparently designed itup at Megahertz or so and hopedsome gain remained down in theband. Almost always, a broadbandantenna has lower gain than one cutfor a single station. From their pointof view, this is a useful engineeringmix that gives you a small and cheapsolution which meets the needs of amajority of their customers.

Their gain is over a dipole.Your most rugged "real"

antenna is the . Thisis available by way of , theleading cable distributor chain.The gain is decibels over a dipoleand the cost is around . Size isby inches.

Another interesting antenna is the with a decibel

gain in a inch boom length. Theprice seems high at .

The highest gain stock antenna Ihave found is the ,that has a whopping decibels ofgain on a inch boom and costingaround . This appears to be thebest choice.

Be sure to remember that raisingyour antenna height is usually yoursurest way to improve your signal tonoise ratio in typical locations. Thecloser to line of sight you can get, thebetter the results.

But I live in a pecan grove. Nuts.My trees glop over everything, mostespecially antennas. So some indoorsolution seemed better for me.

What about building your ownsingle station antenna? In theory,you could pick up another decibel ortwo of and as much as ofquieting over full band commercialdesigns. Especially if you are extracareful in tuning and matching. Andif you have a high loft in your livingroom or a wire- and metal-free atticcrawl space, an indoor design can bemuch cheaper than a mast mounted

outdoor one. With fewer hassles. Anda Yagi is just a bunch of free floatingconductors sitting in magic positions;a wood frame and grommeted screweyes can be used for support.

First, note that there are two stylesof driver elements to a Yagi antenna.As figure four shows us, if you use ahalf wavelength hairpin loop,your terminal impedance should endup near a balanced ohms.

If you use a pair of straight wiresof half wavelength total spacing, thenyour terminal impedance should be abalanced ohms. Note that normal

Ohm coax is unbalanced; you willneed a baulin or a transformer toget from balanced to unbalanced.

Note that driver impedances insidean antenna array usually end upthan these values. They also must becarefully matched for best results.

The bottom line: use a hairpin loopfor ohms balanced or the pair ofquarter wave wires when you wantohms balanced. Either way, a final

matching will still be needed.A six element narrowband Yagi cut

for Megahertz is shown you infigure five. Use quite but rigidconductors for your best narrowbandgain. Something like solidcopper house wire might be a goodchoice. To cut this antenna to yourdesired station, the frequencyin Megahertz by and thenall sizes by the resultant number. Forinstance, to pick up at , allelement lengths and all spacings willget divided by . Note the inverserelationship: stations Mhzneed slightly antenna designs.

The directors should point towardsyour chosen station. Use a map forstarters, and then try rotating a tadeither way. Your beamwidth shouldbe around thirty degrees, so pointingjust right is super important.

Additional directors can in theorybe added, in a size progression. Butyou only gain something like half adecibel per director, and the size does

CushcraftAnixter

ChannelMaster

Winegard

dipole

lower

thin

bare

dividedivide

underlarger

FM15-1636

$17

120FM

6.4 DBFM DX

Y-FM5

TV9.5

$70 59104

4408 9138

$104

CA-606510.6

127$78

FM

S/N 8-10 DB

300

7575

1:1

30075

100

#12

100

KDKB 93.3

0.933100

58.6

Hardware Hacker

NAVICUBE RESOURCES

PO Box 9106Norwood, MA 02062(617) 329-4700

115 Main Road, Box 97Montville, NJ 07045(201) 335-1007

6120 Hanging Moss RoadOrlando, FL 32807(407) 678-6900

1814 Remell StreetFlint, MI 48503(313) 744-1330

PO Box 1105Lima, OH 45802(419) 227-6573

PO Box 10460Eugene, OR 97440(503) 343-1200

PO Box 10301Palo Alto, CA 94303(415) 857-1501

9212 Balboa AvenueSan Diego, CA 92123(619) 565-6631

1701 McCarthy BlvdMilpitas, CA 95035(408) 432-1800

445 Hoes LanePiscataway, NJ 08855(908) 981-0060

1800 Diagonal St Ste 480Alexandria, VA 22314(703) 683-7101

110 Enterprise CenterMiddletown, RI 02840(401) 847-3327

2994 W Liberty AvenuePittsburgh, PA 15216(412) 343-9666

11 W Spring StreetFreeport, IL 61032(815) 235-6600

611 Rt #46 WestHasbrouck Heights, NJ 07604(201) 393-6286

2200 Lake Park DriveSmyrna, GA 30080(800) 831-9172

41 E 42nd Street Ste 921New York, NY 10017(212) 490-3999

1055 Mission CourtFremont, CA 94539(415) 490-9100

584 North Main StreetWaterbury, CT 06704(203) 753-5840

PO Box 568842Dallas, TX 75356(214) 996-5863

174 Concord StreetPeterborough, NH 03458(603) 924-9631

1255 Reamwood AvenueSunnyvale, CA 94089(408) 744-1500

PO Box 10Bellingham, WA 98227(206) 676-3290

2700 Systron DriveConcord, CA 94518(800) 227-1625

Analog Devices

AST Servo

FW Bell

Dinsmore Instruments

Fair Radio

GPS World

Hewlett-Packard

Humphrey

IC Sensors

IEEE Press

Journal of Navigation

KVH Instruments

M&C

MicroSwitch

Microwaves & RF

Murata

NASA Tech Briefs

Nova Sensor

Radio Research Instruments

Rockwell

Sensors

SenSym

SPIE

Systron Donner

get out of hand real quick like. And acareful match, or finding a local hotspot, or a tad extra height can oftenget you much more signal.

The theory behind a Yagi antenna?The optimum spacing is usuallywavelengths. Your driver should behalf a wavelength wide. The reflectorshould be around five percent longer,while your initial director should befive percent shorter. The rest of your

directors should progressively be six,seven, eight… percent shorter.

More on Yagi antennas appears intwo publications, the

and .Also see technical note .

Close matching of an antenna to itstransmission line is essential for thebest gain. Your simplest method iscalled a match, and gets doneby just spreading the ends of a

ohm twinlead to tap maximum signalstrength. Better methods appear inthe above books.

It would be real interesting to routeboth of your dipole rods straight intoa differential amplifier. Such an

can greatly simplify yourtuning and matching.

But a lot of black magic could beinvolved, so be sure to experiment.

Let me know all your experienceswith any homemade ultra rangeantenna designs. I’ll try to publish thebest of them.

A greenfrom . This little knownsemiconductor house offers all sortsof exciting hacker chips. Especiallythose involved with tone signalling,speech scrambling, cellular phones,and pagers. One real sleeper: Their

octal digital gain controlledamplifier array. Lots of ap-notes arealso included.

Free engineering samples of theirnew humidity sensor havebeen offered on professional requestfrom .

is yet anotherDistressed Yuppy Surplus direct mailoutfit. They have all varieties of hightech goodies. Their latest new catalogdoes offer the first laser pointers thatI have seen for under .

and are the twoleading trade journals for the coinoperated video game industry. Whilethese mostly center on the buying andselling of games and supply products,there are occasional technical articlesplus repair books and videos.

If you are interested in starting upyour own tech venture, be certain tocheck into my at long last available

.We are also newly shipping the latest

reprints withtheir newest updates. See my nearby

ad for more details.A reminder here that lots of great

technical downloads are available on.

As usual, we’ve gathered many ofthe resources mentioned together intoeither of the or the

sidebars. Do besure to check these out you useour no-charge tech helpline or call fora free hacker secrets brochure.

AntennaHandbook Yagi Antenna Design

gamma

antennafier

1991 Product HandbookMX-Comm

Victory EngineeringHeartland America

RePlay Play Meter


Hardware Hacker III

Synergetics

GEnie

Names & NumbersNavicube Resources

before

0.2

ARRL

NBS #688

300

VHF

FM

MX009

41VHS-1

$100

PSRT

New tech lit

Don Lancaster’s

Hardware HackerJanuary, 1993

High side FET driversDrawing semilog plotsLaser printer repair kitsResonance fundamentalsFar East electronic sources

59.1

Fig. 1 – A RLC SERIES RESONANT CIRCUIT forms the basis for variouselectronic tuning, filtering, voltage step up, and energy storage circuits. Butthere is no way I know that it can produce any "free" energy.

~C L

R

The occurs whenever both theinductive and capacitive reactances are equal…

RESONANCE FREQUENCY

f =______1

2 LCπo

AMPLITIUDE RESPONSEThe defines the ratio of the inputto the output voltage, expressed in decibels…

=____e

e –20 Log 1 + Q _____f - f

f

out

in 102

2o

2

The or is defined in several differentways, each of which leads to a different application…

Q QUALITY FACTOR

(A) As the reactance to resistance ratio…

Q = ______2 f L

R

π o

(B) As the half power bandwidth…

Q = _____f

f - f

o

h l

(C) As the inverse of the damping…

Q = ___1d

(D) As the resonant voltage rise…

Q = ___________________________(resonant voltage across L or C)

(resonant voltage across R)

(E) As the ringing rundown time…

A resonant circuit decays to 1 / amplitude(or 37% = -8.7 decibels) in Q / cycles.

επ

(F) As the stored energy ratio…

Q = ________________________2 (energy stored per cycle)

(energy dissipated per cycle)

π

Afew additional comments onthe correlation from back inHardware Hacker #54. Ourthird autocorrelation mask

example obviously should have beenan 0010 rather than the typo shown.I’ve corrected this in our HardwareHacker IV reprints.

I should have stated "Radar rangedepends upon your transmitted pulseenergy, rather than is proportional to.Doubling the transmitted radar pulseenergy typically can only extend youreffective range by nineteen percent.

Good classic texts on radar includeMerrill Skolnick’s Radar Handbook,and the hoary old "Rad Lab One" thatrefuses to die. Otherwise known asRadar Systems Engineering by LouisRidenour. Another very outdated butpopular intro is Robert Page’s Originof Radar from Doubleday.

While much of the information onchirp radar techniques is classified orotherwise hard to locate, the Theoryand Design of Chirp Radars in theBell System Technical Journal forJuly of 1960 is a good intro. I’ve alsogot a summary in my January 1965Electronics World chirp story. Morecurrent info can be found through theDialog Information Service.

Numerous readers have questionedthat unusual synchronous rectiferexample circuit. Yes, this is correctas shown. And, yes, there is one bighidden gotcha. When a MOS powertransistor gets used for a synchronousrectifier, you will run it in its thirdquadrant. Not the first quadrant likeyou might initially expect. This getsdone to keep the substrate diode fromshorting out the works.

More on quadrants below.Additional details on synchronous

rectifiers do appear in that MosPowerApplications Handbook by Siliconixand in those Motion, Motion Control,PCIM, or PowerTechniques mags.

Fundamentals of resonance

Resonance is certainly one of themost interesting and most importantof electronic concepts. But there sureseems to be lots of helpline confusion

over what resonance can and cannotdo. Yes, you can produce incredibleenergy buildups in certain resonantcircuits. Destructive and even lethalones. Yes, you can extract this energy

if you want. No, none of the storedresonant energy is "free". Just as in apiggy bank, you can not take morequarters out than were put in.

At least I do not know how to do

59.2

Hardware Hacker

Fig. 2 – EXTENDED RESONANCE RESPONSE CURVES for a series RLCcircuit. Note the "flattening out" for frequencies well away from resonance.

FREQUENCY

DE

CI B

EL S

OF

AT

TE

NU

AT

I ON

0.1 f f 10 fo o o

Q = 5

Q = 1

0

Q = 2

0

Q = 5

0

Q = 1

00

Q = 2

00

∆

∆

∆

∆

∆

∆

f = 0.2

f = 0.1

f = 0.05

f = 0.02

f = 0.01f = 0.005

0

-10

-20

-30

-40

-50

-60

this, and 100% of all earlier attemptsat "free" resonant energy have failedmiserably. Most of these were noteven wrong. Let’s take a fresh lookat resonance fundamentals…

Figure one shows you the simpleseries combination of one resistor, aninductor, and a capacitor. This is aseries resonant circuit. Assume fornow that the resistance is your load,the inductor and capacitor are veryhigh quality, and the signal source isa very low impedance.

At extremely low frequencies, theinductor will look like a short circuitand the capacitor will appear as avery high capacitive reactance. Verylittle signal will reach the load.

Similarly, at very high frequencies,the capacitor will look like a shortcircuit, and the inductor will appearas a rather high inductive reactance.And once again, very little signal willreach the output load resistor.

At one certain frequency, though,

both of the inductive and capacitivereactances will be equal in strengthand opposite in sign, and will cancelout to zero, transferring all of yourinput signal to the output load. This"magic" frequency is defined as theresonance frequency.

As figure one does show us, theresonance frequency is determined bythe product of your L and C values.Resonant circuits are often frequencyselective. They allow you to tune to achosen frequency. This is how youselect any particular am or fm radiostation while you tune out all of theothers. Resonant circuits can alsostore surprisingly large quantities ofenergy. One very important energystorage use for resonant circuits is inthe deflection circuitry of televisionsets and computer monitors. Sneakyresonant switching tricks are used tosweep the beam back and forth whilerecycling the available energy.

The "Q" of a series resonant circuit

can get defined in several stunninglyunique ways. Q (standing for quality)could get defined as the ratio of theresonant inductive reactance to theload resistance. Or as the bandwidthbetween your -3 decibel half powerpoints. Or as a function of the ringingdecay time. Or as the amount of theresonant voltage increase you’ll getacross your inductor or capacitor. Oras determining the ratio of the storedto the dissipated energy per cycle.

All of these figure one definitionsof Q are identical, but they will leadyou to profoundly different uses andapplications for resonant circuits.

You change the resonant frequencyby shifting your LC product. You canchange the Q by shifting the LC ratio.

Figure two shows exactly how theresponse of series resonant circuitswill change with frequency and Q.The higher the Q, the narrower thefinal bandwidth between your halfpower (or 0.707 voltage amplitude)points. Note that each of these curvesstarts out by rising at +6 decibels peroctave, swings up through a sharpresonance peak, and then eventuallyends up falling at a -6 decibels peroctave rate. No matter how steep yournear-resonance dropoff, you reach apoint where either the inductor’s orthe capacitor’s reactance is too smallto make much difference.

If you need more attenuation wellaway from resonance, you usually arebest off adding extra series resonantpoles, or otherwise cascading.

You can quickly sketch most anyresonant curve. You should get zeroattenuation at the center frequency,and -3 decibels of attentuation at thehalf power bandwidth points set by1/Q. You then locate your resonantfrequency point "Q" (converted todecibels) down and sketch a pair of 6decibel per octave lines on downwardfrom there. Then smoothly connectall of the dots and the lines.

In high Q series resonant circuits,the usual reactive voltage across theinductor or capacitor will be manytimes that of the input. For instance, aone volt input at resonance and a Q of100 will produce a nasty 100 voltsacross the capacitor or the inductor.Some switching mode power suppliesmake use of this resonant rise for atransformer-free voltage increase.

The resonant voltage step up can

59.3

January, 1993

Fig. 3 – GURU GONZO POSTSCRIPT CODE used to create camera-readysemilog artwork for figure two. Only your favorite word processor is needed!

% Requires persistent download of GONZO15.PTL utility from GEnie PSRT.

guru save /snap1 exch def 200 300 10 setgrid % 30 30 showgrid

line1 1 setlinecap 10 0 mt 26 u 0 0 mt 26 pu 20 pr 26 pd 20 pl gsave line1 stroke grestoregsave clip newpath 0 setlinewidth 0 setgray

1 1 10 log 10 mul 0 moveto 0 28 rlineto stroke for 10 10 100 log 10 mul 0 moveto 0 28 rlinetostroke for 0 2 28 0 exch moveto 20 0 rlineto stroke for

/fnc dup dup mul 1 sub exch div dup mul Q dup mul mul 1 add sqrt log 20 mul neg def

/vsf 2.5 div 26 add def /hsf log 10 mul 10 add def /incperdec 200 def /startat 0.1 def

/wholecurve/Q exch def newpath /val startat def val dup fnc mt incperdec 2 mul 1 add val fncval hsf exch vsf lineto /val val 10 1 incperdec div exp mul def repeat 0.06 setlinewidth strokedef

[5 10 20 50 100 200] wholecurve forall grestore

/cstretch 0.01 def /sstretch 0.03 def /yinc 1 def

/font1 /Helvetica 0.85 gonzofont/font2 /Helvetica-Bold 0.85 gonzofont/font3 /Helvetica 0.7 gonzofont/font4 /Symbol 0.75 gonzofont/font5 /Helvetica [0.7 0 0 0.7 0 -.2] gonzofont/font6 /Helvetica [0 0.85 -0.85 0 0 0] gonzofont

/b+ gsave newpath /msg exch def translate 40 rotate 1 setlinecap white 0.8 setlinewidth font30 .3 mt msg stringwidth pop 0 add r black 0 0.1 msg cl grestore def

/b- gsave newpath /msg exch def translate -40 rotate 1 setlinecap white 0.8 setlinewidth font30 .3 mt msg stringwidth pop -1 add l black 0 0.1 msg cr grestore def /kern 0.1 def

font1 10 28.3 (FREQUENCY) cc -3.3 8 (|6DECIBELS OF ATTENUATION) cl

[line1 0 26 mt 0.5 u 10 3] xrpt [line1 0 2 mt 0.5 l 4 7] yrpt

0 26.9 (0.|k1 f|5o) cc 10 26.9 (f|5o) cc 20 26.9 (1|k0 f|5o) cc 1 13.6 (Q = 5) b+ 1 11.2 (Q = 10)b+ 1 8.8 (Q = 20) b+ 19 13.6 (|4D|3f = 0.2) b- 19 11.2 (|4D|3f = 0.1) b- 19 8.8 (|4D|3f = 0.05) b-19 5.6 (|4D|3f = 0.02) b- 19 3.2 (|4D|3f = 0.01) b- 19 0.8 (|4D|3f = 0.005) b- 1 5.6 (Q = 50) b+ 13.2 (Q = 100) b+ 1 0.8 (Q = 200) b+

font1 -.8 25.7 (0) cr -.8 21.7 (-10) cr -.8 17.7 (-20) cr -.8 13.7 (-30) cr -.8 9.7 (-40) cr -.8 5.7(-50) cr -.8 1.7 (-60) cr

snap1 restore showpage quit

easily become destructive if the inputsignal gets too big.

Just as a pendulum swaps kineticfor potential energy as it oscillates,the inductor stored Li 2/2 energy is ata maximum on current peaks, and thecapacitor stored Cv 2/2 energy is at amaximum on voltage peaks. Whilethe energy appears to swap back andforth between inductor and capacitor,your total stored energy over any onecycle remains constant.

One definition of Q is 2π times theenergy stored per cycle divided bythe energy dissipated per cycle. Thus,if you do have a Q of 100, a one ampinput and a one ohm load, at seriesresonance you will dissipate one wattper cycle while you store around 15.9watts per cycle.

Just where did the 15.9 watts comefrom? The same place the stash in thepiggy bank came from. It got built upearlier, a quarter at a time. During thetransient times when you first apply asignal, input energy slowly will getsaved, building up the inductor’s andcapacitor’s energy storage.

Very large amounts of energy canbe stored in resonant circuits. In thecase of a large color tv or computermonitor, as much as 5 kilowatts ofresonant power are involved in thehorizontal sweep circuitry. In a veryefficient circuit which continuouslyrecycles resonant deflection currents.More on this in the Hardware HackerIII reprints.

If you deliver an impulse to a highQ resonant circuit, it will ring for arundown time as shown in figure one.The higher your Q, the longer yourringing time. One obvious use is forelectronic chimes and gongs.

More on rundown times appears inmy Active Filter Cookbook.

Although I have shown a singleresistor in our resonant circuit, youreally have a load resistor, a sourceimpedance resistor, and the resistivelosses in the inductor. All of thesehave to be accounted for in the realworld. For a series resonant circuit tooperate, you must drive it from a verylow impedance source.

You can also create the dual of thisRLC circuit by placing everything inparallel, creating a parallel resonantcircuit. Any parallel resonant circuitreaches a very high impedance at itsresonance and operates only when it

is driven from a very high impedancecurrent source. Instead of voltagesmultiplying by Q, the reactive currentmultiplies by Q instead.

More on resonance fundamentalsappears in most electrical engineeringtexts. Such as Skilling’s ElectricalEngineering Circuits. And lots moreon working with and using resonantcircuits appears in my Active FilterCookbook.

PostScript to the rescue

At one time, drawing camera-readycharts and graphs such as figure twowas a real hassle. First you had tofind some semi-log paper and thentrace it to the correct resolution. Thenyou had to calculate all of the neededpoints. Finally, you had to ink themwith splines or French curves, messypens, and similar drafting tools. Finalsize and detail changes were a realbear. Especially if you had to stretchor shrink it in one direction only.

Even then, the editor might decideit’s not good enough and has to redothe entire figure from scratch.

These days, instead, you simplyuse that incredibly superb PostScriptlanguage to draw the whole job foryou. Instantly and hassle free.

PostScript is one totally generalpurpose and super friendly computerlanguage that is absolutely ideal formany hardware hacking tasks. One ofPostScript’s utterly minor and almostinsignificant capabilities is to dirty upotherwise clean sheets of paper.

In any way you like. Totally deviceindependently. So the same old wordprocessor text file you use for yourrough proof copy can also now bephototypeset. Interchangeably, onany brand of personal computer.

Figure three shows you the ultrasimple PostScript code required tocreate all the fancy semilog decibelresonance plots of figure two. Youjust shove this through your favoriteword processor and then send it to aPostScript printer using a two-waycomm setup. Ethernet, AppleTalk,Serial, or Shared SCSII comm will allwork just fine.

But never use a parallel port with

59.4

Hardware Hacker

Fig. 4 – THE N-CHANNEL POWER MOSFET is now the most popular andmost economical power switch in use today. Increasing the gate voltageabove its threshold value turns the device on.

Zero or low gate voltage letsP substrate remain that way,blocks source to drain current.

N

N

Pgate

drain

source

substrate

Positive gate voltage builds upelectrons, forms a continuousN-channel, and turns on.

N

N

P++++

-----

gate

drain

source

substrate

PostScript! To do so blindfolds youand ties both of your feet together.Many PostScript programs will notrun at all over a parallel port.

All you need to write PostScriptcode is your favorite editor or wordprocessor.

I have just posted a PostScript forHardware Hackers tutorial as #511NUTS9.PS to my GEnie PSRT.

Among the many hundreds of otherPostScript-as-language files, the fullSmith Chart drawing routines as file#367 SMITHCHT.PS and my printedcircuits as #401 PRINCRCT.GPS. ThePostScript startup secrets tutorial nowappears as #335 SECRTEMP.GPS andPostScript speedup secrets tutorial as#460 SPEEDUP.PS. Unique PostScriptcode to let you instantly draw all thecamera-ready figures in this columnappears as HACK59.GPS.

Finally, if you do not now have aPostScript printer, I’ve posted theGHOSTSCRIPT files to PSRT. Theselet you run PostScript with just aboutany printer. They also give you fullviewable display PostScript on anymonitor. The current PSRT bannerwill show you the latest GhostScriptversion numbers to use.

While figure two can easily bedone in "raw" PostScript, I’ve mademy coding even faster and simpler byopening a convenient and powerfullayout/illustration dictionary I use.

This file is #517 GONZO15.PTL andgets persistently downloaded at thestart of your work session. One single"guru" command opens up this set ofpower tools for you.

You can also write or call me for afree new PostScript secret resourcesmailer.

High side drivers

There’s a new game in town calledhigh side drivers that are becomingsuper important. A high side driver isa solid state relay placed between thepositive dc supply line and any loadsthat you wish to control.

Automotive people like high sidedrivers because only a single wire isneeded for each load with the chassisforming the ground return. Laptopand palmtop computer folks like highside drivers because the inputs andoutputs of the controlling circuits arenot hurt by any floating grounds.

Many high side drivers are smartenough to protect themselves againstshorts, overloads, and other faults.What gets tricky fast about high sidedrivers is that the preferred choice inany electronic switch today is the N-channel power MOSFET. To turn onan N-channel MOSFET that’s beenconnected to your positive supplyvoltage, you’ll need a gate controlsignal well above that of the supply.

Before we see just how we can get

a control signal that is well above thatof the most positive supply line, let’sbriefly review just what an N-channelMOSFET is and how it works. Figurefour shows details.

You start with a block of P-dopedsilicon. Add a non-rectifying or anohmic terminal to it, known as thesubstrate. Now you implant two N-channel wells in the substrate. Ohmiccontact these and call them the sourceon the bottom and the drain on top.Now, build a capacitor by adding asuperthin dielectric and a conductorbetween source and drain. Call thislead the gate.

If the gate is at a zero or negativepotential with respect to the source,there will be a zero drain to sourcecurrent, since the MOSFET looks likea pair of back-to-back diodes. Therewill also never be any steady stategate current, since all your gate everdoes is charge up or discharge a smallcapacitor.

Let the gate get somewhat positivewith respect to the drain. Electronshave to pile up on the substrate sideof the gate capacitor, so that area willbecome less of a P-type material. Letthe gate voltage exceed a thresholdvalue, and the extra electrons on thesubstrate side will actually change thesubstrate into a continuous N channelbetween source and drain. You nowhave three N regions tied togetherinto a solid block. These look like aplain old resistor and allow currentbetween source and drain.

Below the threshold voltage, you’llhave an open circuit between sourceand drain. Above threshold, you havea small resistor between source anddrain. A grounded gate turns you off.A gate above the threshold voltageturns you on. The typical threshold isaround +4 volts or so, but to reallyturn the device solidly on, a gate tosource voltage of +10 is preferred.

Unlike the NPN power transistors,there are no saturation effects or P-Njunctions in your main current path.There is also zero steady state gatecurrent needed. A turned on MOSFETacts as a plain old low value resistor.

Your "on" resistance of a singleN-channel MOSFET isn’t really thatgreat. For instance, in the CMOS 4066quad analog switch, the on resistanceis a high 16 ohms or so. To beat this,power MOSFETS are really hundreds,

59.5

January, 1993

Fig. 5 – A DUAL HIGH SIDE DRIVER. The left side is shown as a simplepower relay, while the right side includes "slow blow" current sensing and anauto breaker reset. The boosted gate voltages are internally generated.

1 2 3 4

8 7 6 5

DS1 G1 GND IN1

DS2 G2 VS IN2

LTC1155

leftcontrol

rightcontrol

LEFTPOWERLOAD

RIGHTPOWERLOAD

N-channelpower FET

N-channelpower FET

100K

100K

0.1 F 0.020for 5 Amptrip limit

+vcc +vcc

+vcc

vcc can rangefrom +4.5 to +18.

right rep ratesets reset time

µ Ω

or even thousands of tiny MOSFETtransistors all internally connected inparallel.

There are lots of sources of powerMOSFET chips. Motorola, Siliconix,Texas Instruments and InternationalRectifier are typical. Because of theirquite low cost and high gain, thesehave become the main power switchof choice for many electronic uses.Although there are also P-channelMOSFETs, they do cost more and areless efficient. And because of certainfundamental device physics, they arelikely to remain so.

Since a turned on power MOSFETis really nothing but a resistor, it doesnot matter which direction the maincurrent goes. If you do the obviousand make the drain go positive withrespect to the source, you are said tobe in quadrant I. On the other hand,if you make the drain negative withrespect to the source, you end up inquadrant III. High side drivers workin quadrant I. But most synchronousrectifiers which use MOSFETS willnormally run in quadrant III to avoidsubstrate diode conduction.

To use a N-channel MOSFET as ahigh side driver, you just connect thedrain to the positive supply, and yoursource to the load being controlled.To turn the switch off, you leave thegate at or below the positive supplyvoltage. To turn the switch on, youconnect the gate to a value well abovethat of your positive supply, typicallyby +10 volts or so.

Where on earth do you get an extrasupply that is well above your mainsupply voltage? Quite little averagecurrent is needed since you are onlycharging or discharging a small gatecapacitor. A number of new low costintegrated circuits are now availablewhich use charge pumps and similarcircuit tricks to let you reliably applyN-channel MOSFETS for high sidepower switches. Typical examples doinclude that International RectifierIR2125, the Maxim MAX620, and theLinear Technology LTC1155.

The LTC1155 is a very interestingchip. This gives you a self-protectingpair of micropower dual high sidedrivers in a single eight pin mini-DIP.A dual high side circuit breaker isshown you in figure five.

Here is how either half of thiscircuit works: A built-in charge pump

continuously generates a referencevoltage above the postive supply.

Leaving IN1 low leaves your loadunpowered. Raising IN1 to a TTLlogic one (+2 volts or higher) turnson your load. The load gets turned onby supplying the boosted gate voltageto the power MOSFET. With a fivevolt supply, your boosted voltage isaround +12 total, or around +7 abovethe supply. Higher boost voltages aregenerated for higher value supplies.

The load power normally stays onuntil IN1 drops to a logical zero under0.8 volts. There’s also a protectioninput known as DS1. If DS1 ever getsmore than one tenth of a volt belowthe supply, it automatically shutsthings down. You can add a loadsensing resistor of one tenth of a voltper amp to shut down on anyovercurrent as shown.

Some loads might have large butexpected inrush currents. This oftenhappens with incandescent lamps andsolenoids. A resistor and capacitortime delay can be added to the currentsensing to allow inrush currents butstill react to overloads. This simulatesthe operation of a slow blow fuse.See the LTC1155 data sheet for moredetails. Many other innovative circuitexamples are included.

Be certain that your inrush filtercapacitor goes to the positive supplyand not to ground!

A snap action gets involved on acircuit overload. Once any overloadoccurs, the input must be brought lowand then back high again to repower.This can be done either manually orautomatically.

Switching times are fast but notstunning. The turn-on time is aroundhalf a millisecond. The usual turn-offtime is around 32 microseconds.

Note that any simple exclusive-ORgate could get used for external faultdetection. If the on command is highand your load is low, you have anoutput short. If the on command islow and the load is high, you have anoutput open. If both are low, youhave a normal switch turn-off, and ifboth are high, you’ll have a normalswitch turn-on condition.

The standby current when off is amere 8 microamps, making this idealfor battery saving applications.

Lots of additional details on analogswitches are in my CMOS Cookbook.

You’ll be seeing lots more on highside drivers as they are one of thehottest of new electronic applicationsareas. What unusual or off-the-walluses for these can you think of?

59.6

Hardware Hacker

SEMICONDUCTOR RESOURCES II

Gould AMI2300 Buckskin RoadPocatello, ID 83201(800) 538-7736

Harris Semiconductor2401 Palm Bay RoadPalm Bay, FL 32905(305) 724-3739


Hitachi2000 Sierra Point PkwyBrisbane, CA 94005(415) 589-8300

Hughes Aircraft500 Superior Ave M/S B1250Newport Beach, CA 92658(714) 759-2727

Hyundai166 Baypointe ParkwaySan Jose, CA 95134(408) 473-9200

Intech67 Alexander DriveResearch Triangle, NC 27709(919) 549-8411

Integrated Circuit SystemsPO Box 968Valley Forge, PA 19482(215) 666-1900

Intel1000 Business Center DrMt. Prospect, IL 60056(800) 548-4725

Internat’l Microcircuits525 Los Coches StreetMilpitas, CA 95035(408) 263-6300

Internat’l Micro ElectronicsPO Box 170415Arlington, TX 76003(817) 561-2244

Lambda121 International Blvd.Corpus Christi, TX 78406(512) 289-0403

Lattice Semiconductor5555 NE Moore CourtMt. Prospect, IL 60056(800) FAST-GAL

Linear Technology1630 McCarthy Blvd.Milpitas, CA 95035(408) 432-1900

LSI/CSI1235 Walt Whitman RoadMelville, NY 11747(516) 271-0400

LSI Logic1551 McCarthy Blvd.Milpitas, CA 95035(408) 433-8000

Maxim Integrated Products120 San Gabriel DriveSunnyvale, CA 94086(408) 737-7600

Micrel Semiconductor560 Oakmead ParkwaySunnyvale, CA 94086(408) 245-2500

Microchip Technology2355 W. Chandler Blvd.Chandler, AZ 85224(602) 963-7373

Micro Linear2092 Concourse DriveSan Jose, CA 95131(408) 433-5200

Micron Technology2805 East Columbia RoadBoise, ID 83706(208) 386-3900

Micro Power Systems3100 Alfred StreetSanta Clara, CA 95054(408) 727-5350

Micro Switch11 West Spring StreetFreeport, IL 61032(815) 235-6600

Mitel2321 Morena Blvd Ste MSan Diego, CA 92110(619) 276-3421

Mitsubishi1050 East Arques AvenueSunnyvale, CA 94086(408) 730-5900

MotorolaPO Box 1466Austin, TX 78767(800) 521-6274

MX-Com4800 Bethania Station RdWinston-Salem, NC 27105(800) 638-5577

National Semiconductor47 Ellis StreetMountain View, CA 94043(800) 632-3531

NCR Microelectronic3718 North Rock RoadWichita, KS 67226(800) 325-SCSI

NEC ElectronicsPO Box 7241Mountain View, CA 94039(800) 632-3531

More semiconductor houses

This month, we will continue ourmulti-part resource sidebar listing ofsemiconductor houses, picking upGould through NEC. I have left offsome of the more obscure outfits thatdon’t seem too innovative.

General Electric, Intersil, and RCAare now part of Harris. A few of theirbetter chips remain available.

Similarly, the Sprague folks havenow become Allegro, Amperex hassold out to Philips, and the dregs ofMostek were long ago absorbed intoSGS. General Instruments has movedacross the country and all their goodsound effects chips fell off the truckon the way. Most of the low volumepower semiconductor houses are nowchanging their names so fast it is hardto keep up. See PCIM and similartrade journals to find just out who iscurrently calling themselves what inthis specialty area.

Laser repair training bargain

Canon Inc. manufactures by far themost popular laser printer engines inuse today. Hewlett-Packard, Apple,QMS and several of the other majorplayers all use Canon engines in theirlaser printers.

Of these printers, by far the mostpopular mid-range units all will usethe Canon SX engine. And by far thelargest single repair item on all thesemachines is cleaning and repair of theSX fusion assemblies. The stuff thattypically goes wrong with SX fusionassemblies are the scored or swollenrollers, broken or burned out quartzheater lamps, worn or tooth-missinggears, dirty or defective temperaturesensors, feed creasing and jamming,or general grunge accumulation.

Don Thompson of TechniGraphicshas long offered the very finest laserprinter repair training. He recentlysent me a sample of his new SX FuserAssembly Master Kit, and has agreedto offer it to Electronics Now readersat a very special price $350.

For the price of one new fusionassembly or one single fusion repairfrom a typical computer dealer, youget a complete set of all the qualityhand tools and supplies required tobecome a fusion rebuilding expert; atwo hour lucidly detailed videotape;secret insider info on the "tye wrap"

59.7

January, 1993

NAMES AND NUMBERS

ASD/AMD Trade News2525 Ocean Park BlvdSanta Monica, CA 90405(800) 421-4511

Asian Sources/Wordright1020 Church StreetEvanston, IL 60201(708) 475-1900

Bell System Tech Journal101 John F. Kennedy ParkwayShort Hills, NJ 07078(201) 564-4454

Cherry Semiconductor2000 S County TrailEast Greenwich, RI 02818(401) 885-3600

Dallas Semiconductor4401 S Beltwood PkwyDallas, TX 75244(214) 450-0448


EG&G Reticon345 Potrero AvenueSunnyvale, CA 94086(408) 245-2060

Garden Fresh ReplicasPO Box 208Neosho, MO 64850(800) 545-7304

GEnie401 N Washington StreetRockville, MD 20850(800) 638-9636


Industrial Market Place7842 N Lincoln AvenueSkokie, IL 60077(800) 323-1818

International Rectifier233 Kansas Street El Segundo, CA 90245(310) 322-3331

Linear Technology1630 McCarthy BlvdMilpitas, CA 95035(408) 432-1900

Maxim120 San Gabriel DriveSunnyvale, CA 94086(408) 737-7600

Motorola5005 E McDowell RoadPhoenix, AZ 85008(800) 521-6274

SiliconixPO Box 54951Santa Clara, CA 95056(408) 988-8000

SpeleonicsBox 5283Bloomington, IN 47407(812) 339-7305

Texas InstrumentsPO Box 809066Dallas, TX 75380(800) 336-5236

Don Thompson23072 Lake Center Dr #100El Toro, CA 92630(714) 855-3838

Trade WinnersPO Box 2868Vancouver, WA 98668(206) 694-1765

spring retainer method; a personaltech help hotline; and replacementparts for just about everything thatcan go wrong with these units.

Individual bits and pieces are alsoeconomically available as needed tocontinue your own fusion rebuildingenterprise. Most other sources willsell only complete assemblies.

Rebuilding kits for other printersand most other fuser assemblies arebeing offered.

Far East sources

I continually get helpline calls forhardware hackers who seek Far Eastcontacts for computers and electronicassemblies and custom work. Wehave already seen that Trade Winnersis one possible resource. This is sortof a Hong Kong Computer Shopper,only wholesale.

But I may have found the motherlode. There’s now a Hong Kong tradejournal publisher by the name ofAsian Sources who publish sevenmagazines, one each for computers,electronics, electronic components,timepieces, fashion accessories, homeproducts, and "hardwares". The latteris apparently their term for machineryand industrial supplies. Yes, they areall printed in English.

These cost $70 each per year viasurface mail. But they do offer freesamples on a one-sample-per-requestbasis. Per their bingo cards.

New tech lit

From Dallas Semiconductor, a fatnew 1993 Product Data Book. Full ofexciting, innovative, and very usefulhacker chips. Mostly timers, clocks,non-volatile memory, smart sockets,telephone and security stuff.

Through Cherry Semiconductor, anew data book on automotive, sensor,motor controlling, and power supplycircuits. And from Reticon, a SolidState Camera Products data book.

The Industrial Marketplace is agreat tabloid shopper with lots ofoutstanding surplus offerings and fullauction listings. Mostly mechanicaland machine shop stuff, but definitelysome electronics. I get the impressionthat this is the wholesaler’s surplusinsider’s mag.

Another interesting and readablesurplus shopper mag is the ASD/AMDTradeNews. But it does not strongly

emphasize electronics.Replica kale is newly offered by

Garden Fresh Replicas.Free samples of their new AlInGaP

lamps are available through HewlettPackard. These are incredibly brightLED’s visible in direct sunlight. Andintended for eventual use as auto taillights and turn signals. These are thefirst LED products with efficienciesabout the same as an incandescentlamp. A detailed discussion of thisnew technology appears in the curentissue of Speleonics.

I’ve recently posted a thorough andcomplete list of inventor’s resourcesto PSRT as #520 INVENORG.PS. Alsosee #477 NOPATENT.PS. We’ll havesome more info on inventions and

inventing in a future column. Manyother of my PostScript programmingexamples are also uniquely availablein this PSRT library. Your averagedownloading costs are around twentyone cents.

Sorry for the inexcusable delays,but I’ve at long last gotten my newIncredible Secret Money Machine IIbacklog worked off. I am currentlyshipping autographed copies of thisnewly revised guide to forming yourown small scale tech, craft, or artistic venture.

As usual, we’ve shown most of thementioned resources in our Names &Numbers or IC Resources sidebars.Be certain to check here first beforecalling our tech helpline.

59.8

Hardware Hacker

Don Lancaster’s

February, 1993

Hardware HackerRelaxation oscillators

Newtek’s video toasterBroadcast trade journals

Syncronizing video sourcesElectric Discharge Machining

60.1

Fig. 1 – NEWTEK’S VIDEO TOASTER 2.0 can be used to cheaply replace asmuch as $100,000 worth of video editing and post-production equipment,while still offering full network broadcast quality. Best results are obtained withfancier video formats that allow single frame writes.

programmonitor

previewmonitor

overlaymonitor

NEWTEK VIDEO TOASTER

recordingVCR

externalvideo

externalvideo

externalvideo

externalvideo

internalframe A

internalframe B

internalcolor

#1 #2 #3 #4

This month, we seem to havea pair of really exciting newopportunities from oppositeends of the broad hardware

hacking spectrum. Before we begin,though, our usual reminder that youcan pick up technical help, consultantreferrals, and off-the-wall networkingby calling me per the box below.

Or by accessing our superb GEniePSRT which has just seen its 40,000thlibrary download. You can voice call(800) 638-9636 for connect info.

Let’s start off with…

Newtek’s Video Toaster

Tim Jenison recently sent me oneof his Newtek video toasters to playwith. What follows is just some of mypreliminary impressions and randomcomments, rather than a thorough orunbiased review…

Their video toaster is basically anAmiga computer having some specialsoftware, a plug-in card, and severalextra jacks on the back. At a streetcost of $2000 (card only) or $4000 to$5300 (a full slow or fast system), the video toaster can replace somethinglike $100,000 worth of real broadcastquality video postproduction editingequipment.

Not imitates. Replaces outright. Oreven totally blows away.

In theory, you can now cheaplyand quickly produce total broadcastquality videotapes in your own home.The present genlocking and switchingabilities of the video toaster do seemthree years or so ahead of anythingMac based, and eons beyond anythingusing an IBM or PC platform.

The video toaster performance isabsolutely and totally stunning. Butlet’s knock it anyway. Just so you are sure what you are getting into.

First, if you just want to slap sometitles or computer art onto any oldhome video, that virtually unknown$129 Apple II Video Overlay card ismuch cheaper, surprisingly powerful,and vastly easier to use. A2 Central isone continuing source.

Second, you do not simply dropthis beast down on your kitchen table.

An entire room dedicated exclusivelyto the video toaster is your minimumpossible workspace. Although quitecompact by itself, the toaster oftenwill attract bulky and expensive hightech goodies like a huge magnet.

Third, plain old VHS is flat out notsuitable for any serious production orediting. Period. One big reason is thegeneration loss effects where copiessimply are not as good as an original.Another is the inability to selectivelyedit a single frame. Writing a singleframe gets essential for any animatedsequence. Many of the toaster’s moreexotic features are definitely not VHScompatible. No way.

Yes, you can handle fairly fancyproduction with the latest of SuperVHS or Hi-8. But if you’re in the least

serious about creating a commerciallymarketable product, a minimum ofSony Betacam should probably getused for your taping and editing.

Fourth, by the time you pick up a"real" camera or two, a "real" VCR ortwo, the three quality color monitorsrequired, the two time base correctorsdemanded for the VCR’s, your stationsynching genlock, an extra ac circuitbreaker, your storyboards, and somesupport furniture, your price for thetoaster itself does not seem to matterall that much.

Fifth, the toaster does not addressany audio mixing or processing. Itsimply passes the audio on from inputtape to output tape. There’s sort of anunbalance here, since the toaster doesso much so well on the video tracks.

60.2

Hardware Hacker

Fig. 2 – AS WITH ANY VIDEO EDITING SETUP, all input VCR’s must be timebase corrected, and all input video sources must be carefully synchronizedtogether. This arrangement uses Camera #1 for your station sync.

VCR editsource #2

VCR editsource #3

time basecorrector

genlocksynchronizer

time basecorrector

genlocksynchronizer

camera editsource #1

camera editsource #4

camera #1 outputsits station syncto edit sources#2, #3, and #4

sync out sync in

Video input sources to Newtek Toaster

Yet it almost completely ignores theaudio side.

Finally, the toaster has a very steeplearning curve. Bunches of time andeffort are required to do the job right.Just because your toaster potentiallycan do full broadcast quality doesn’tmean that you still can’t create totallyand utterly atrocious results.

So, what is in the box?

Figure one shows a typical toasterconfiguration. The toaster card andsoftware consists of nine very fancysubsystems. These are the switcher,the keyer, the framestore, the chromaFX processor, digital video effects, acharacter generator, a ToasterPaintdrawing program, the Lightwave 3Dmodeling program and the genlock.

The production switcher forms theheart of the system. There are threebuses, called the program bus, whichis your current output, your previewbus, which often will be your futureoutput, and the overlay bus, whichoften determines how your previewand future outputs will be combined.

Each bus can get manually or elsesoftware connected to seven differentsources. These include four live videoinputs, two still picture frames, or abackground color.

Say you want to switch from livevideo to a color title screen. To do aninstantaneous switching, you wouldput the live video on the program bus,the title art on the preview bus, andpress the take button. To do a manualgradual fade, there’s a large mousecontrolled "T" handle which lets yougradually change between the two.There’s also lots of preprogrammedwipes and fades available. Either inmanual or 3-speed automatic. Plusyou can write your own font softwareor use third party effects.

It gets complicated from there, butyou can easily do picture-in-picture,and pretty much every other specialeffect that you’ll see on a network orcable program. A full animation iscertainly possible. But only when youuse those video formats and controlhardware that let you do single framewrites under exact control.

The luminance keyer lets you putlive action over a fixed background.As a selected "white" or "black" levelgets tripped, your switcher instantlychanges between the action and thebackground. The frame grabber doeswhat you would expect: freezing aninstant of live video for future use.

Except that it actually grabs fourfields at once. This is needed becausethere are two fields per frame and twoframes used for the NTSC color phasesequence. A number of options areavailable to remove any blurring ormotion in any particular field.

The chroma FX processor lets youdo all sorts of neat color stuff, whilethe digital video effects give you lotsof wowie-gees like sliding, spinning,zooming, or a spherical mapping. Allof which is software programmable.The key to all these effects is to reachinto a RAM memory and address it ina nonobvious manner.

The character generator is used toplace messages upon your screen. Itoffers some very fancy special effectsincluding glitter, highlights, chromes,drop shadows, etc…

ToasterPaint is a powerful drawingprogram, while the Lightwave 3-D isa sophisticated image rendering andanimation system. Once again, youractual animation is only useful on thevideo standards and support hardwarethat allows single frame writes. Youranimation sequences can be up to 120frames, or four seconds long.

Ah yes, that genlock. When youtake any old pair of video sources andtry to switch between them, you willget a horrible and useless glitch. Theonly way around this is to make surethat each of your video sources getscarefully locked to the exact sametiming. By an exact lock, this meansthat all horizontal lines must startprecisely at the same instant and lastexactly the same time. Your colorphase on all the lines must preciselymatch. The vertical synchronizationpulses must be precisely aligned. Andfinally, those four NTSC color phasefields must be in precisely the correcttime sequence.

Now, if you have one single livevideo camera source or one singleoff-the-air live video broadcast, yourtoaster will automatically lock all ofits effects. Genlock here should be noproblem. But any other combination

60.3

February, 1993

Fig. 3 – ELECTRIC DISCHARGE MACHINING uses a spark to literally blastcraters out of a workpiece. The dielectric fluid washes the dregs away aftereach spark. Surprisingly, sub mil accuracies and microinch finishes are easilyand cheaply possible. The trick is to use lots of sparks and tiny craters.

TOOL

DIELECTRIC

FLUID

WORKPIECE

of sources needs careful thought as tohow your genlocking is done.

Most VCR’s introduce a second bigproblem, even if you are only usingone of them. Mechanical differences,alignment changes, and tape stretchmight slightly but continuously jitterthe timing coming off a prerecordedsource. A twenty nanoseconds erroris noticeable.

To clean up the output from anyrecorder, one or two steps might beneeded. A time base corrector simplyeliminates jitter. If you are using onerecorder as your only video source,then a plain old TBC will suffice. Onthe other hand, if you are using twoor more video sources, your recorderoutput will have to route through amuch fancier combination TBC andframe synchronizer.

Typical low end TBC’s include theDigital Processing VT-2000 and theIden TR-7. Fancier TBC/synchronizerdevices do include the Hotronic AP41and the Iden IVT-7. The typical streetpricing ranges from $750 up to $1600.With widely expanding markets, it’slikely that these prices should soondrop dramatically.

Grass Valley Group and Ikegamaoffer full broadcast quality switchers,synchronizers and correctors. And sodoes Sony. These are not cheap.

At any rate, if you want to usemultiple video sources, you pick yourabsolute best source and use it for thestation sync. Additional sources thataccept external synchronization canbe cable connected to this one stationsync source. Sources that cannot beexternally synchronized have to go totheir own TBC/synchronizers, whichin turn are cable connected to yourstation sync.

Figure two shows you a typicalsynchronization hookup. Rememberthat all recorders must be time basecorrected, and that only one source isallowed to provide station sync. Allother sources must be locked.

One more time: All VCR’s need atleast time base correction, and all ofyour video sources must get preciselylocked together for the toaster or anyother video production system.

What’s wrong with it?

While the current 2.0 version of thevideo toaster is a stupendous product,I feel this certainly could be further

improved. Firstoff, a true Mac basedversion is a must. Commodore mayhave a temporary and illusory lead ongenlocking, but the Mac color imagegeneration and editing has long agopassed up the Amiga (and everybodyelse) like they were sitting on blocks.Obvious examples do include Pixar’sRenderman, Apple’s own QuickTimeand Adobe’s Photoshop.

Newtek’s new Mac Desktop VideoGateway is a good first step towardsfull Mac compatibility.

Speaking of Adobe, some toastercompatibility with their PostScriptlanguage and its Carousel offspringsure would be useful. PostScript isideal for most video artwork, eitherregular or animated. While the publicdomain GhostScript (now availablecheaply on my Genie PSRT) could beimmediately used, a genuine AdobeDisplay PostScript is the best choice.PostScript type I and type III fontsare ludicrously better than the currentcrop of toaster characters.

Full compatibility with Kodak’snew PhotoCD technology is also amust. As is better audio processing;full support for wavelet, fractal, andthe MPEG compression options; andimproved time code use.

And their toaster would be evenmore useful if some other technicalimprovements can come down. Likefiguring out a method to effectivelysingle frame edit plain old VHS. Or

getting true read/write CD ROM outof the starting gate. Or speeding upthe CD ROM access by a hundred ormore. Probably the best way to dothis is with multiple heads and somesort of holographic sensing. Orangeor (sigh) blue laser diodes would alsohelp considerably with their shorterwavelengths and higher densities. Aswould a giant two-port buffer.

The price of time base correctorsand synchronizers also has to dropbunches. But this will surely happenas this market expands. We also needa newer GoVideo like product havingmultiple genlocked and single framewritable recorders all in one low costsystem package.

Also needed are lots of improved"on the fly" techniques similar to aninstant replay. Where a full minute ofRAM based video could be instantlysynchronized with and then real timeoverlain to any video format.

Who needs it?

Judging by all of the people whoimmediately piled up on my doorstepon the mere rumor I was getting one,pretty near anybody. In fact, yourchances are good that "Wanna playwith my toaster?" is now the numberone singles bar pickup line.

Its amazing who your friends are.Let’s see who was on the pile. Phil

runs the alternate cable service hereand is about to offer ultra-cheap local

60.4

Hardware Hacker

Fig. 4 – FOUR POPULAR VARIATIONS on Electrical Discharge Machining.

(A) Die Sinking EDM

tool

workpiece

(B) Wire EDM

takeupreel

supplyreel

workpiece

cutting wire

(C) Small Hole EDM

workpiece

tool

(D) Metal Disintegrator

workpiece

vibrator

tool

ads. Diane is the public informationofficer (a.k.a. the directorate of theministry of propaganda) for a federalbureaucracy. Henry now consults fora university multimedia department.Craig is a timber management type.Kathy is big into theater arts. Bee isinto how-to papermaking. Irene sellsweaving and loom stuff.

Boyd shoots rodeo events. Dan isheavy on his computer servicing. Jeffnow publishes a high-tech magazine.And Chris is shooting fire departmentsprinkler hookup videos. Myra is nowbusy networking all her regional Bedand Breakfasts. Mike is editing downhis UFO stuff. Jay has been making abig flap in avian raptor research. Alsobirds. Keith is the honcho of a largeregional rent-a-vid chain. And I amproducing PostScript intro videos.

To get started off with the Newtekvideo toaster, first get a copy of the

mind-blowing free video demo, eitherby calling them or circling the bingocard. Newtek also has an outstandingtech support helpline. One of manyretail toaster sources is B & H Video,who also stock TBC cards.

The leading mag is Video ToasterUser, while Coffee and Toast is oneinteractive video service. One sourcefor toaster fonts is Kara ComputerGraphics, while public domain disksof toaster effects are available at $6each from Timmins/Kingsway.

Two associates of mine who offercustom video editing work and postproduction include Limel Schneikerof HDS Systems (for Mac based apps)and Boyd Bairn of Rodeo Video (forSony Betacam).

Electric Discharge Machining

EDM, otherwise known as sparkmachining has held a rather obscure

corner in the odd world of industrialelectronics. But EDM has recentlymoved out of the toolroom and ontothe production floor. There’s nothinginherently expensive or complicatedabout EDM. It has some great newhacker potential. Especially since itlends itself so well to CAD/CAM andcomputer control.

Figure three shows you the basicidea. You place a workpiece of metalto get machined under a normallyrecirculating and insulating dielectricfluid. While kerosene was originallyused, deionized water with a polymerresin is more popular today. You thenbring a tool close to but not touchingyour workpiece and then discharge acapacitor between the two.

Which creates a spark.The spark vaporizes a volume of

the dielectric and blasts a crater outof the workpiece, creating a liquidmetal puddle. After the spark ends,the puddle solidifies and the movingdielectric washes the dregs away. The"dirty" electrolyte is then filtered andrecycled for reuse.

The process is repeated zillions oftimes. The next arriving spark strikessomewhere else, since the crater justincreased the average spacing. As theworkpiece erodes, the tool can getlowered somewhat. Eventually, theworkpiece should assume the exactshape of the tool. Servo controls cansense the spark intensity and controlthe descent rate, making sure that anoptimum spacing between a tool andworkpiece is held.

Although spark machining soundsrather crude, EDM can easily do ultrasmooth microinch machining havingaccuracies to a fraction of a mil.

Figure four shows several popularvariations. With die sinking EDM, amaster pattern is "pushed" into theworkpiece. The tool can be arbitrarilycomplex and virtually any shape solong as there are zero undercuts. WireEDM works sort of like a bandsaw.You start with a supply reel of brassor other wire above your work andhave a takeup reel below the work.The speed is adjusted so that the wirewill erode and get "used up" at anacceptable rate. Wires are typicallyfrom two to ten mils in diameter.

With small hole EDM, tiny holescan be "drilled" very deeply and veryaccurately. One obvious use for small

60.5

February, 1993

EDM (SPARK MACHINING) RESOURCES

Alsop EngineeringPO Box 3449Kingston, NY 12401(914) 338-0466

American Machinist1100 Superior AvenueCleveland, OH 44114(216) 696-7000

Barnes/RaymondPO Box 586Maumee, OH 43537(800) 228-1156

Belmont Equipment Co32035 Edward AvenueMadison Heights, MI 48071(313) 588-7011

Ebbco, Inc35500 Mound RoadSterling Heights, MI 48310(313) 268-7000

EDM Today1212 State Route 23Butler, NJ 07405(201) 838-3130

Gisco100 Laser CourtHauppauge, NY 11788(516) 273-5353

Hansvedt Industries803 Kettering ParkUrbana, IL 61801(217) 384-5900

Hurco ManufacturingOne Technology WayIndianapolis, IN 46268(800) 441-1036

Ingersoll1301 Eddy AvenueRockford, IL 61103(815) 654-5800

Lindsay PublicationsPO Box 538Bradley, IL 60915(815) 935-5353

Metlfax29100 Aurora Rd, Ste 200Solon, OH 44139(216) 248-1125

Mitsubishi EDM1500 Michael DriveWood Dale, IL 60191(708) 860-4210

Sodick Inc710 Cooper CourtSchaumburg, IL 60173(708) 310-2600

TRC Electronics2216 West 16th StreetBroadview, IL 60153(708) 681-1810

US EDM Systems7960 S Roberts RoadBridgeview, IL 60455(800) 837-6808

Fig. 5 – THE CLASSIC NEON LAMP relaxation oscillator. The lamp flashesseveral times a second. Some EDM circuits use a much faster and far morepowerful version of this circuit, substituting the tool spark gap for the neongas breakdown.

+120 vdc

1 Meg

NE-20.1 µF

hole EDM is for drilling pilot holes tostart an internal path wire for EDMmachining process.

Finally, a metal disintegrator is acoarser EDM process which uses avibrating electrode and an arc welderto literally blast some holes into yourworkpiece. Important uses are toremove snapped studs, stuck taps, orbroken drills.

There’s several unique advantagesto EDM. The tool can be much softerthan the workpiece, so you can nowroutinely use brass, copper, or carbonto cut up hardened steel, titanium, orcarbide alloys. Ideally, there is zerotool contact, so there is no friction,chatter, or side loading.

By chosing the correct dischargepolarity, the workpiece erodes muchfaster than your tool. Since you cannow temper or harden the workpiecebefore you machine, the final resultscan end up more accurate.

Those EDM tool paths can be verycomplex. You can easily pull suchtricks as "drilling" a deep and blindsquare hole that has sharp bottomcorners. With wire EDM, a punch anda die can be simultaneously cut froma single piece of steel, guaranteeing a perfect fit with exact clearances.

The disadvantages to EDM? Boththe tool and your workpiece must beconductors. Tool life is fairly short.And the machining rates are ratherslow, say a cubic inch an hour for diesinking or thirty square inches perhour for wire EDM. Thus, a job maytake overnight, even using stackedwork and multiple heads. But thiseasily automated process can be donelargely unattended.

The voltages and currents neededare not that big a deal. Since your arcis less than a mil long, 80 volts or sois all you usually want. Typical EDMpower needs are several kilowatts. Orroughly the same as a larger millingmachine or lathe.

Spark repitition rates are usually20,000 to 500,000 sparks per second.

Most EDM circuits use a variationof the simple relaxation oscillator.Sort of a big brudder to the neon lampflasher circuit we have shown you infigure five.

In any relaxation oscillator, yourcapacitor will slowly charge up to itscritical voltage which breaks down orturns on some nonlinear switch such

as the gas plasma or the breakdownof a tool’s spark gap.

The capacitor normally continuesdischarging at high current until it

drops below a current threshold. Atthat point, your gas deionizes or thespark quits, and the capacitor is freeto once again begin recharging. The

60.6

Hardware Hacker

NAMES AND NUMBERS

Analog Devices1 Tech Way, PO Box 9106Norwood, MA 02062(617) 329-4700

A2 CentralPO Box 11250Overland Park, KS 66207(913) 469-6502

B&H Video119 West 17th StreetNew York, NY 10011(800) 932-1977

Black Book Auction ReportPO Box 758Gainesville, GA 30503(706) 532-4111

Digital Processing Systems11 Spiral Drive, Suite 10Florence, KY 41042(606) 371-5533


Grass Valley GroupPO Box 1114Grass Valley, CA 95945(916) 478-3000

HDS SystemsPO Box 42767Tucson, AZ 85733(602) 881-2632

Hotronic1875 S Winchester BlvdCampbell, CA 95008(408) 378-3883

I.DEN9620 Chesapeake Dr, Ste 204San Diego, CA 92123(619) 492-9239

Ikegami37 Brook AvenueMaywood, NJ 07607(201) 368-9171

Kara Computer Graphics2554 Lincoln Blvd, Ste 1010Marina Del Rey CA 90291(310) 578-9177

NewTek215 SE 8th AvenueTopeka, KS 66603(800) 765-3406

Radio World5827 Columbia Pike, Ste 310Falls Church, VA 22041(703) 998-7600

Rodeo VideoPO Box GSnowflake, AZ 85937(800) 331-1269

Sierra2075 N Capitol AvenueSan Jose, CA 95132(408) 263-9300

SynergeticsBox 809Thatcher, AZ 85552(602) 428-4073

Timmins/Kingsway2427 Hart AvenueSanta Clara, CA 95050(408) 244-9692

Toast & Coffee12219 Nicollet Avenue SBurnsville, MN 55337(612) 890-2189

TRWBox 2472La Jolla, CA 92038(619) 475-1000

TV Technology5827 Columbia Pike, Ste 310Falls Church, VA 22041(703) 998-7600

Video Toaster User21611 Stevens Creek BlvdCupertino, CA 95014(408) 252-0508

cycle then repeats.Typical EDM capacitors are in the

50 microfarad region. The value ofthe capacitor determines the size foreach spark crater, thus trading off thesmoothness against the cutting time.High quality capacitors having a lowESR series resistance are an absolutemust. Electrolytics are a no-no.

An EDM machine can also be aspark gap transmitter that generates a

horrendous amount of very bad radiointerference. The usual shielding andother tricks are a must to get RFIdown to acceptable levels.

In modern EDM, triacs or otherelectronic switches can speed up andimprove the operation of the simplerelaxation oscillator. But the idea isstill the same. Charge a capacitor tospark breakdown. Then discharge thecapacitor into the spark gap. Repeat

the cycle over and over again. Sparktimes and duty cycles are adjustableover a wide range.

As our resource sidebar for thismonth, I’ve gathered together someplaces to go for more info on EDM.The leading trade journal is calledEDM Today, while ads and articlesoccasionally show up in AmericanMachinist and Metalfax. Besides allthe other great machinery and homeshop books, the Lindsay Publicationsfolks offer a Practice and Theory ofElectrochemical Machining, and theRamah Machine Metal Disintegrator.Several other resources listed form arandom sampling of higher profilemanufacturers and distributors forEDM machinery and supplies.

Let’s have your thoughts on newlow cost hacker EDM opportunities.There should be lots of exciting newpossibilities here. Especially with thelatest of electronic switching powersupply techniques.

New Tech Lit

There’s loads of interesting newchips piling up. Particularly the Ariasound circuits from Sierra, or thatnew TMC22190 digital video layeringengine and the TMC22070 genlockingvideo digitizer from TRW.

A multimedia stereo audio mixerap note is now offered by the AnalogDevices folks.

The Black Book Official AuctionReport is sort of like a car blue bookfor shop machinery. This also listsbunches of auction houses likely toconduct electronic auctions.

A great cable and television stationtabloid tech mag is TV Technology.Among other stuff, it’s got lots of adsfor toaster support products. And asimilar pub for commercial radiostations is called Radio World.

For all the fundamentals of digitalintegrated circuits, be sure to checkinto my TTL Cookbook and CMOSCookbook. Autographed copies permy nearby Synergetics ad. And myNUTS10.PS on GEnie PSRT offers abrand new tutorial on PostScript forHardware Hackers.

Our new Synergetics Consultant’sNetwork is also now up and running.Do give me a call at (602) 428-4073 ifyou want to participate on this orneed any info on any other technicaltopic. Let’s hear from you.

Don Lancaster’s


Epoxy encapsulation mythsNichrome & resistance wireSemiconductor suppliers IIIFCC part 68 phone interfaceCopy protection absurdities

61.1

Fig. 1 – THE RESISTIVITY FOR ANY MATERIAL gets defined as theface-to-face electrical resistance of a unit cube. Here are several resistivityvalues for some of the more popular metals and alloys.

Aluminum 2.8 1.64Brass 7.0 4.07Constantan 44.1 25.60Copper 1.7 1.00

German Silver 33.0 19.18Gold 2.4 1.42Invar 81.0 47.00Iron 10.0 5.81

Lead 22.0 12.79Magnesium 4.6 2.67Molybdenum 5.7 3.31Music wire 11.8 6.86

Monel 42.0 24.40Nichrome 150.0 87.20Nickel 7.8 4.53Platinum 10.0 5.81Silver 1.6 0.95

Tantalum 15.5 9.01Tin 11.5 6.69Tungsten 5.5 3.20Zinc 5.7 3.34

MATERIALRESISTIVITYmeasured in

µΩ -cm

RESISTIVITYas compared

to copper

History often repeats itself.First as a tragedy and thenas a farce. It sure amazesme how many hardware

hackers and software types refuse tolearn from the past.

For instance, over a decade ago,the Apple II community conclusivelyproved beyond a shadow of a doubtthat copy protection does not work.

Never did and never will.Neither do the hardware dongles or

similar add-ons. Yet many IBM andPC compatible folks are hell-bent onwasting new time, dollars, and energyreproving this fundamental truth tothemselves. You will find only threeknown effects of copy protection: (A)It hacks off and inconveniences yourlegitimate users, sending them all tounlocked competitive products; (B) Itdiverts time and energy that is bestspent improving and updating yourcode; And, of course, (C) Any copyprotection dramatically increases thenumber of the bootleg copies of yourproduct that get circulated.

The reason for C is simple. Copyprotection always attracts attention toitself, causing scads of ultra-creativepeople to devote countless hours oftime and energy towards cracking thesecrets of your product.

Your bottom line is this: Undoingcopy protection is fun! Not only is itchallenging fun, it is by far the fastestand most cost effective way to learnmachine language programming. Andone of the best and the cheapest highquality learning experiences you willfind anywhere ever.

Not to mention offering positivelysuperb entertainment value.

On most hardware offerings, evengrinding a part number off the keyintegrated circuit will have the exactopposite of the intended effect: Allthis does is cause lots of high energypeople to puzzle out what the chip isand where to get one. The universalhacker popularity for that BA1404stereo FM broadcaster can be directlytraced to one firm stupidly grindingoff one too many part numbers.

By far the most absurd notion on

hardware copy protection to recentlyresurrect itself is to…

Pot it in epoxy!

I simply can’t believe the numberof calls and letters I’ve gotten on thislately. Back in the late 1950’s, it wasconclusively seen that potting yourcircuits in epoxy in no manner offersany design secrecy whatsoever. Infact, epoxy potting will always havethe exact opposite effect.

First, any reasonably good designengineer could select a "black box"approach and carefully look at theinputs and the outputs of the circuit.From the circuit’s size, cost, and frombeing aware of trade journals, databooks, distributor’s catalogs, and ap

notes, they can easily come up withthree or four methods to provide thesame function.

At least one of which will end upfar cheaper, better, and more creativethan yours.

Second, it’s a real trivial matter toX-ray any potted project. Free even,if it is a small module and you visit areasonably curious dentist.

Third, most of the epoxy sourcesalso supply epoxy strippers. Thesecheaply, rapidly, and convenientlydissolve out the potting compound, soit can be quickly washed away.

Fourth, epoxy could have severaldisruptive effects on your circuits. Itchanges the heat distribution and theoperating temperatures. It can subtly

61.2

Hardware Hacker

Fig. 2 – SOME TYPICAL RESISTANCE VALUES for different materials andwire gauges.

Aluminum 2 17 169 1720Brass 4 41 419 4260Constantan 26 260 2640 26,800Copper 1 10 103 1050

German Silver 19 194 1970 20,100Gold 1 14 141 1480Invar 47 477 4850 49,300Iron 6 59 598 6080

Lead 13 130 1320 13,400Magnesium 3 27 275 2800Molybdenum 3 34 341 3470Music wire 7 70 706 7180

Monel 24 247 2451 25,600Nichrome 65 659 6750 70,240Nickel 5 46 467 4750Platinum 6 59 598 6080Silver 1 10 98 991

Tantalum 9 91 928 9430Tin 7 68 688 7002Tungsten 3 32 330 3350Zinc 3 33 344 3450

MATERIAL10

gauge20

gauge30

gauge40

gauge

Values in milliohms per foot ~or~ Ohms per 1000 feet.

detune polystyrene capacitors. Itsweight shifts mechanical resonancesto more destructive frequencies.

Fifth, a very little known fact: Theferrite rf beads used on typical highfrequency analog circuits must beable to change their size slightly orthey will not work properly. The highfrequency energy gets absorbed by amagnetostriction that in turn convertsto heat. Locking ferrite beads in anepoxy can alter their response.

Used with care, there are times andplaces where the epoxy potting is anappropriate technique. Especially forwater resistance or use in hazardousenvironments. But epoxy potting forcopy protection just does not work.

Getting "Nichrome" wire

I’ve gotten several calls and lettersrecently wanting hacker sources for"Nichrome" wire. I’ll show you somesources and alternates in just a bit.

But please note that "Nichrome" isone particular brand of one particularformulation of what is more properlycalled resistance wire.

Most often, you’ll want all of yourelectrical or electronic wires to bevery efficient. And wasting as littleenergy and producing as little heat aspossible. But there are other timesand places when you want to cause awire to intentionally generate heat orcreate a specific voltage drop.

Obvious examples include toasters,electric blankets, hot wire plastic orfoam cutters, laminating machines,space heaters, soldering irons, motorstarters, thermal relays, refrigeratordefrosters, or for dummy transmitterloads. Some non-obvious places forcarefully controlled resistance in wireformat include current meter shuntsand sensors that turn your printer onwhenever you power your computer.

Most elements, alloys, and other

materials group themselves into fourtypes. Conductors can pass electricityfairly easily and have low resistances.Conductors can include both ordinarywire and resistance wire.

Semiconductors offer a moderatelyhigh resistance to electrical currents,with silicon and germanium being themost obvious examples. Insulatorsoffer very high resistance to electricalcurrent. Rubber, glass, plastics, andceramics are typical insulators.

And, finally, the Superconductorscan offer zero resistance to electricalcurrents. But all superconductors arerestricted to exotic formulations andspecial conditions under extremelylow temperatures. You’ll find moreon superconductors in the HardwareHacker II reprints.

Take a one centimeter cube of anyelement, alloy, or material. Next, youapply a voltage from full face to theopposite full face. Then measure thecurrent. By Ohm’s Law, the ratio ofthe voltage to current determines theresistance of the cube. But we have aspecial name for the resistance of aunit cube. This is the resistivity, andis shown by ρ, the Greek letter rho.

The resistance of a wire increaseswith its length and will decrease inproportion to its area. The metricresistivity units are Ohm-centimeters2

per centimeter, or Ohm-centimeters.I’ll use a wondrously oddball unit ofmicroOhm-centimeters (µΩ-cm) hereso our numbers look nicer.

Resistivity values let us comparematerials independent of their actualsizes. Some popular resistivity valuesare shown in figure one, while figuretwo shows you how much resistanceyou can expect for various wire sizesof selected materials.

The lowest resistivity of commonelements or alloys is silver, checkingin at 1.6 µΩ-cm. But silver is fairlyrare and readily tarnishes, and thecommodity price of silver changes allover the lot. So, silver isn’t used toomuch except for RFI suppression andexotic military stuff.

Copper, of course, is the universalbest choice in a conductor. It has aresistivity of a mere 1.7 µΩ-cm. Onlyfive percent worse than silver.

At first glance, aluminum appearsalmost as good as copper, having aconductivity only 64 percent worse.In theory, the thicker but cheaper and

61.3

March, 1993

Fig. 3 – THE CIRCUITWERKES MPC-2 is a FCC Part 68 telephone interfacethat offers a "pass through" type approval for your own hacker projects.

4

3

5

7

2

6

8

1

Ring detect output

Ring detect ground

Audio in/out

Audio in/out or ground

Line detect output

Line detect ground

Answer relay +12

Answer relay ground

jumper forunbalanced

ring

tip

H11AA1

H11AA1

600 , 1:1

RJ11phonejack

22K

1K

0.56 F

0.1 F

0.1 F

0.01 F

varis

tor

µ

µ

µ

µ

Ω

lighter aluminum conductors could besubstituted.

But aluminum has a pair of nastyhabits which include electrochemicaldecomposition and the building up ofsapphire hard (literally!) tough oxidecoatings. Making a solid connectionto an aluminum wire is not a trivialtask. Several decades ago, a bunch ofhouse trailers burned up after someabortive attempts at trying to perfectaluminum wiring.

Most of the other popular elementsand alloys have resistivities that aremoderately higher than copper. But amagic alloy of percent nickel,percent iron, and percent chromeprovides a resistivity over fifty timeshigher than copper. When combinedwith its other useful properties, this

alloy makes an outstandingresistance wire.

Figure two shows you how muchresistance to expect for various wiresizes for each of these materials. Afoot of gauge Nichrome wire has aresistance of ohms. The samealloy in gauge provides around

ohms total.Resistance wire gets measured in

ohms per thousand feet. Or you mayprefer its equivalent of milliohms perfoot. Naturally, resistance wire worksjust like any other resistor, obeyingOhm’s law and the usual…

P = E /R

power relations. A watt of electricityis, of course, a watt of heat. And aBTU of heat equals watts. Soyou can easily calculate the amountof heat you should generate. As areminder, a or

is the amount of heat needed toraise the temperature of one pound ofwater by one degree Farenheit.

Other resistance wire parametersdo include the tensile strength, thetemperature coefficient of resistance,and the temperature coefficient ofexpansion. The resistance tempcogets important fast in such things asmeter shunts. The expansion tempcobecomes crucial when you are goingthrough some ceramic seal. Shouldthe wire and the ceramic expand atdifferent rates, you can self destructat high temperatures.

The fastest and simplest way to getsome Nichrome wire to play with isto gently crush up a surplus power

resistor in a vise and unwind the wire.Different sizes offer different lengthsand gauges of wire. Resistance wireoften ends up available surplus atbargain prices, especially at

. also offers cheap resistance

wires. Originally used as refrigeratordefroster elements.

One big supplier of new resistancewire is . Theirequivalent to "Nichrome" is known as

. They also offer two dozenother variations. Theirprovides even higher resistivity withbetter tempcos for both resistance andexpansion. This alloy uses chrome,aluminum, and iron, with traces ofadded carbon and silicon. It is alsoslightly lighter in weight.

By the way, other trade names for are , ,

, , ,and .

For this month’s contest, just tellme about a new or unusual hacker usefor resistance wire. There’ll be all ofthe normal

book prizes, along with an

all expense paid Thatcher, for two going to the best

submission of all.As usual, send your written entries

to me here at and not to editorial.

In several past columns, we havelooked at the .These are required any time you wantto put voice, music, caller id data, ormodem tones on or off of the phoneline. The key component needed isjust a fancy transformer with a highisolation voltage rating, a very goodbalance, and the ability to accept dcprimary current.

There are lots of dollars, time, andeffort needed to get an interfacetype approved. And

. At leastin the .

Several firms now offer "pass thru"interfaces that you can include withinyour own circuits to get an instant

part 68 Interfaces

it is now illegalto make any connection to the phoneline without going through anapproved Part 68 interface

Nichrome

British ThermalUnit

FairRadio Sales American Science andSurplus

MWS Wire Industries

Nichrome Trophet C Alloy CHAI-NiCr60 Chromel C Nikrothal 6

Electroloy

Incredible Secret MoneyMachine II

tinaja quest

Synergetics

61

MWS-675MWS-875

2415

200.659

306.75

17.58

BTU

(FOB AZ)

FCC

FCC

US

Electronics Now

FCC

A hacker’s part 68telephone interface

2

61.4

Hardware Hacker

SEMICONDUCTOR RESOURCES, PART III

Teccor Electronics

Texas Instruments

Toshiba America

Unitrode Integrated Circuits

Western Design Center

Xicor

Zilog

Siemens Components

Sierra Semiconductor

Signetics

Silicon General

Siliconix

Sony Corporation

Standard Microsystems

Stanford Telecommunications

Tektronix

Teledyne Components

Teltone

Panasonic

Plessey Semiconductor

Raytheon Semiconductor

Rockwell International

ROHM Corporation

Samsung Semiconductor

Sanyo

SEEQ Technology

Seiko Instruments

SGS-Thomson

Sharp Electronics

OKI Semiconductor785 N Mary AvenueSunnyvale, CA 94086(800) 832-6654

1 Panasonic WaySecaucus, NJ 07094(201) 348-7000

PO Box 660017Scotts Valley, CA 95067(408) 438-2900

350 Ellis StreetMountain View, CA 94039(415) 968-9211

4311 Jamboree Road, box CNewport Beach, CA 92658(714) 833-4600

3034 Owen DriveAntioch, TN 37013(615) 641-2020

3725 North First StreetSan Jose, CA 95134(408) 435-5400

80 Commerce DriveAllendale, NJ 07401(201) 825-8080

47131 Bayside PkwyFremont, CA 94537(510) 226-7400

2990 West Lomita BlvdTorrance, CA 90505(310) 517-7770

1000 East Bell RoadPhoenix, AZ 85022(602) 867-6100

10 Sharp PlazaMahwah, NJ 07430(201) 529-8757

2191 Laurelwood RoadSanta Clara, CA 95054(408) 980-4568

2075 N Capitol AvenueSan Jose, CA 95132(408) 263-9300


11861 Western AvenueGarden Grove, CA 92641(714) 898-8121


10833 Valley View StreetCypress, CA 90630(714) 220-9100

80 Arkay DriveHauppauge, NY 11787(516) 273-3100

2421 Mission College BlvdSanta Clara, CA 95056(408) 748-1010

PO Box 500Beaverton, OR 97077(800) 835-9433

1300 Terra Bella AvenueMountain View, CA 94043(415) 968-9241

22121 20th Avenue SEBothel, WA 98021(800) 426-3926

1801 Hurd DriveIrving, TX 75038(214) 580-1515

PO Box 401560Dallas, TX 75240(800) 336-5236

9775 Toledo WayIrvine, CA 92718(714) 455-2000

7 Continental BlvdMerrimack, NH 03054(603) 424-2410

2166 East Brown RoadMesa, AZ 85213(602) 962-4545

1511 Buckeye DriveMilpitas, CA 95035(408) 432-8888

210 Hacienda AvenueCampbell, CA 95008(408) 370-8000

and automatic type approval. The twomajor suppliers are nowand . Sadly,their pricing has been too high formost hacker uses.

A startup outfit by the name of is now offering a new

and hacker friendly Part interfaceat a user acceptable price of .And yes, it offers a full type approvalpass thru. Subject only to a few easyrules that involve component spacing,labels, docs, and mods.

Figure three shows you the circuit.A small relay decides the

and the states. To "sieze" or"answer" the line, you apply voltsdc to the relay, providing mils.

The ring detector circuit is activeonly when on hook. This consists of aoptoisolator that responds to the highac ringing voltage, typically voltsat a frequency of to Hertz. Theoutput of the ring detector is an opencollector. You’ll have to provide bothan external pullup resistor and a filtercapacitor to ground. Suitable valuesare and microfarads.

The main data path is active bothon and off hook. This dual feature isneeded for a caller id compatibility.When you are on hook, the data pathis capacitor coupled.

When off hook, the data path getsdc coupled through the transformerprimary. A second optoisolator inparallel with the primary acts as aline current detector. The line currentgets detected by monitoring your dc

drop across the primary.The line current detection lets you

know when your calling party hangsup. This optoisolator also offers opencollector output. A pullup resistor isalso required here.

The main data path is just a specialtransformer with two clipping diodesto limit your maximum applied audio.A jumper option allows you to selecta balanced or single ended ohmsource/sink for your audio.

Typically, your computer will firstmonitor the ring detector. After aring, it siezes the line and optionallygrabs the caller id tones. Then it willsend or receive your voice or data.Finally, you can hang up by droppingout the relay. Either by detecting theabsence of line current or by hangingup on purpose.

As a second contest for this month,

CermetekDallas Semiconductor

CircuitWerkes

on-hookoff-hook

voltage

14040

68$29.95

1260

28

12 K 5

600

61.5

March, 1993

NAMES AND NUMBERS

American Science & Surplus

Lor’d Industries Limited

MWS Wire Industries

Nonlinear Nonsense

Printer’s Devil

Satellite Watch News

Scrambling News

SRS Encoder

Stanford Telecomm

Cermetek

CircuitWerkes

Dallas Semiconductor

Fair Radio Sales

GEnie

601 Linden PlaceEvanston, IL 60202(708) 475-8440

1308 Borregas AvenueSunnyvale, CA 94089(408) 752-5000

6212 Southwest 8th PlaceGainesville, FL 32607(904) 331-5999

4401 Beltwood Pkwy SouthDallas, TX 75244(214) 450-0400

PO Box 1105Lima, OH 45802(419) 227-6573

401 N Washington StreetRockville, MD 20850(800) 638-9636

Box 156Hancock, WI 54943(715) 249-5611

31200 Cedar Valley DriveWestlake Village, CA 91362(818) 991-8553

Route 1 Box 5140Morrisville, VT 05661(802) 888-5275

PO Box 66Harrison, ID 83833(208) 689-3738

6599 Commerce Court, #103Gainesville, VA 22065(703) 347-7926

1552 Hertel AvenueBuffalo, NY 14216(716) 874-2088

PO Box 30668Seattle, WA 98103(206) 362-5267 [E-mail]

2421 Mission College BlvdSanta Clara, CA 95054(408) 748-1010

just tell me about a new or unusualapplication for a hacker legal Partinterface project.

Much more info on those caller idapplications appears in a dozen fileson my .

We will wrap up our continuinglisting of the major semiconductorhouses in a third and final sidebar.

This month, we will cover upthrough . I’ve tried to zero in onthose suppliers of the greatest hackerinterest. Let me know if I missed anyof your favorites.

A complete list will appear in the reprints. I’ve

also gathered them together into the download you’ll find on.

As we have seen before, your bestbet here is to request a short formcatalog, the price list, and a literaturedirectory. Be absolutely sure to useprofessionally sounding phone callsor your own custom PostScript laserletterhead. A ball-point-pen on tabletpaper flat out won’t hack it. Muchmore on finding and using tech infoare in my newly revised

.

We have got some really excitingnew publications for this month. Thefirst is Dick Oliver’s new

, a free quarterly newsletteron fractal modeling, chaos science,artifical life, and creative graphics.His fractal design software is alsocommercially offered.

Also free on professional request isthe newfrom . This is adozen pages of ap-notes and usefulreferences, along with bunches ofdata sheets for their high-end digitalspread spectrum chips.

The has detailedinsider information on the current tvvideo scrambling and descramblingmethods. They also offer books fullof schematics, mods and related techinfo. A competing newsletter is the

.The is a new monthly

newsletter from the. Lots of regional info on great

surplus buys here.And Joe Singers is

a superb alternative publication onhome printing and presswork. "Apress in every home; a home in everypress." Quarterly at a bargain peryear sub price.

Finally, the New Age AlternativesDiscount Catalog is another resourcefor pseudoscience devices and info.Fascinating reading fer sure. This oneis offered by .

We’ve previously seen that and

are additonal pseudosciencesupply houses. It sould would beinteresting to put together a masterdirectory for all of these. Again, I feelthey make some absolutely incrediblereading. Some of the locals aroundhere actually believe in all this stuff.And, amazingly, it does seem to workfor them. Or so they claim.

For now, though, I’ll stick with my"Looks like a duck, quacks like aduck" filter. Boy, a whole flock of’em flew over that time.

Misquoting Sagan, extra-ordinary

claims always demand extra-ordinaryevidence. Most especially when anyknown physical laws are flagrantlyviolated. An independently testableand fully reproducible experiment isalways the key you should watch for.

A reminder here that I have gotreprints available for most of mycolumns. Both inpublished hard copy and on line at

. The titles now includemy , ,the ,

and the new .Check my nearby ad formore details.

As usual, I have gathered most ofthe mentioned resources together intoboth of our andthe

sidebars. Do be sure to look herefirst. Also as usual, you can get techhelp, consultant referrals, and lots ofoff-the-wall networking by callingmy tech helpline.


GEnie

OKIZilog

Hardware Hacker IV

GEnie

IncredibleSecret Money Machine II

NonlinearNonsense

Spread Spectrum HandbookStanford Telecomm

Scrambling News

Satellite Watch NewsSRS Encoder

Seattle RoboticsSociety

Printer’s Devil

Lor’d IndustriesHigh

Energy Enterprises BorderlandSciences

Book-on-demand

GEnieAsk the Guru Hardware HackerBlatant Opportunist LaserWriter

Secrets Resource BinSynergetics

Names and NumbersSemiconductor Manufacturer’s

III

68

PSRT

ICMFGRS.PSPSRT

3-D

$10

PSRT

New tech lit

More semiconductor resources

61.6

Hardware Hacker

Don Lancaster’s


Using cubic splinesSwitchmode resources

Electrorheological fluidsNational’s simple switcher

Non-ionizing radiation safety

62.1

Fig. 1 – CUBIC SPLINES are a useful and convient way of handling smoothand graceful curves by using a sparse data set. Here are several of thefundamentals you will need to start exploring these on your own.

(A) Here is a cubic spline shown in its …graph space

initialpoint

finalpoint

influencepoint #1 influence

point #2

The first influencepoint sets the direction

and enthuasiasm that thespline leaves the initial

point of the curve.

The second influencepoint sets the direction

and enthuasiasm that thespline enters the final

point of the curve.(

( )

( )( )

x ,y

x ,y

x ,yx ,y

0 0

3 3

1 12 2

(B) Here is how a cubic spline appears in its …

= + + +

= + + +

equation space

x t t t

y t t t

A B C D

E F G H

3 2

3 2

t (or time) alwaysgoes from zero at the

initial point to oneat the final point

(C) A faster "cube-free" form of the math…

= ((( ) + ) + ) +

= ((( ) + ) + ) +

equation space

x t t t

y t t t

A B C D

E F G H

(D) How to get from graph space to equation space…

= - + - = - + -

= - + = - +

= - = -

= =

A 3 3 E 3 3

B 3 6 3 F 3 6 3

C 3 3 G 3 3

D H

x x x x y y y y

x x x y y y

x x y y

x y

3 2 1 0 3 2 1 0

2 1 0 2 1 0

1 0 1 0

0 0

(E) How to get from equation space to graph space…

= =

= + = +

= + = +

= + + + = + + +

x y

x y

x y

x y

D H

D C/3 H G/3

D 2C/3 + B/3 Y 2G/3 + F/3

D C B A H G F E

0 0

1 1

2 2

3 3

(F) Some cubic spline tools available on …GEnie PSRT

#606 GNZOTRX2.GPS New TEX-like Guru Gonzo utilities

#605 BEZIER1.PS Distance from point to Bezier curve

#590 BEZIER.PS Bezier curve fast evaluation.

#588 FUZZYBEZ.PS Bezier curve from fuzzy data (!)

#530 SPHERE.PS PS spherical nonlinear mapper

#214 GURU68.TXT Bezier curvetracing fundamentals

#205 NUBANNER.FNT Fast & accurate parade banner freefont

#202 TWIXTBEZ.FNT Flagwaver freefont & Bezier ct utility

#161 SLEEZOID.PS Avuncular sleezoid utility

#190 BEZLNGTH.PS Bezier curve length utility

#077 MEOWWRRR.PS PostScript puss de resistance

Let’s start with some updatesto our earlier columns. Yetanother approach to theNavicube is a plain old low

cost mechanical gyro. Which is theroute that has chosen withtheir unique system. Theirentire gyro is the size of a film can. Ithas been designed from the ground upfor consumer apps.

Prototype costs, of course, are stilltotally outrageous. To me, spinningwheels do seem a hopelessly outdatedinterim solution at best. There’s nodoubt that micromachined silicon isultimately the only way to go.

The of a traditional gyro firmhas assured me that it was "absolutelyimpossible" to create a rate gyro.Well, there are flat out far too manyemerging applications that a

gyro replacement. The paradigm shifted, and the time is long past

due for stunning cost reductions here.The choice a traditional gyro hasis simple: Bring out this inevitableproduct by yourself.

Or else go down in flames.Here are two more Asian electronic

resources: There’s now anversion of this popular trade journal.The

has a toll-free number whichlists manufacturers, importers,and exporters. Some other assistanceis also available.

There are lots of times and placeswhere you would like a machine or acomputer to create a graceful curve.Perhaps with a mill, on anengineering graph, in a surfacemodeler, vinyl signcutter, or for anyother typography, plain or fancy.

I have recently been exploring areally great scheme to elegantly dealwith graceful curves. These are called

. They sometimes do getcalled curves, after the Frenchmathematician who explored them.

What do we ask of a curve drawingmethod? First and foremost, it shouldlook good. Second, we want it to belargely , working

$5

CEO

$5

$5

CEO

52,000

CAD/CAM3-D

GyrationGyroPoint

demand

has

Asia

Hong Kong Trade DevelopmentCouncil

cubic splinesBezier

device independent

EDN

Cubic splines

62.2

Hardware Hacker

Fig. 2 – THIS AVUNCULAR SLEEZOID is a just-for-fun example of how youcan stop anywhere along a cubic spline. Note how the "t" parameter changes "faster" along the "more bent" portions of the curve.

the exact same way for video screens,laser printers, typesetters, embroiderymachines, or whatever. All done fromthe ordinary textfile.

Third, we’ll want it to use, easily described by using only a

few size-independent values. Fourth,we’ll want to be able to splice simplesplines together into more complexcurves without serious glitches.

Fifth and finally, we want it to bereasonably fast and easy to compute.And easy to understand.

The simplest way to build a curveis the . Where you moveover a click and up one notch. Keeprepeating with different sized clicksand notches until you step yourselfalong the entire curve. You make theclicks and notches small enough for"smooth" results, but big enough thatyou don’t need a zillion of them.

Better yet, do your clicking andnotching at the same time, by using a

or method that’s able toapproximate your curve with straightline segments. This looks a lot betterthan the step method, but there arestill joint breaks. And an incredibleamount of detail work is needed.

A fancier approach is to use littlebroken pieces of parabolas. This isthe or

method. But lots of piecesare still needed, and the results flatout do not look all that great. Which

is one of many reasons that TrueTypefonts are inferior to PostScript fonts.More on this another time.

I feel the "best" method for simpleand graceful curves involves using a

technique.There are two ways of looking at

cubic splines, and you’ll have to useboth of them for full control. You canwork in your , where youare actually looking at the spline. Oryou can work in your ,where you can precisely control yourunderlying math.

Figure one first shows you a cubicspline in its graph space. Regardlessof its size, only points (or eightx-y data values) are needed to fullyspecify the spline…

The at , tellsyou where the spline .

The at , tellsyou where the spline .

The at , should set the and

with which yourcurve the initial point.

The at, should set the

and the that yourcurve the final point.

Other names for the enthusiasm arethe or the .

A line connecting the initial pointand first influence point defines theinitial direction used by thespline. The first tiny step along yourspline should head out in thisdirection. Similarly, a line connectingthe second influence point and thefinal point defines the finaldirection for your spline.

To build a cubic spline in the graphspace, you set your end points. Thenyou move the influence points aroundto stretch and squeeze the spline intoits intended shape. Typically, yourinfluence points are well away fromthe curve itself.

Just like any middle managementmagician, you will find limits to therabbits a single cubic spline can pullout of its hat. One spline can get youany straight line or smoothly curvedpath; some smooth curves having atmost one point (such as asinewave); some curves with a single

(or "point"); or certain curveshaving one single and simple loop inthem. All of which are both gracefuland sparsely defined.

For fancier stuff, you use severalsplines end-to-end. We’ll see more onthis shortly.

Figure one also shows you a cubicspline in its equation space. Insteadof relating to , you instead relatethem to a new . Youcould think of as . willrange precisely from to asyour spline smoothly moves from itsinitial point to its final point.

One interesting way to look at thecubic splines is to think of a box in ,, and space. Inside the box is a

three dimensional snake-like curve.Look in the end of the box and youwill see your spline. Look in theside, and you will see how varies as (or time) goes from to . Or look

down through the top to see howvaries, again as goes from to .

Note that and are independentof each other. Each gets separatelydefined in terms of . Knowing onedoes reveal you the other. Unlessyou find first. Do note that usuallydoes move uniformly along yourcurve. Instead tends to move fasteralong the "more bent" portions of thecurve. And moves slower along yourstraighter portions.

Bopping between the equation andgraph space is the key to controlling

0 1

0 1

samesparse

data

step method

vector stroke

quadratic spline second ordercurvefit

cubic spline

graph space

equation space

four

initial point x ystarts

final point x yends

first influence point xy

leaves

second influence pointx y

directionenthusiasm

directionenthusiasm

enters

tension velocity

tangent

always

tangent

inflection

cusp

x yboth parameter t

t time t alwayszero one

xy t

xyyt

yt

xtt

x y

tnot

t tnot

t

0 0

3 3

1

1

22

62.3

March, 1993

Fig. 3 – CURVETRACED CUBIC SPLINES are ideal for animation andcartoon characters, such as the "puss de resistance" shown here. Only aword processor is needed to create this quality artwork. No scanner is used.

your splines. Figure one also showsyou the simple ninth grade algebraneeded to get from those influencepoints to the math equations, and viceversa. For some strange reason, thissimple and obvious two-way math isvery hard to find.

Let’s repeat the basic cubic splineequations here…

goes from zero to oneas you go from the beginning to theend of your spline.

The obvious reason we call thesecubic splines is that your highestpower of involved is a third powercube. The cubic term has most of itseffect on the of your curve.The quartic (squared) term does mostof its useful work in the . Thelinear term sets the initial , andthe final value sets your . Bysuitably combining these four terms,a wide and useful variety of splinecurves can be generated.

But doesn’t cubing sometime takeforever on typical computers? Well,you can get sneaky and eliminate anyneed for raising anything to the thirdpower. Instead of calculating eachindividual coefficient, what you do isrearrange the original equations as…

Or, restating things in English, tofake cubing, take and multiply it by. Add . Multiply by again. Add .

Multiply by again. And, finally, add . Presto. A cubeless cube.Inside the machine or computer,

the actual details of getting from anycubic spline to a frame bitmap or thetool paths will vary. But, in general,all you will do is repetitively use thesimple algebra of figure one to decidewhere you go next. Consistent withyour available step resolution.

Although you might use any oldcomputer language to explore cubicsplines, I’ve found that the generalpurpose PostScript language is by farthe fastest, easiest, and most fun wayto play with Bezier curves. I’ve nowposted a group of Bezier and cubicspline exploration tools to my

. A few of these are also listed

for you in figure one.For instance, following a suitable

scaling and translation, here is howyou request the figure one spline inPostScript…

Note that only a few dozen bytesare needed to specify the spline,

This is sparse data used atits very best.

By the way, if you don’t yet havereal PostScript, we now do offer theshareware emulatoron . Which runs fake PostScripton nearly printer or on nearlycomputer screen. Yes, the full sourcecode is included.

Does a cubic spline have a length?Well, obviously. But only if you arenot a mathematician. Go through thelength math, and a big ugly squareroot of some fourth order polynomial(which is worse than it sounds)should leap out at you. After years of

careful asking, I have yet to findsimple and exact closed form solutionfor the length of a cubic spline.

Yet, knowing the length of a splinegets interesting for positioningtypography on a curved surface, to fitfuzzy data, for correcting or creatingdistortions, or for that just-for-fun

surface you willfind in figure two.

So, what I’ll do instead is chop upany cubic spline into a hundred or sopieces. You then assume each piece isa straight line, and add their lengthsup. Your answer is typically goodenough for most graphical uses. Anda mere hundred points usually givesyou better than one part per thousandfinal accuracy.

By the way, if you do know how toquickly and conveniently find me theexact length of a cubic spline, pleaselet me know. A free

for your trouble.Every math freak that I’ve talked toinsists this is impossible. They havealmost convinced me.

Things get interesting when you

= A + B + C + D = E + F + G + H

D

= (((A ) + B) ) + C) + D = (((E ) + F) ) + G) + H

AB C

D

PSRT

GHOSTSCRIPTPSRT

x t t ty t t t

Once again, t

t

final end

middleslopeoffset

x t t ty t t t

t tt

GEnie

2 3 moveto 3 7.5 7 7 8 4 curveto stroke

fullyregardless of its final size or deviceresolution!

any any

much

any

very

avuncular sleezoid

Incredible SecretMoney Machine II

3 2

3 2

Getting fancy

62.4

Hardware Hacker


PO Box 130Hornbrook, CA 96044(916) 475-3179

121 International BlvdCorpus Christi, TX 78406(512) 289-0403


120 San Gabriel DriveSunnyvale, CA 94086(408) 737-7600

Box 6430Orange, CA 92613(714) 974-0200

800 Roosevelt Road E408Glen Ellyn, IL 60137(708) 469-3373

120 S chaparral Court #200Anaheim, CA 92808(714) 283-1123

5005 E McDowell RoadPhoenix, AZ 85008(800) 521-6274


2472 Eastman Avenue #33-34Ventura, CA 93003(805) 658-0933

120 S Chaparral Court #200Anaheim, CA 92808(714) 283-1123

1000 East Bell RoadPhoenix, AZ 85022(602) 867-6100


PO Box 401560Dallas, TX 75240(800) 336-5236

7 Continental BlvdMerrimack, NH 03054(603) 424-2410

SWITCHMODE RESOURCES

Allegro/Sprague

Home Power

Lambda Semiconductors

Linear Technology

Maxim

Motion

Motion Control

Motion Techniques

Motorola

National Semiconductor

PCIM

Power Techniques

SGS-Thomson

Siliconix

Texas Instruments

Unitrode Integrated Circuits

splice cubic splines together. This ishow you build fancy typography andother complex shapes. Ideally, youwant to at least match your end pointsand your end point slopes. The rate ofchange of the curvature at each jointshould also be constant, but this getsnasty in a hurry.

Picking the points gets tricky. Tryto go too far with each spline and youlose accuracy. Don’t go far enough,and you need too many splines andthe splines may become very noisesensitive. Creating nervous results.

I’ve written a simpleroutine that’s now in my

book/disk combo. You throwsome endpoints and slopes at it, and itbuilds up all of your splines for you.Curvetracing is really great for highquality digitized signatures that needonly tiny file sizes.

Curve tracing is also superb foranimation. Figure three shows you

, our puss de

resistance. Curvetracing can give youprecise and sharp results.

Only a word processor is needed;there’s no scanning involved. I haveincluded a full curvetracing toolkit inmy .

Ideally, you sure would like to justthrow some fancy and noisy artworkat a cubic spline generator and have itautomatically pick how many splinesto use to produce the "best" possibleresults. This is not trivial, especiallywith noisy data.

You first have to decide how longeach spline is to be and where it is togo. Then, you’ll most often want to

all the intermediate splines,controlling both the entry angles andentry points. Or otherwise restrictingthem for continuity.

The "horses’ mouth" paper on allof this is

by Michael Plassand Maureen Stone (with a little helpby some guy named Warnock). This

did appear in the July pg. . And otherwise

known as the Proceedingsfor . The math here is unbearablyheavy and obtuse.

So, I decided to take this general"fancy but noisy data into connectedcubic splines" concept and have nowgenerated somewhat similar resultswith . Which willcreate the best smooth cubic splinethrough any noisy data while keepingyour choice of constraints. Only ninthgrade algebra is involved, and mostof that gets fully automated. Speed isaround five seconds per spline.

We will have several contests thismonth. To start off, either find me asimple Bezier length formula (lots ofluck!), or show me a new and unusualtask for cubic splines. Or curvetraceme something interesting.

There will be the usual book prizes,

along with an all-expense-paidThatcher, for twogoing to the very best of all.

Be sure to send your written entriesto me at , rather than to

editorial. Any codecan be directly uploaded to .

Do power lines cause cancer? Onerecent movie and a lot of my helplinecallers do seem quite concerned overthis. As with any controversy, yourfirst step is picking up accurate andunbiased data. And useful tools foryour own research.

Start off with. Found in

for December , p. .This is an unbiased summary. There’salso the

. This oneis both expensive and has an alarmisttone about it.

As usual, any ongoing scientificcontroversy can be followed via the

. And anynewer important papers are likely toappear in an

report.For instruments and components,

two sources include and. And ads for similar

products appear in that trade journal.

One little noted fact: While highvoltage power lines sound strong and

(FOBAZ)

#517 GONZO15A.PTL

1983229-239SIGGRAPH

1983

#588 FUZZYBEZ.PS

PSRT

11, 1992 1724-1725

curve tracingPostScript

Secrets

Meowwrrr Synergetics

constrain

Curvefitting with piecewiseparametric cubics

ComputerGraphics

IncredibleSecret Money Machine

tinaja quest

Synergetics

Polarized Debate:’s and Cancer Science

Microwave News: A Reporton Non-Ionizing Radiation

Dialog Information Service

Electric Power ResearchInstitute

F. W. BellWalker Scientific

ComplianceEngineering

EMF

Electronics Now

Non-ionizing radiation safety

62.5

March, 1993

Fig. 4 – THE SIMPLE SWITCHER series of chips from National let you buildan efficient switchmode regulator with only five parts. Heatsinking can oftenbe eliminated completely. Free kits are available on professional request.

1-V

I N2 -

OU

T3 -

GN

D4 -

FB

K5 -

OF

F

LM2575-5

1N5819Schottky

100Fd

330Fd

330Hy

7-60 voltsdc input

+5 vdc, 1 ampdc output

µµ

µ+ +

nasty, their field strengths, expressedin at sane distances, are

than your normal internalelectrical human cell potentials. Andoverwhelmingly by far your largestmagnetic field that you’ve ever beenexposed to is the earth itself.

My own feelings are that if therewere any major problems here, theywould have become obvious a longtime ago. There probably are someobservable effects, but they probablydo lie within acceptable risk bounds.And are reasonably avoidable.

On the other hand, rethinking somereally dumb stuff (such as buildingnew playgrounds under high voltagelines or sitting on a police radar) isprobably a good idea. And utilitiesstudiously avoiding any careful andunbiased research certainly is not.There is probably a hacker buck to bemade providing low cost monitoringinstruments. And possibly a sciencefair project or school paper in yourown surveys.

I do have a hunch this will prove tobe an example of billions of dollarsbeing blown on what will ultimatelyprove to be a monumentally largenon-problem. There are much moreurgent and far more important thingsto be doing with your time and effort.

The folkshave been offering free sample kits oftheir new series ofvoltage regulators. Figure four showsyou a typical circuit. Only five partsare needed to take a raw volts ofinput and provide a fixed volts ofoutput. Other chips in the series giveother values of fixed or adjustableoutput. In step-up, or step-down, orpolarity inverting circuits.

We’ve looked at these switchmoderegulators in previous columns and inthe reprints. Themajor advantage of any switchmoderegulator is in its potential efficiency.Stepping volts on down to voltswith a one amp linear regulator is atits best only percent efficient.

For each watt of load power, youhave to burn up an extra seven wattsinternally.

But a switching regulator can, intheory, be percent efficient. Andgetting above percent is very easyin the real world. Thus, you only burn

up around milliwatts internallyfor each watt of load power. Whichmeans less input power and less heatto get dumped. Heatsinks can oftenbe eliminated entirely.

Any switching regulator does justthat. It is a high speed switch that israpidly turned on and off at a chosenduty cycle. Your duty cycle sets theaverage current through the outputinductor, and thus your load current.A feedback loop adjusts how long theswitch is on. During times the switchis off, a continuesthe inductor’s current path.

In our volt input example, yourswitch is only on for one eighth of thetime. Thus your average input currentis only an eighth that of a comparablelinear regulator. The frequency usedis kilohertz.

Full details appear on the relateddata sheets and ap notes. There’s alsoa companion diskette that lets youoptimize all your external componentvalues. By the way, both the inductorand the freewheeling diode values arecritical and brands and values

be used. The circuit simply willnot work with an inductor having toohigh a dc resistance or one that endsup saturating at higher currents.

Similarly, ordinary silicon diodesare too slow and too inefficient.

For this month’s resource sidebar, Ihave gathered together a few of themore obvious places to go for moreinformation on these switching modetechniques. Not only for regulators,but also for motor controls and powerinverters. The listing is mostly a mixof semiconductor houses who provideswitchmode chips and a collection ofthe leading trade journals.

National’s simple switcher is nice,but your best switchmode resource is

, who have bunches of freebiesamples and evaluation boards of anincredibly wide selection of voltageregulators and converters. Lots of apnotes, too.

Let me know if I’ve missed anyoneimportant. There are scads of hackeropportunities here. Especially in thearea of clean, stable, and lower costpower inverters. I’ll try to have morecircuits in future columns.

New arefound in for Octoberon pages . These are fluidswhose apparent viscosity can changewith the applied voltage. Obvious apswould be clutches, on-demand,and robotic muscles. Plus, of course,

7-60+5

40 5

12.5

10085

150

40

50

30, 1992761-766

4WD-

volts-per-milmuch lower


simple switcher

Hardware Hacker

freewheeling diode

exactmust

Maxim

Electrorheological FluidsScience

National’s simple switcher

Switchmode resources

New tech lit

62.6

Hardware Hacker


593 Massachusetts AvenueBoxborough, MA 01719(508) 264-4208

P.O. Box 97046Redmond, WA 98052(800) 3-DATAIO

3460 Hillview AvenuePalo Alto, CA 94304(415) 858-2700

275 Washington StreetNewton, MA 02158(617) 964-3030



12930 Saratoga Avenue, Bldg CSaratoga, CA 95070(408) 255-3016

219 East 46th StreetNew York, NY 10017(212) 838-8688

POB 1799, Grand Central StationNew York, NY 10163(212) 517-2800



1333 H Street NWWashington, DC 20005(202) 326-6400

25 Willowdale AvenuePort Washington, NY 11050(516) 767-2500

9800 MetcalfOverland Park, KS 66212(913) 341-1300

Box 809Thatcher, AZ 85552(602) 428-4073

1600 Feehanville DriveMount Prospect, IL 60056(708) 803-6100

Rockdale StreetWorcester, MA 01606(800) 962-4638

NAMES AND NUMBERS

F W Bell

Compliance Engineering

Data I/O

Dialog

EDN Asia

Electric Power Research Inst

GEnie

Gyration

Hong Kong Trade Council

Microwave News


Philips

Science

Sound & Communications

Sound & Video Contractor

Synergetics

TDK

Walker Scientific

being a just-obscure-enough studentpaper topic.

From , their. It includes

magnetic field sensors, temperaturesensors, and proximity detectors. Andthrough , a similar shortform catalog on devices for infrared,humidity, current, surface potential,and even powder levels.

An enormous and free from

lists just about all the ’s,’s, ’s, and such.

Two trade journals of interest toany professional sound installers arethe and the

.A reminder that I stock just about

all of the important PostScript booksfrom all of the major authors. I have

even gathered together one each ofeverything into our PostScript

package. And much more oneverything PostScript appears on my

.I’ve just added a new way to write

fancy math equations in PostScriptthat includes some -like features.See for details. Or try

for an editable copy ofour figure one example.

Several helpline callers have askedfor more info on . As always,you can call for yourlocal connect info. Because there arenow thousands of nodes across thecountry, the chances are goodthat access will be only a localcall away. There are other low tollarrangements as well.

is not yet the largest of the

information utility, but it is widelyregarded as having the most and thebest in the way of superb technicaldownloads. At last count, there weresome files on line waiting foryour immediate use.

uses the "two tier" pricingstructure. For a basic rate of permonth, you pick up unlimited email,movie reviews, the airline schedules,dial-a-joke, stock market quotes andgreat heaping bunches more. For thevalue-added services, such asand most of the computer libraries,there is a per hour surcharge. On

, this usually translates to anaverage of twenty one cents or so perlibrary download.

RoundTables that youmight just find of interest are ,

, , , (desktoppublishing) and (home officeand small business). Most boardsoffer downloadable libraries, currentnews, and on-line conferences. Plusall of those usual message andquestion/answer exchanges.

Two tips: If you are downloading atutorial textfile, or a new PostScriptroutine that you are reasonably goodat troubleshooting, use ist ratherthan . Assuming, of course,that you have a decent modem andclean lines. Listing an uncompressedtextfile is faster and cheaper than

ing a compressed version.Naturally, (or its improvedoffspring) should still be used on anyfile that must be absolutely correct.

If you are based, check into the supervisor. This lets you call

up in the middle of the night, checkmail, read files, download libraries,and such. Much faster and far moreconveniently than typing by hand.

Yes, is working on a fewnew graphical interfaces. But theystill admittedly are ridiculously farbehind on these.

As usual, I’ve gathered much ofthe resources I’ve mentioned into the

and sidebars. Check here first

before calling our tech helpline.Speaking of which, you can get

tech help, consultant referrals, andoff-the-wall networking by callingme at . Uh, your bestcalling times are weekdays, MountainStandard Time.


Other

EPROMEEPROM PLD

GEnie PSRT

TEXGNZOTRX2.PS

HACK61.GPS

(800) 638-9636

PSRT

PC

130,000

$5

PSRT

$6

RADIOMAC IBM A2-PRO DTP

HOSB

BBS

(L)XMODEM

XMODEMXMODEM

(602) 428-4073

Philips SemiconductorSensors Data Handbook

TDK Sensors

Wall Chartof Programmable Devices DataI/O

Sound & CommunicationsSound & Video Contractor

WholeWorks

GEnie

veryGEnie

GEnie

GEnie

GEnie

Alladin

GEnie

Names and Numbers SwitchmodeResources

Don Lancaster’s

Hardware HackerApril, 1993

Video game repair videosPiezoelectric fundamentals

Understanding Curie PointsSimple home EDM machining

Stunning new ic opportunities

63.1

Fig. 1 – EXCITING NEW HACKER CHIPS from the latest Integrated CircuitSystems data book. These will take years to sort out.

GSP500 –

A VGA to NTSC video genlocking processor. Allows VGA and super VGAtext and graphic images to be displayed on standard NTSC televisions orrecorded on a VCR. Also genlocks and synchronizes external camcorder orVCR inputs.

ICS1399 –

A music synthesizer for high performance professional keyboardinstruments. Includes 25 voices and on-board real time digital filters anddigital-to-analog conversion. Synthesis is by way of table lookup, sovirtually any real or imagined instrument can be emulated.

ICS2101 –

A digitally controlled audio mixer that accepts five stereo input pairs andprovides one stereo output pair. Log attenuation at half a decibel per stepover a sixty decibel range. Optional panning mono mode. Intended foraudio cards in multi-media personal computers.

ICS2008 –

A SMPTE Time Code receiver and generator. Offers both the older LTClongitudinal time code and the newer CITC vertical interval codes. Thesecodes are often used in video editing and to synchronize multimediaevents. Supports NTSC, PAL and film rates.

ICS2010 –

A MIDI compatible SMPTE time code processor. Allows you to use standardvideo time codes to control and sequence any MIDI music environment.Supports MIDI quarter frame messages. Selective video overlay is availableas an option.

ICS1700 –

A "Quicksaver" controller for Nickel-Cadmium batteries. Does a full chargein twenty minutes. Uses a temperature sensing and rate of chargetermination to determine a fast yet safe charging rate. Ideal for notebookcomputers and portable video applications.

ICS1660 –

A telephone caller id chip that includes ring detection and calling partynumber extraction. When provided by the phone company, the caller idsignals appear between the first and second rings and are extracted byFSK modem techniques. Includes power down features.

Every once in a while, a newhacker opportunity comes bythat is absolutely stunning.An entire book crammed full

of them is an even rarer event.So, drop what you are doing right

now and run out and grab yourself acopy of the new and free IntegratedCircuit Systems data book.

These folks have just come outwith an unbelievably mind blowingassortment of exciting new high-endhacker integrated circuits. Figure onegives you a quick summary of someof their more interesting products.Included are VGA to NTSC genlocks,25 voice, CD quality synthesizers, 5channel digitally controlled mixers,and SMPTE to MIDI time code chips.

Compared to these wonderments,their new fast battery charging chipsand the unique new caller id devicesseem hardly worth mentioning!

Oops. A major boo-boo. Back inthe resistance wire story, I shuddasaid that 17.58 watts is a heating rateof one BTU per minute. Well overhalf of the "correction" letters I goton this were in themselves wrong.

Another good source for Nichromesubstitutes is Hoskins. Their brandname is Chromel, and they are verybig in alloys for higher temperatureheater elements.

Piezoelectricity

Piezo stuff seems really great forhacking. But a lot of you helplinecallers seem badly misinformed overwhat you can and cannot do piezo-wise. Let’s take a closer look…

As figure two shows us, certaindielectric (or insulating) materialsexhibit a piezoelectric effect. If youbend a piezo material, a charge canappear on its surface. Reversibly, ifyou apply an electrical charge to apiezo material, it should bend. Or atleast try to bend, creating a forceagainst whatever is restraining it.Thus, you can use a piezo material toconvert mechanical forces or motionsinto electrical signals. Or vice versa.

The oldest classic piezo material isquartz. Which can be sliced up and

plated for use in frequency standardcrystals, filters, accellerometers, timedelay lines, or force transducers.

A quartz crystal is just a rock. Ahighly mechanically resonant rockwhich has a few wires added to it.Depending on the application, thecrystal will electrically appear as avery low impedance series resonant

circuit. Or as a very high impedanceparallel resonant circuit. Positivefeedback externally applied aroundthe quartz crystal might cause it tooscillate at its resonant frequency orat a chosen overtone. The frequencycan end up very exact because of thetemperature stability and very high Qof the mechanical system involved.

63.2

Hardware Hacker

Fig. 2 – THE PIEZOELECTRIC EFFECT in certain dielectric materialsconverts an input voltage to a mechanical motion or vice versa. Importantuses include filters, beepers, sonar, ultrasonics, micropositioners, gyros,microphones, miniature fans, strain gauges, and furnace ignitors.

( + )

( - )

( 0 )

( 0 )

( + )

( - )

We’ll get further into crystals someother time. My favorite source for thelower frequency crystals is Statek,while Crystek is one of many placesto go for small quantities of customhigher frequencies.

If at all possible, there are only twocrystal frequencies which a hackershould select. These are the 32.768kilohertz used in digital clocks, or the3.579545 Megahertz used as the NTSC(Never the Same Color) subcarrierpilot. These two "magic" frequenciesare ridiculously cheaper and easier toget than any other choice. Even if youhave to divide or multiply to get whatyou really want, you’ll usually end upfar ahead by starting with these.

Another traditional piezo materialwas Rochelle Salt, otherwise knownas potassium sodium tartrate. Thismaterial got used in "crystal" phonocartridges and "crystal" microphones.But Rochelle Salt was not all thatstable or sensitive. You also had tochop up whole crystals, rather thanforming it in the precise shape youreally were after. Rochelle Salt has

largely been replaced by better andcheaper-to-process materials.

But you can buy Rochelle Salt atyour drugstore (it is also a laxative)and can easily grow your own piezomaterials. See Crystals and CrystalGrowing in the Doubleday ScienceSeries for more info.

One group of improved materialsinvolve the technical ceramics suchas barium titanate or the "PZT" leadzirconate titanate. These ceramics canbe molded into pretty near any shapebefore firing. The resonant structuressimilar to quartz crystals get used asfilters, especially for radio and tvintermediate frequency amplificationstages. Murata-Erie is one leadingsupplier here.

Fancier piezo resonant structurescan go by the name of surface wavedevices. By carefully controlling themetal patterns on a piezo surface, youcould launch and recover acousticalenergy. The patterns can give youprecise higher order filtering, timedelays, or an equalization response.One big advantage of SAW devices

are that they are pre-tuned and needno adjustments. The important usesinclude cable tv, television if filters,cellular phones, and microwave apps.Ads for these show up in MicrowavesNew Product Digest.

Larger flat piezo benders resonateat audio frequencies and can formbeepers or squawkers. You’ll find awide selection at Radio Shack, whilea leading volume supplier is ProjectsUnlimited. Note that a bender doesnot oscillate by itself. It has to getused for feedback in a transistor or alogic inverter circuit. Some bendershave taps provided to make theirfeedback easier. A pair of oscillatorscan get used to produce a series ofbeeps, instead of a continuous tone.

Physically smaller benders formultrasonic microphones. These wereonce applied for ultrasonic Dopplerburglar alarms before all those newpyroelectric "people detectors" blewthem out of the water. And for remotecontrols before infrared diodes didthem in. Ultrasonic mikes are stillused for the electronic measuringdevices used by contractors and ruginstallers. And to annoy dogs andmosquitoes. But, near as I can tell,though, all these really do is make themosquitoes hungry.

Piezo devices in sheet or strip formcould get used for hi-fi tweeters andhigher quality, low cost electret-style"condenser" microphones. Unlike thetraditional electrostatic mikes, nobias voltage supply is needed.

Larger size and higher power piezotransducers can be used for ultrasonicmachining, cleaning, and for thoseunderwater sonar aps. One source ofultrasonic cleaning transducers isBranson, while EDO Acoustics offerscustom higher power piezo devices.Surplus sonar devices are sometimesprovided by Fair Radio Sales. Oneleading sonar piezo manufacturer isInternational Transducer.

A sudden mechanical force appliedto a stack of piezo elements creates asparking barbeque lighter or a gasfurnace striker. You can check yourlocal hardware store for these.

A shorter and far more controlledstack makes a piezo micropositioner,a device that can precisely adjustthings those micron sized distancesrequired for microscopy, integratedcircuit manufacturing, or for DNA

63.3

April, 1993

Fig. 3 – JUST LIKE ANY OTHER CAPACITOR, a piezo device obeys an "aconly" response. The only time you will get any energy transfer betweenelectrical and mechanical inputs is when one or both are changing.

(A)Voltage

Input

(B)Mechanical

Motion

(C)ElectricalCurrent

(D)Net energy

Conversion?

YES

YES

YES

YES

YES

NO NO

research. Surprisingly high forces arenow available. One micropositionersource is NEC. Others advertise inthe Laser Focus World and Lasersand Optronics trade journals.

Piezo fans have gotten built byresonating a pair of mylar blades.These can be an interesting way ofhandling low power spot cooling, butare unlikely to put the smallest dentin the muffin fan market. The mainsupplier is Piezo Electric Products.While some interesting piezo steppersand motors have been offered, theseseem to be commercial failures.

Other emerging piezo uses includeaccellerometers, rate gyros, and forapps involving pressure transducers.

An exciting new variant of piezomaterial has now been developed byAtochem/Pennwalt. Ordinary Kynarplastic films are heated above theirCurie Point and have a strong electricfield applied. When cooled, this newelectric field will get locked in, thuscreating a piezo device known as anelectret.

You will now find zillions of newapplications for this thin, light, andultra low cost Kynar piezo material.Including infrared people detectors(the films can be both piezoelectricand pyroelectric), driveway trafficdetectors, bounceless pushbuttons,impact sensors, for electronic drums,shock detectors, handicapped aides,and bunches of others.

Those Atochem folks do have freesample piezo transducers availablefor you, along with instructions onhow to assemble microphones, flamedetectors, touch switches, and lots ofother hacker stuff with them. Usingnothing but business cards and foamcoffee cups. They also offer a seriesof piezo development kits.

Tech info on piezo stuff tends toget spread a little thin. I know of nopiezo industry trade journal, and theolder Piezoceramic Manufacturer’sAssociation appears to be long gone.There is a small Ultrasonic IndustryManufacturer’s Association.

Some piezo material appears in theIEEE Transactions on Sonics andUltrasonics. Also check the Journalof the Acoustical Society of America.And, of course, you can thoroughlyand cheaply research any technicaltopic through the Dialog InformationService.

The problems

As I see it, there are two serioushacker misconceptions over piezodevices that seem to be causing a lotof helpline grief. These are the factsthat most piezo devices must be keptcool, and that most piezo devices areac only and will not in any mannerrespond to continuous, steady state,or dc inputs.

Any piezo device has a criticaltemperature called the Curie Point.Above the Curie Point temperature,all piezo effects are lost. And staylost unless you go through a fancyand critical "recharging" process.

For most of the high volume, lowcost materials, the Curie Point liessomewhat above the temperature ofboiling water. You absolutely mustkeep both your ambient temperatureand any internal heat buildup aboveambient way under the Curie Pointtemperature at all times. For instance,using live steam near typical piezodevices is one big no-no. At least for

the current crop of materials.You must be extremely careful

when you solder a piezo device tomake certain you avoid reaching theCurie Point. Those ancient "crystal"phono cartridges were especiallysusceptable to soldering damage.

Yes, there are higher Curie Pointpiezo materials. But most of these areexpensive and out of the mainstream.Piezo Kinetics is one innovator here.

In general, though, any time thatyou try to "push the envelope" of anydevice capabilities, something has togive. The chances are very good thatraising your Curie Point will lead youto much higher materials cost, lowerconversion efficiencies, and somematching/coupling problems. All ofwhich will translate to more internalheat and poorer economics.

A piezo device is nothing but acapacitor that swaps charge back andforth. Figure three gives us a closerlook at what really happens here. Sayyou apply a positive voltage. Thedevice will bend when the voltage is

63.4

Hardware Hacker

PIEZO RESOURCES

Atochem/Pennwalt3 ParkwayPhiladelphia, PA 19102(215) 587-7000

AVX CorporationPO Box 867Myrtle Beach, SC 29577(803) 448-9411

Branson Ultrasonics41 Eagle RoadDanbury, CT 06813(203) 769-0400

Bruel & Kajer185 Forest StreetMarlborough, MA 01752(508) 481-7000

Channel Industries839 Ward DriveSanta Barbara, Ca 93111(805) 967-0171

Channel Products7100 Wilson Mills RoadChesterland, OH 44026(216) 423-0113

Crystek2371 Crystal DriveFort Myers, FL 33906(813) 936-2109

EDO Acoustics2645 South 300 WestSalt Lake City, UT 84115(801) 486-2115

Fair Radio SalesPO Box 1105Lima, OH 45802(419) 227-6573

Int’l Transducer Corp869 Ward DriveSanta Barbara, CA 93111(805) 683-2575

K-tech Corp901 Pennsylvania Ave, NEAlbuquerque, NM 87110(505) 268-3379

MG Electronics32 Ranick RoadHauppauge, NY 11788(516) 582-3400

Motorola Ceramic Products4800 Alameda blvd, NEAlbuquerque, NM 87113(505) 822-8801

Murata-Erie2200 Lake Park DriveSmyrna, GA 30080(404) 436-1300

NECPO Box 7241Mountain View, CA 94039(800) 632-3531

Piezo Electric Products212 Durham AvenueMetuchen, NJ 08840(908) 548-2800

Piezo KineticsPO Box 756Bellefonte, PA 16823(814) 355-1593

Projects Unlimited3680 Wyse RoadDayton, OH 45414(513) 890-1918

Shogyo287 Northern BlvdGreat Neck, NY 11021(516) 466-0911

Statek512 N Main StreetOrange, CA 92668(714) 639-7810

Ultrasonic Industry AssociationPO Box 5126Old Bridge, NJ 08857(201) 679-9666

Valpey-Fisher Corp75 South StreetHopkinton, MA 01748(508) 435-6831

applied and unbend afterward. Therewill be no current before the voltageis applied. There will be a positivecurrent only while your bending istaking place. The energy goes intothe physical motion work load andraising the internal charge state of thepiezo device. After your bending isfinished, you’ll still need to apply avoltage to keep the device bent, butthere will be zero current, either intoor out of the device.

When you remove the voltage, thedevice returns to its flat state. Thistime there should be a net negativecurrent out of the device as the higherinternal energy state gets released.Some of this negative energy may getspent overcoming any air resistance,producing internal heating, or doingother mechanical work.

At any rate, our key point here isthere is only a net energy flow into orout of a piezo device whenever the

applied voltage or your mechanicalforce is changing. The steady stateresponse is zero.

Just like any other capacitor.Now let’s look at it backward. Put

a "perfect" voltmeter on your piezodevice and push on the device. Whathappens? As soon as you press, thereis a net surface charge which yourvoltmeter measures. As long as youare pushing, the voltmeter will stillread the voltage resuting from thischarge. But, if there is any externalor internal resistive load at all, thecharge will rapidly drain off.

Use a "real" voltmeter instead, andyou will get a positive pulse whenyou first apply your pressure, and anegative pulse when you release it.Why? Because the resistance loadinside the voltmeter drains off theprevious charge.

Thus, piezo devices are inherentlyac devices that only respond when theforce, motion, or electrical signal ischanging. There is no "dc", "constantvoltage", or any "steady state" energyconversion response.

Many popular piezo devices have anatural time constant of one secondor so. They can be used at sub-audiofrequencies. But their dc steady stateresponse is zero. Piezo devices arethus largely unsuited for such thingsas weigh scales, nav accellerometers,position transducers, or pressure tovoltage converters. Unless you getreally sneaky and use fancy chopper,carrier, or integrator stunts.

Piezo Power Generation?

Several helpline callers have askedwhether piezo devices are suitable forcommercial power generation. Thepossibilities look very grim here. Byfar the highest power piezo electricitygenerator I know about is the lighterfor the carbide light on my cavinghelmet. Which is just a modified gasfurnace igniter. And while the smallwattage piezo fan motors do exist,they don’t exactly have the entire airconditioning industry quaking in theirboots.

Yes, there are higher power piezotransducers. Hundreds of watts forultrasonic cleaners and machining.And perhaps thousands of watts forsonar. But I know of none of theseever producing electricity.

In fact, I would be very surprised if

63.5

April, 1993

Fig. 4 – AN ULTRA-SIMPLE EDM LASHUP. The lamps act as dynamicregulators, with the smaller one setting your sparking rate Be certain to keepthe tool and workpiece insulated from ground at all times. A dielectric fluidmust be used. Kerosine is possible but not recommended.

110 vacpower

line

3 amp,400 volt

diode

40 wattlight bulb

200 wattlight bulb

both caps are200 µF, 200 v

To insulatedcutting tool

To insulatedcutting workpiece

WARNING: Extreme shock hazard!

+ +

there ever was any piezo device todate which generated more recoveredelectrical power than was used in itsconstruction.

Many new piezo aps seem stuckunder a two watt limit. Recent fans,positioners, and stepper motors abovethis size have been non-competitivewith traditional solutions.

Commercial power recovery wouldrequire devices hundreds or eventhousands of times larger than thetwo watt limit. Once again, wheneveryou push the envelope, something hasto got to give.

For piezo power generation, themechanical work input would have tobe oscillatory and usually has to beresonantly coupled. Ya gotta shakethe transducer, not simply push on it!Piezo devices also must be kept cool.If they get anywhere near their CuriePoint, all piezo effects stop.

Worse yet, the best efficiencies ofthe high power units are often fiftypercent or less. Leading to very badeconomics and internal heating.

Worst of all, most piezo elementsare inherently very high impedancedevices. Usually in the ten megohmrange. For maximum power transferout of any system, the impedances ofyour source and load must be madeequal. This means you’ll usually get ahigh voltage, higher frequency, highimpedance output from any piezodevice. Tens of kilovolts or higher forlarger devices. Efficiently convertingthis into recoverable power is not atrivial task.

Several of the ap notes drive homehow dramatically piezo output powerdrops if you try to drive too low aresistance load. From watts down tomilliwatts even.

It’s also not at all obvious to mehow you can efficiently and cheaplycombine the multiple outputs fromseveral piezo devices.

Finally, unless you are in an "Uh,compared to what?" situation in outerspace or on a desert island, the firstand foremost question in any powergeneration scheme is "What are theeconomics?" If the rate of the energyproduction cannot more than pay forthe time value of the money used inconstruction, then your conversionscheme is totally useless.

Infinite cost breakeven times aretrivially easy to pick up. All that has

to happen is that the interest on thetime value of the construction moneyexceed the value to date of thegenerated power.

Viable alternatives to piezo powergeneration are covered in depth inElectric Power Research Institute andthe Association of Energy Engineerspublications.

The bottom line: There are all sortsof incredible hardware hacking appswhich use piezoelectricity. Especiallywith all those new Kynar films. Butcommercial power generation doesnot seem to be one of them.

Piezo resources

I’ve gathered some of places to gofor more piezo info into our resourcesidebar. Most of the sources shownbut not covered above are suppliersof materials and devices.

For this month’s contest, either (A)tell me about a piezo trade journal,or (B) show me any new and hackerfriendly piezo ap that does not violatethe "no dc response" and "low temponly" rules. There will be all of myIncredible Secret Money Machine IIbook prizes, plus an all expense paidtinaja quest (FOB Thatcher, AZ) fortwo going to the very best of all.

As usual, send your entries directlyto me here at Synergetics and not toElectronics Now editorial.

More on EDM machining

Warning: What follows can involvesevere shock and fire hazards. Do nottry this trick at home unless you knowexactly what you are getting into!

But this one seems far too cute toignore. Awesome, even.

I’ve had a lot of helpline requestsfor more details on the EDM electricdischarge machining we looked attwo columns back. It turns out a verycheap, stunningly elegant, and ultrasimple scheme for EDM machiningfirst appeared in the March 1968 issueof Popular Science and later on gotreworked in the January 1991 issue ofHome Shop Machinist. Their circuitappears in figure four.

All you have is a half wave dcpower supply driving a relaxationoscillator, with the insulated toolbeing negative and the insulatedwork being positive. Any old threeamp, 400 volt power diode fromRadio Shack could get used as therectifier. Fresh and very high qualityelectrolytics are recommended. 200volts minimum. Older or very cheapones could possibly explode in thiscircuit. A "bomb shelter" type of caseis recommended.

The light bulbs have much lowerresistances when they are cold thanhot. These sneakily act as dynamic

63.6

Hardware Hacker

NAMES AND NUMBERS

Alpec55 Oak CourtDanville, CA 94526(510) 820-1763

Amusement BusinessBox 24970Nashville, TN 37202(615) 321-4250

Assoc Energy Engineers4025 Pleasantdale Rd, Ste 420Alanta, GA 30340(404) 447-5083

Carnivorous Plant NewsletterFullerton Arboretum, CSUFFullerton, CA 92634(714) 773-3579


Electric Power Research InstPO Box 10412Palo Alto, CA 94303(415) 855-2000

Elsworth Adhesives1610 North I-35, Ste 208Carrollton, TX 75006(214) 446-8000

Randy Fromm1944 Falmouth DriveEl Cajon, CA 92020(619) 593-6131


Hoskins10776 Hall RoadHamburg, MI 48139(313) 231-1900

Integrated Circuit SystemsPO Box 968Valley Forge, PA 19482(215) 666-1900

Journal Acoustical Society335 E 45th StreetNew York, NY 10017(212) 661-9404

MCM Electronics650 Congress Park DriveCenterville, OH 45459(800) 543-4330

SynergeticsBox 809Thatcher, AZ 85552(602) 428-4073

Teltone Corp22121 20th Avenue SEBothell, WA 98021(800) 426-3926

Unitrode7 Continental BlvdMerrimack, NH 03054(603) 424-2410

regulators to limit the current shouldyour tool get stuck. This is elegantsimplicity at its best. The size of thesmaller lamp sets your cutting rate.

Both the tool and the workpiecemust be fully and totally insulatedfrom ground! If you want to groundyour workpiece (a darn good idea), alarge isolation transformer must beadded to your ac input.

While you might employ plain oldkerosine as a dielectric cutting fluid,it is highly flammable. Not remotelyas nasty as gasoline, but very much afire hazard just the same. I wouldinstead recommend using the "real"water based dielectric resins we sawback in the EDM survey. You’ll havethe best luck with a drill press or amill that has a slow controllable ratevertical power feed.

The most obvious use is to removebroken taps or stuck drills. Be sure toremember that a continuous flow of

dielectric fluid between the tool andwork must be maintained at all times.

A reminder that EDM Today is theleading trade journal here, and yourforemost place to check for ads onmachines, materials, and supplies.

New tech lit

From Teltone, their new DesignSolutions data book on tone receivers,call progress detector ics, and phonesignalling devices. Along with somegood ap notes. From Unitrode, a newLinear Circuits Handbook. Mostly ondrivers, power supply circuits, andbattery charger chips.

Randy Fromm’s Big Blue Book ofReally Great Technical Informationtells you bunches about commercialvideo game repair. In a readable andwell organized format. Randy alsooffers videos on video monitors andon game repairs and refurbishment.

He has lots of insider tricks that

can quickly and cheaply solve typicalrepair problems.

I am amazed at how klutzy andprimitive many video games still are.Most of these are still foot squarecircuit boards crammed with jellybean TTL or CMOS chips. Thus, theyfail often but are easy to fix. I guessthat the desire to retrofit previousmachines has pretty much kept theolder technology in place.

Speaking of video games, MCMElectronics offers $8 bit drivers thatlet you remove the tamperproof Segaor Nintendo game cartridges.

If you are about to come unglued,check out Elsworth Adhesives. Theydo seem to stock just about all majorepoxies, hot melts, cyanoacrylates,silicones, and such from nearly all ofthe major suppliers.

The price of laser pointers is still infree fall. The cheapest this week isthe $72 model from Alpec. Range is55 yards or so.

Note that you can’t just connect avisible laser to a battery. Careful andtight current regulation is needed toprevent the fragile die from literallyblowing itself off its mounting.

Normally, an internal photodiodeis used in a feedback loop. I’ll try towork up more details on this in afuture column.

Our two unusual magazines for thismonth are Amusment Business andthe Carnivorous Plant Newsletter.

The former is where you go to rentthe Batmobile, buy a steam calliope,see how much your favorite rock staris making on their concerts, or findjob ads so you can run away and jointhe circus. The latter is for veggiesthat go chomp in the night.

A reminder here that I have gotautographed copies of my revisedIncredible Secret Money Machine IIhere for you at my own Synergetics.This book is a must if you are startingup your own tech venture. Plus areminders about my Hadware HackerRoundTable on GEnie PSRT at (800)638-9636. And our no charge voicetech hepline can be reached via (602)428-4073. Best calling times are 8-5weekdays, Mountain Standard time.

Most of those items I’ve mentioneddo appear in our Names & Numbersor Piezo Resources sidebars. Be sureto check here first before calling ourhelpline. Let’s hear from you.

Don Lancaster’s

Hardware HackerMay, 1993

Steam calliope sourcesMicropower oscillatorsAvoiding energy scamsThermodynamic basicsThe comm trade journals

64.1

Fig. 1 – A HEAT ENGINE accepts energy from a high temperature source,does useful mechanical work, and then will reject a portion of that energy to alower temperature sink. Only a fraction of the energy can be converted.

Heat source attemperature T

HEAT ENGINE

Heat sink attemperature T

H

L

Electronics cannot stand on itsown. It has to build upon allthe underlying foundations ofmath, physics, chemistry, and

the other engineering disciplines.This month, I figured I’d take a

back-to-the-basics tack over a topicthat has been causing more than itsshare of helpline grief lately.

In short, we are long past overduein taking a close look at the…

As our figure one shows us, a is some device or scheme that

accepts thermal energy at a high inputsource temperature , outputs someuseful mechanical work, and finallyrejects remaining thermal energy to alower output sink temperature .

Nearly all auto and airplane powersources use heat engines, as do mostelectrical generators. Variations onthe heat engine theme lead us to heatpumps, icemakers, vacuum systems,refrigerators, and compressors.

And, for that matter, to life itself.The study of heat engines is known

as . While more of amechanical engineering topic than anelectrical one, students have totake at least one thermo course;nearly all modern heat engines needlots of support electronics; manyhome power and new energy recoveryschemes are actually heat engines indisguise; and knowing the thermofundamentals lets you instantly sortout the perpetual motion ripoffs andthe outrageous pipe dreams from therealities of practical physics and realworld economics.

We should note up front that morepeople have spent more time hackingheat engine ideas than on otherengineering topic. The field has beenstudied to death, and there are ofreadily available literature out therewaiting for your immediate access.

Unless you can bring somethinggenuinely, truly, and astonishinglynew to the table, the chances are your"new" heat engine concept has gottenthoroughly trashed over decades ago.Or even centuries before.

Ferinstance, I got this model heatengine in the mail. It was a cleverdemo of how crucially important the

problem is in preventingyou from getting useful economics.Reversibility is a very sticky thermoproblem which was first solved in abrilliant breakthrough analysis firstdone by James Watt. In .

Any study of thermo starts off withthe laws of thermodynamics. Whileunproven, nobody has been ableto find exception to these laws.At least not on an everyday scale.

Countless individuals have blownincredible amounts of their time andmoney trying to crack these thermolaws. All of them have failed totally.

Without exception.The laws are pretty fundamental,

and range well beyond heat engines.For instance, cell biology, the verylife process itself, photosynthesis, thechemical reactions, and much of solarpower all must obey these laws.

Glibly parapharased, the laws are You cannot win; You cannot

break even: and Sure, the dice arecrooked, but this is the only game intown.

Uh, more formally: Left to its owndevices, heat energy always travelsfrom higher temperatures to lowerones. Systems always tend to their

most chaotic and lowest energy levelstates. Energy can neither be creatednor destroyed in any thermodynamicprocess.

If you do build a heat engine,

Ah yes, that fraction. How big andjust how much? Enter one of the mostbrilliant hardware hackers of all timeby the name of Sadi Carnot. As mosthardware hackers, Carnot did nothave the foggiest idea what he wasreally doing. It took "them" decadesto finally understand how utterlyprofound and fundamental Carnot’sdiscovery was.

Typical heat engines use a. More important heat engine

fluids include air, steam, ammonia,freon, mercury, nitrogen, hydrogen,helium, or even liquid sodium. Theworking fluid goes through a numberof individual steps or totrace out a . Obviously, a heatengine cycle must close upon itselfand return to initial conditions suchthat useful work can continue.

These thermodynamic cycles canusually be graphed in your choice ofa diagram or a

diagram.The inside the cycle on either

a p-v or t-s diagram is related to how

heatengine

thermodynamics

any

tons

reversibility

everany

onlya small fraction of the total energycan ever be recovered as useful work;all the rest is irretrievably lost as lowgrade heat.

workingfluid

processescycle

pressure-volume (p-v)temperature-entropy (t-s)

area

T

T

(A) EE(B)

(C)

(D)

1784

(A) (B)(C)

H

L

Fundamentals of thermodynamics

Thermo laws

64.2

Hardware Hacker

Fig. 2 – EFFICIENT HEAT ENGINES demand that all the processes used befully reversible. Here are some good and bad examples.

A

A

O

O

O

s one process in a heat engine cycle, assumeyou have a fluid you wish to compress by addingweight to the piston such that your piston dropsby exactly one foot…

n your first try, you throw an eight pound brickon the piston and note that the piston does in factdrop by one foot. You have done 8.0 foot poundsof work. As we will shortly see, this is a uselessand process, becauseone-half of your work will get lost as irrecoverablelow grade heat…

n your second try, you place a one pound rockon the piston, wait till things settle, and then addanother one pound rock. You will still need eightpounds of rocks, but this time, the work needed isonly 8/8 + 7/8 + 6/8 + 5/8 + 4/8 + 3/8 + 2/8 + 1/8= 4.5 foot pounds of work. This is a useful but

process in whichone-eighth of your work gets thrown away…

n your third try, you place a feather on thepiston, wait till things settle, and add anotherfeather. You still need eight pounds of feathers,but this time the work needed is only the tiniestamount above 4 foot pounds. This is a

process in which virtually noneof your work gets thrown away…

ny fully reversible scheme to compress or expand a fluid is alsocalled an process. Heat is neither added nor removedin any reversible adiabatic process.

MODERATELY IRREVERSIBLE

BADLY IRREVERSIBLE

FULLYREVERSIBLE

ADIABATIC

much useful work you can extractfrom your heat engine. Theof any engine is the ratio of the usefulwork you extract compared againstthe energy which you must dump aslow grade heat.

Numerous heat engine cycles havebeen dreamt up. The cycle getsused in gasoline engines, while the

cycle obviously gets used indiesel power plants. Electric powerturbines use a cycle. Or somemulti-stage improvement thereon. Alot of alternate energy people get realexcited over a cycle, since itis an "external combustion" type of

engine which can accept heat fromdiverse or low grade sources.

Every few years or so, somebodyreinvents the old Stirling engine, andthen builds a bunch of prototypes thatjust barely miss. Then they will justbarely go bankrupt. To date, the oldStirling cycle has largely proven to beboth a sucker bet and an economicrathole. Except possibly for arcanecryogenic cooling aps.

What Carnot did was ask "What isthe finest theoretical thermodynamiccycle you could possibly create?" and"What are the efficiency limits to thefinest possible cycle?"

It was obvious that each part of aCarnot cycle had to be lossless. Moreprecisely, all the processes involvedhad to be . You have to beable to undo anything you just didwithout losing any heat to friction orother losses. This means "no suddenmoves" and "no rapid changes", witheverything altering as incrementallyand as slowly as possible. It will alsomean zero friction, lossless seals, andperfect insulation.

Figure two shows you more on theconcept of reversibility.

Ferinstance, say you want to use apiston to compress the gas inside anon-insulated cylinder. Some work isneeded to get your gas reduced to arequired size. Any work above that islost as low grade heat.

Say you build up your cylinder andthrow an eight pound weight on it.

You note that this particular pistonhappens to drop by a foot, doing workto compress your gas. In this case,eight foot pounds of work were used,since the eight pound weight droppedby one foot.

Is this the best you can do? Sayinstead, you put a one pound weighton, waited till things settled down,added another one pound weight, andso on. You now have the first poundgoing a full foot and the final poundonly going an eighth of a foot. Yourtotal work is

foot pounds oftotal work input.

Yet, in each case, you compressedthe gas by the same amount, raisingits energy state by the same value.The extra foot pounds of work hasdropped through that irrecoverablelow grade heat rathole.

In both examples, you do have anirreversible process. But your secondone is clearly much better. As a thirdtry, put a feather on the piston. Waittill things settle, and then put anotherfeather on the piston. Repeat this foreight pounds of feathers, and you willalso end up with the gas compressedby a foot. And only foot poundsof total work will be needed. This is areversible process and the best youcan do. And twice as efficient as yourfirst attempt.

One more time: Ya gotta be able toundo what you just did. At all times,you do have to be willing and able tostuff the Genie into the bottle.

efficiency

Otto

Diesel

Rankin

Stirling

reversible

back

8/8 + 7/8 + 6/8 + 5/8 + 4/8+ 3/8 + 2/8 + 1/8 = 4.5

3.5

4.0

64.3

May, 1993

Fig. 3 – THE MOST EFFICIENT HEAT ENGINE you can possibly build iscalled a Carnot Cycle. All four processes are fully reversible. Even the bestCarnot cycles MUST dump a lot of irrecoverable energy as low grade heat.

adiabaticexpansion

isothermalcooling

adiabaticcompression

isothermalheating

VOLUME

PRESSURE

The inside the Carnot cycle determineshow much useful mechanical work is output.

The of a Carnot cycle is determinedsolely by this elegantly simple formula:

= (T - T ) / T = T / T

You can multiply this 0 -1 value by 100 to get thepercentage efficiency. Note that antemperature scale must be used such as Kelvin(Centigrade + 270) or Rankin (Farenheit + 460).

Note that the best possible efficiency of any heatengine depends upon the highside / lowsidetemperature differential and nothing else!

AREA

EFFICIENCY

ABSOLUTE

ONLY

η ∆H L H H

That’s what reversibility is all about.There are several rather important

reversible processes. One of these iscalled an process, whereeverything takes place at a constanttemperature. The heat energy receiverhas to be at a temperature only a tadlower than the energy source. And theheat source has to be so large thattaking a small amount of energy outof it does not significantly change itstemperature.

A second is an process,in which heat energy is neither addednor removed.

.At any rate, the Carnot cycle uses

fully reversible processes to trace outthe best possible of theoretically idealheat engine cycles.

Figure three shows you some moreCarnot cycle details. Once again, thisone is the best possible one you canever build. Why? Because of the fullreversibility. You just can’t get betterthan this. If you think otherwise, youare flat out wrong. Guaranteed.

In the Carnot cycle, you start witha working fluid at a low temperature.Then you adiabatically compress thatgas by doing work on it. Typically,the new external energy required cancome from a flywheel or a secondcylinder in the engine. Compressingthe fluid raises its temperature andreduces its volume.

. Thetemperature rise has to result solelyfrom the volume reduction itself.

Compression will continue until atemperature very slightly under thatof the heat source is reached.

After compression, an isothermalprocess transfers hot heat energy intothe fluid, expanding it and increasingthe pressure. The temperature, ofcourse, stays the same. In the thirdstep, your gas adiabatically expandswhile delivering useful output work.

The fluid volume goes up and thetemperature goes down.

A final isothermal process dumpsthe remaining heat energy to the lowend heat sink, reducing the volumeand closing the cycle.

Once again, that inside thecurve on the p-v diagram determineshow much work gets delivered.

Since every process is reversible,

you can input high temperature heatenergy to produce output mechanicalwork. Or, you can input mechanicalwork to pump heat from the low sideto the high side.

A gas engine runs "frontwards". Arefrigerator runs "backwards". And aheat pump can either heat or cool, byswapping the high side and low sidedestinations.

When you go through the math (thederivation takes a full lecture hour inany university physics course), thisstunningly elegant and simple resultpops out…

(T - T )/T

Restated in English:

.No matter what the cycle, fluid, or

the engineering used!And our key point: To get useful

work out of any heat engine, you’llhave to throw lots more energy away

as irrecoverable low grade heat.As an example, a modern auto

engine has a theoretical efficiency of percent, with something like

percent being a typical real worldvalue. That is at the flywheel. Theactual efficiency as a transportationsystem is far lower.

Oh yeah. One minor gotcha. Youhave to use absolute temperatures forthe Carnot formula to work. Absolutedegrees Rankin are degrees aboveFarenheit. Absolute degrees Kelvinare degrees above Centigrade.

And any percentage efficiency is ahundred times the efficiency stated asa fraction from to .

Let’s try out the formula ourselves.On down my street is an impressiveartesian hot well that’s spewing forthmightily at degrees F. Could weget some electricity out of it?

Assume the local average groundtemperature is degrees (The wellsits in the Upper Sonoran life zone.)Your best possible energy recoveryefficiency here would be…

isothermal

adiabatic

For a full reversibility,any compression or expansion of aworking fluid should be adiabatic

Extreme care isneeded to neither add nor remove anyheat energy during compression

area

The very bestpossible efficiency you could ever getout of any heat engine is determinedsolely by the ratio of your sourcetemperature to the sink temperature

=

55 38

460

273

0.0 1.0

125

75

H L Hη

64.4

Hardware Hacker

COMMUNICATION TRADE JOURNALS

8250 NW 27th Street, Ste 301Miami, FL 33122(305) 594-7735


6300 S Syracuse Way, Ste 650Englewood, CO 80111(303) 220-0600

2504 N Tamiami TrailNokomis, FL 34275(813) 966-9521

PO Box 3208Englewood, CO 80155(303) 792-0023

600 Community DriveManhasset, NY 11030(516) 562-5000

1221 Avenue of the AmericasNew York, NY 10020(212) 512-2000

6300 S Syracuse Way, Ste 650Englewood, CO 80111(303) 220-0600

One Technology Park DriveWestford, MA 01886(508) 692-0700


600 Community DriveManhasset, NY 11030(516) 562-5000

777 E Speer BlvdDenver, CO 80203(303) 832-6000

610 Washington StreetDedham, MA 02026(617) 326-8222 FAX

12 West 21 StreetNew York, NY 10010(212) 691-8215

All in Communications

Cellular Business

Communications

Communications News

Communications Technology

CommunicationsWeek

Data Communications

Global Communications

Lightwave

Mobile Radio Technology

Network Computing

RCR Wireless Communications

Telecommunications

Teleconnect

Fig. 4 – MICROPOWER CRYSTAL OSCILLATOR by Harris Semiconductoronly needs five microamps of supply current from a source as low as twovolts. It costs under a dollar. Free sample kits are available.

5

1 2 3 4

8 7 6

+V XT1 XT2 GND

EN F2 F1 OUT

32.768 kHz

+2 to +7 vdcoutputsquarewave

HA7210

Or a mere percent, under idealconditions. That’s assuming a perfectCarnot cycle. In the real world, you’dbe lucky to get a tiny fraction of that.Say three percent net. Thus, for everykilowatt hour you generate, you haveto throw of them away!

Sadly, it does make perfectly goodsense to ignore some worthof electricity a year just by dumping

it into the Gila River. Why? Becauseany real-world recovery project ofthis size and temperature differentialcould pay for the engineering,materials, operating costs, flood zonerisks, and the time value of moneyneeded to properly do the job.

Is there any way you can beat thethermo laws? Generating electricitywon’t hack it, since you can alwaysuse your electricity to run a motor,which instantly gets you back to aheat engine.

You can switch to a or evena cycle which uses multiplestages and different fluids. But theseoften will only marginally improvethe efficiency while doubling costs.

The only other way I know of is todo something useful with the rejectedlow grade heat. Say by heating water,equalizing process temperatures, orstarting your own catfish farm.

A solar panel that also heats watershould have much better economicsthan one that solely generates someelectricity. Schemes such as these aresometimes called andthey are now a very hot topic indeed.There is even atrade journal.

So, how do you separate the "real"heat engines from the scams and thewishful thinking daydreams? First,calculate your Carnot efficiency andsee what this reveals about the claimsinvolved. Be especially suspect of"this is not a heat engine," or "thethermodynamic laws do not apply tome" evasions.

Then carefully look at the ordiagrams (these will be veryobvious on any legit device). Thencheck carefully for anything which isobviously non-reversible.

Any sudden changes or purposelyadding coolant to close a cycle aredead giveaways that all is not well.

Always ask "Can each and everyprocess step in use be run backwardsjust as well as forwards?"

Then you throw in some economicanalysis. Most crucially your time tobreakeven. This is the length of timewhich is needed for your generatedpower to pay for the materials, thedesign, and time value of the moneyneeded to create the device. Assumethat watts is a heating rate ofone per minute, and raises onepound of water by one degree F. Andthat a nickel per kilowatt-hour is aworkable ballpark avoided cost forelectricity. And that a gallon of water weighs eight pounds. And that thetime value of money normally triplesthe cost of a project.

Note that the time to breakeven caneasily be infinite! If you produce lesselectrical revenue per year than theinterest on the construction financingis costing you, the longer you run, the

thirty-two

never

binarytrinary

cogeneration

World Cogeneration

p-v t-salways

((125 + 460) - (75 + 460))/(125 + 460) = .085

8.5

$20,000

17.58BTU

A reality check

64.5

May, 1993

NAMES AND NUMBERS




PO Box 1114Grass Valley, CA 95945(916) 478-3000

1301 Woody Burke Rd CB 1-25Melbourne, FL 32902(407) 724-3739

2000 Sierra Point ParkwayBrisbane, CA 94005(415) 589-8300


2775 S Quincy Street, Ste 610Arlington, VA 22206(800) NAV-0885

1250 S Grove Avenue, Ste 302Barrington, IL 60010(708) 382-2450

4218 JessupCeres, CA 95307(209) 668-0366

PO Box 11250Overland Park, KS 66207(913) 649-0567

14351 Myford RoadTustin, CA 92680(714) 573-6000

400 Commonwealth DriveWarrendale, PA 15096(412) 776-4841

Box 809Thatcher, AZ 85552(602) 428-4073

RFD #1 Keeler LaneNorth Salem, NY 10560(914) 669-5421

205 Ravendale DriveMountain View, CA 94043(415) 691-9211

100 Shepard StreetLawrence, MA 01843(508) 685-2557

PO Box 1589Dallas, TX 75221(214) 691-3911

Dialog

Electric Power Research Inst.

GEnie

Grass Valley Group

Harris Semiconductor

Hitachi

Industrial Laser Review

Navtech Books & Software

Power Engineering

Ragtime

Resource Central

Silicon Systems

Society Automotive Engineers

Synergetics

Rolf K. Taylor

Trident Microsystems

Voltek

World Cogeneration

more you will lose.Finally, be extremely wary of the

word "Stirling". When and where ithappens to occur.

My favorite popular thermo bookis by Sanford and foundin the Doubleday Science Series.

Beyond this one, pick up any of thedozens of college level course texts.Important thermo resources includethe from the

, and the from the

.Of the many trade journals,

is typical; it targets largescale electrical generation. And, ofcourse, virtually any and all thermopapers ever published are instantlyavailable through .

Where can you go to get a crystalfor a pager? Or to find out more onfiber optic comm? Or information onwireless modems? Or phone testing?Or computer local area networks?

As always, your first and foremostsource of insider information in anyfield is in the trade journals.

As our resource sidebar for thismonth, I have gathered together abunch of the more obscure and morefragmented communications tradejournals for you.

I have a hunch I may have missed afew here, so be sure to let me know ifyou have any other favorites. A free

for your trouble.

Hacking a crystal oscillator is nobig deal these days. You just bias anyold gate into its active regionand hang a crystal in the feedbackpath. But things get tricky fast if youtry to run at ultra low supply currentsor want to reliably start at unusuallylow voltages.

Most hackers have discovered thatyour typical grunt transistorsrun out of gain at ultra low currents.And ultimately found out that the bestroute to micropower oscillators wasto use bipolar transistors instead of

gates. has newly

introduced a cheap and very simple all- crystal oscillator

chip. It costs under a dollar and freesamples are available. As figure four

shows us, you simply hang a crystalon the chip, and away you go. Thecurrent is a mere five microamps at

kilohertz.Pin six is an enable. Keep it high to

run. Make it low to disable the chip.Pins seven and eight can program theoperating current. Make them bothhigh for low frequenciesand both low for high frequencies

. Supply voltage range is to volts.

Some new integrated circuits forthis month: The is a newengine interface peripheral offered by

. It receives gasolineengine crank and cam inputs for useas timing and pollution management.

From , a newvideo processing chip set that offersscalable, full motion video windows

and frame capture to systems.From , the new

picture-in-picture controller chip alsointended for video insertion aps.

The has a finevideonewly available.

A good bookstore for navigationtexts and satellite secrets is the

.One source for Apple II repairs and

supplies is .The best Apple II magazine is still

. And theRoundTable has just seen its thlibrary upload.

Yet another trade journal for thismonth is the .

Free samples of , ,and foams are available from

. Ask for their specifier kit.A good source for steam calliopes

is . They offer a catalog.

Heat Engines

SAE Library Society ofAutomotive Engineers EPRIPublications Electric PowerResearch Institute

PowerEngineering

Dialog

Harris SemiconductorSilicon Systems

Trident Video View

Hitachi

Grass Valley GroupDictionary of Technical Terms

Navitech Book & Software Store

Rolf Taylor

Resource Central A2 GEnie

Industrial Laser ReviewVolara Volextra

MinicelVoltek

Ragtime

ISMM II

CMOS

CMOS

CMOS

HA7210 CMOS

32

(10-100 kHz)

(5-10 MHz)2.0 7.0

SSI 67F687

VGAHD49049FS

GPS

20,000

$5

Communications resources

A micropower crystal oscillator

New tech lit

64.6

Hardware Hacker

Don Lancaster’s

Hardware HackerJune, 1993

Short haul telemetryMax-min slope theorySETI books & resourcesUnique new optical linkMaximum power transfers

65.1

Fig. 1 – THE MAXIMUM POWER TRANSFORM THEOREM tells us that youdeliver the most possible power to a load only when you purposely burn uphalf of the generated power in your source. Here are some key details.

(A) Typical generator and normalized load. Varying load resistor R changes the total delivered power…

(source)

(load)R1Ω

(B) Maximum power transfer takes place whenever the source resistance matches the load resistance…

1.0

0.5

0

POWER

0 1 2 3LOAD RESISTANCE IN OHMS

100%

50%

0%

EFFICIENCY

efficiency

load powersource power

(C) How to prove the maximum power transfer theorem…

Borrow these two rules from differential calculus…

d(uv) = vdu + udv

d(u du) = nun n-1du

The voltage across the load will be…

VL = R/(1 + R)

The load power E2/R will simplify to…

PL = R/(1 + R)2

Take the derivative and set it equal to zero…

(1 + R)-2- 2(1 + R)-3 = 0

And simplify to…

(1 + R) - 2 = 0

Which solves as R = 1.

As I might have mentioned atime or two before, I am thesysop of GEnie PSRT and dohave bunches of reprints of

my Hardware Hacker, Ask the Guru,Blatant Opportunist, Resource Binand LaserWriter Corner columns.

And hundreds of files on hacking,PostScript, and my Book-on-demandpublishing. Typical file downloadingcosts are around twenty one cents.

I’ve just made an arrangement withGEnie to provide you with a new fastmodem access startup. Just autodial(800) 638-8369 and then type HHH.When prompted, enter your top secretaccess code of XTX99005,SCRIPT.

Whatever you do, keep this secretpassword carefully hidden and do notreveal it to anyone else.

GEnie has many thousands of localaccess lines across the country. But ifyou live in a really remote area, theynow offer a brand new (800) numberservice. They’ve also improved theirMac graphic interface.

We might start off with a pair ofback-to-the-basics fundamentals…

Maximum power transfer

Say you’re using an electrical orelectronic generator. Say further ithappens to provide a one ohm sourceimpedance and is outputting a onevolt signal. What is your "best" loadresistance?

As figure one shows us, there is no"best" choice. Only compromises thatdepend entirely on exactly what youare trying to do.

If you make your load resistancefairly high, you’ll get high efficiencyand good regulation. But you will beunable to get the maximum possiblepower from your generator. Your acpower utility is an example where thegenerator impedance is made as lowas possible to minimize all the sourceand transmission losses.

If you make your load resistanceequal to your source resistance, youshould extract the maximum possiblepower from your generator. But theefficiency will be a mere fifty percentand your regulation will be poor.

Video and rf transmission lines getimportant areas where you want toprecisely match load to the source.Besides delivering maximum power,you’ll also minimize reflections andstanding waves. Other areas where"make load = source" are important

are the older power audio amplifiersdriving speakers, car batteries whencold cranking, and solar cells tryingto deliver as much power to the loadas possible.

You also have the choice of using avery low load resistance. Which will

65.2

Hardware Hacker

Fig. 2 – MAX-MIN THEORY is a branch of differential calculus that lets youquickly and easily find a maximum or a minimum of any reasonable curve.

At a local MAXIMUM, the slope (or thefirst derivative) will be ZERO and therate-of-change of slope (or the secondderivative) will be NEGATIVE…

At a local MINIMUM, the slope (or thefirst derivative) will be ZERO and therate-of-change of slope (or the secondderivative) will now be POSITIVE…

At an INFLECTION POINT, the slope(or the first derivative) will be ZEROand the rate-of-change of slope (or thesecond derivative) will also be ZERO…

give you a horrible efficiency and aterrible regulation. It also will onlydeliver a tiny fraction of the possiblegenerator power. But there are a veryfew lower level uses where you wantyour generator to look and act like acurrent source.

For instance, a current source loadfor a transistor amplifier can offer anenormously high voltage gain. Theseunusual apps sometimes justify thelow power and bad efficiency.

Do note what this maximum powertransfer curve is telling us: You candeliver the most power to a load bythrowing half of the generated poweraway in your source!

The max power transfer curve issurprisingly broad. Double or halveyour load and your power that getsdelivered only drops by about twelvepercent or so. Thus, an exact matchsometimes isn’t all that important formaximum power transfer. A precisematch just might be needed for otherreasons, though. Such as to eliminatestanding waves and reflections.

If you are going to mismatch, itusually pays to do so on the high side.This way your overall efficiency willbe better, even if the delivered powerdrops a tad.

Let’s look at several examples ofhow a bad source-to-load mismatchcan severely do you in. In figure two,let’s take a piezo striker and see what we can get out of it. Let’s assume thestriker has a source impedance of tenmegohms and outputs a peak of 1600volts. We will also disable the spark

gap to prevent breakdown.Into an open circuit, we get zero

power. For maximum possible power,we’ll use a ten meg load, matchingsource to load. Half the voltage willappear across the load, and our powerwill end up as 640 milliwatts. Per theusual P = E2/ R rule.

Which is over half a watt, so weshould be able to light a lamp with it,right? Wrong. As 2-B shows us, aflashlight bulb offers a resistance ofabout ten ohms. With a ten ohm loadand a ten meg source, you can onlydeliver 256 nanowatts!

Your efficiency is essentially zero.Ergo, no light.

Can you do better? Substituting aneon lamp for a flashlight bulb wouldhelp bunches. Instead, you can placea transformer with a 1000:1 turnsratio between the striker and the bulb,as shown in 2-C. A 1000:1 turns ratiogives you a 1,000,000:1 impedanceratio. Your bulb now "looks" like aten meg load to the source. And youshould get nearly the full maximumpower flashing the lamp.

Remember, of course, that all piezodevices are ac only generators.

Most small impedance mismatchesbetween source and load are not thatbig a deal. But bad ones (especiallywith high value sources driving lowvalue loads) will severely do you in.

Several columns back, we foundseveral good reasons why any piezopower production hacks were likelyto end up a bad scene. Some of youhelpline callers pointed out there is

an even more fundamental gotcha.Most power generators are either

E-field machines or H-field machines.An H-field machine uses a changingmagnetic field to induce current intoa conductor. An E-field machine willuse a changing electric field to inducea voltage across an insulator.

All E-field machines are inherentlyhigh impedance devices. The powerdensity of all known E-field machinesis extremely low. E-field machinestend to force you to the inefficientextreme left of the maximum powertransfer curve of figure one. Preciselywhere you don’t wanna be.

The curent state of the art in bothmaterials science and high vacuumtechniques simply will not allow us toconstruct any economical high powerE-field machine.

As far as I know, there never hasbeen any E-field machine anywhereever produce commercial "nickel perkilowatt-hour" ac power. I’ll give youan Incredible Secret Money Machineif you can prove me wrong on this.

And while any piezo generator isobviously an E-field machine, it isonly a "fair to middlin" one at its verybest. Sigh…

Finding maximumsand minimums

There’s a number of fairly obviousways you could verify that maximumpower transfer curve of figure one.Being lazy, I just told the incrediblysuperb general purpose PostScriptcomputer language to plot it for me.The short and simple figure one codeappears in HACK65.PS on my GEniePSRT RoundTable. As we have seenbefore, PostScript is now the ultimatehacker’s language.

Or, you could go into the lab anduse a wattmeter and a variable loadresistor. Which should give you thesame curve, again with its maximumvalue matching your source.

Let’s try using some math instead.There’s this ugly rumor going aroundthat electrical circuits will obey mathrules. And that you can predict whatthey will do simply by looking at theunderlying math.

In the figure one circuit, we have avoltage divider which attenuates ourone volt input by…

eout = R/(1 + R)

65.3

June, 1993

Fig. 3 – GROSSLY MISMATCHING your source and load impedances canseverely reduce your total available delivered power. Here are examples thattry to use a piezo striker as a power generator.

With an , 1600 volts isrouted to an infinite resistor. The totaldelivered load power is .

With an , 800 volts isdelivered to a 10 meg resistor. Totaldelivered power is a fairly respectable

.

With a ,1.6 millivolts is delivered to a 10 Ohmincandescent lamp. The total deliveredpower is a useless .

With a , nearly can be delivered to the

incandescent lamp by using a 1000:1turns ratio matching transformer.

With an , 0 volts getsent to an 0 Ohm resistor. The totaldelivered power will be .

OPEN CIRCUIT

ZERO

MATCHED LOAD

640 MILLIWATTS

BADLY MISMATCHED LOAD

256 NANOWATTS

MATCHED LOAD 640MILLIWATTS

SHORT CIRCUIT

ZERO

Your output power should be thisvoltage squared divided by the loadresistance. Which simplifies to…

Pout = R/(1 + R)2

You or a computer can then plotthis curve for different values of R togenerate the max power curve.

By the way, this stunt of using onevolt generators with one ohm sourceimpedances is called normalization.If you can ever analyze somethingusing easy numbers instead of hardones, it will usually pay to do so.Anything that can be scaled can alsobe normalized. Much more on this inmy Active Filter Cookbook.

But there is a much better way tofind your maximum power transferpoint. There is a math process calledmax-min theory that easily lets youfind maximum or minimum points forany reasonable curve. Figure threeshows you the key secret.

Any reasonable curve will alsohave a slope. A slope is simply the"steepness" or the "rise over run" ofany tiny portion of the curve. Onecrude way to find the slope of anypoint on a curve is to take a point justbefore and one just beyond and createa tiny triangle out of it. The rise/run(or tangent) of the triangle will equalthe slope of your curve.

As figure three shows us, there areonly three possible cases where youcan get a zero slope on a curve. Thesehappen only at a local maximum, at alocal minimum or, more rarely, at aninflection point. And that’s all thereis to max-min theory.

Just find the math expression forthe slope of your curve. Set it to zeroand solve it. All solutions will be amax, a min, or an inflection point.

How can you tell which is which?Often, it will be completely obvious.If not, you’ll go one step further andfind the slope of the slope. If you areat a local maximum (3A), the rate ofchange of slope will be negative. At aminimum, (3B), the rate of change ofslope will be positive. And if you arenow at an inflection point, the rate ofchange of slope will be zero.

Your "correct" and "exact" way todetermine the slope for any curve isknown as finding the derivative andthis whole field is called differentialcalculus. You could find a full set of

rules in any university level Calculus101 text. A good listing also appearsin the Mathematical Tables from theHandbook of Chemistry and Physics.

I’ve shown how you use max-mintheory to prove the maximum powertransfer theorem in figure one. Sureenough, the maximum is exactly at aload impedance which matches thesource. Taking most derivatives isquite simple. For instance, a parabola y = x2 has a slope anywhere of 2x.Good old un du and friends.

Advanced math can be neat stuff.And very valuable, too.

SETI Resources

NASA has recently started a newand very aggressive SETI (search forextraterrestial intelligence) program.In the first few hours of operation,more frequencies have been observedin more ways than have in the entirehistory of all previous ET watching.

One prominent researcher in SETIis Frank Drake. He is famous for the

"Drake Equation" which accuratelypredicts the number of intelligent civ-ilizations and unintelligent senatorsthat are likely to be lurking in theuniverse at any given time. Frank hasrecently authored a new and highlyreadable book titled Is Anybody OutThere? and published by Delacorte.

So, I thought it might be a goodtime to do a resource sidebar on SETI.I’ve included several associations anda listing of the better books.

Besides the three groups Frankmentioned in his book, I’ve added theAmateur Radio Astronomers who alsopublish a Radio Observer newsletter.But note that their main focus is onradio astronomy fundamentals. Andthat they do distance themselves fromET watching and the UFO crowd.

For several reasons, I strongly feelthat the odds for an imminent SETIcontact are quite high. As openers,our signal detection, processing, andcomputing abilities have skyrocketedin the last several years. And should

65.4

Hardware Hacker

SETI RESOURCES

Associations:

Publications:

Amateur Radio Astronomers

Pacific Astronomical Society

Planetary Society

SETI Institute

247 North Linden StreetMassapequa NY 11758(516) 798-8459

390 Ashton AvenueSan Francisco, Califronia 94112(415) 337-1100

65 North Catalina AvenuePasadena California 91106(818) 793-5100

2035 Landings DriveMountain View California 94043(415) 961-6633

Edward Ashpole, , Blandford, 1989.

Issac Asimov, , Doubleday,1972.

John Billingham, , MIT Press 1981.

Howard Blum, , Simon & Schuster 1990.

Ben Bova, , New American Library 1990.

Ronald Bracewell, , Stanford Alumni, 1974.

A.G. Cameron, , W. Benjamin, 1963.

Nathan Cohen, , John Wiley, 1988.

Frank Drake , MacMillian 1962.

Frank Drake, Delacorte Press, 1992.

Robert Forward, , Ballantine 1980.

Donald Goldsmith, , University Science, 1980.

Donald Goldsmith, , Benjamin, 1980.

James Gunn, , New York: Charles Scribners Sons, 1972.

J.S. Hey, , Neal Watson, 1973

John Lilly, , Doubleday 1961.

Thomas McDonough, , John Wiley, 1987.

Greg Mamikunian, , JPL, 1965.

Philip Morrison, , NASA, 1977.

Bernard Oliver, , NASA, 1973.

Dennis Overbye, , Harper-Collins, 1991.

Michael Papagiannis, , Reidel 1980.

Cyril Ponnamperuma, , Houghton Mifflin, 1974.

Robert Rood, , Charles Scribners, 1981.

Carl Sagan, , Simon & Schuster,1985.

Carl Sagan, , MIT Press, 1973

Carl Sagan, , Random House, 1978.

Iosif Shklovsky, , W. Norton 1991

Iosif Shklovsky, , Holden-Day, 1966.

Walter Sullivan, , McGraw-Hill, 1964.

David Swift, , University of Arizona Press, 1990.

Frank White, , Walker, 1990.

Search for Extraterrestrial IntelligenceAsimov’s Biogaphical Encyclopedia

Life in the UniverseOut There

First ContactThe Galactic Club

Interstellar CommunicationsGravity Lens

Intelligent Life in Space

Is Anyone Out There?

Dragon EggQuest for Extraterrestrial LifeSearch for Extraterrestrial Life

The ListenersThe Evolution of Radio AstronomyMan and Dolphin

Search for Extraterrestrial IntelligenceCurrent Aspects of Exobiology

Search for Extraterrestrial IntelligenceProject Cyclops Report CR-114445

Lonely Hearts of the CosmosStrategies for the Search for LifeInterstellar Communications

Are We Alone?ContactCommunications with Extraterrestrial IntelligenceMurmurs of Earth

Five Billion Vodka Bottles to the MoonIntelligent Life in the UniverseSearch for Intelligent Life on Other Worlds

SETI PioneersThe SETI Factor

Fig. 4 – NEW SHARP OPTO CHIPS offer all sorts of new possibilities forwireless communication, safety isolation, and short haul telemetry. The 500kHz pulse modulation ignores ambient light and TV/VCR remotes.

+5v +5v

RY5AT01 RY5AR01

datainput

dataoutput

Recommended range:1 to 36 inches

continue to do so.Shortly after World War II, our sun

suddenly turned into a radio star., , and

became our firstgoodwill ambassadors to outer space.These signals are now light yearsaway from us, and have now sweptout nearly a third of a million

of space.Within this humongous volume are

several hundred "probable" candidatestar systems. Our own signals areeasily detectable at this range withour present state of the electronic art.In another years, morevolume will be swept out with eighttimes more candidate star systemsnow watching .

We are now in transition betweencalling hundreds of candidate starsystems to annoying thousands more.

On the other hand, I personally feelthat looking for obviously modulatednarrow signals in the expected"water hole" frequency band mightnot be the swiftest way to go. If Earthis an even remotely typical example,all the radiated signalsswamp those ones by atleast a zillion to one.

And we have recently discoveredspread spectrum communications. Ifyou really want to punch any signalthrough very high noise over greatdistances, spread spectrum seems avery good way to go. The chances arethat you could step up to multipledimensions of spectrum spreading.

Using, say, frequency, time, andsome sort of a trellis modulation typeof overlay.

Perhaps a "multi-level marketingscheme" in which the unswift couldpick up that something was comingdown, the fairly bright could receiveuseful info, and the superintelligentcould grab the full set of plans. Thissurely would beat sending out primenumbers forever.

The signals may be there but wejust might not be smart enough torecognize them just yet. Perhaps thefundamental question to ask is "Whatspreading and modulation schemewould give us the most bang for thebuck?" And then start looking forsomething similar heading our way.

Let’s have your thoughts on this.

Captain Video Roller DerbyKukla, Fran, & Ollie

cubiclight years

eight times

Your Hit ParadeAt a further signal strength drop of

less than six decibels!

unintentionalintentional

45

45

SETI

65.5

June, 1993

NAMES AND NUMBERS

Cerac Inc

Delacorte Press

GEnie

Gerber Scientific

NASA

NEC

Radio Observer

RF Design

Sharp

Signetics/Philips

Synergetics

Wired

Box 1178Milwaukee, WI 53201(414) 289-9800

666 Fifth AvenueNew York, NY 10103(212) 765-6500


83 Gerber RoadSouth Windsor, CT 06074(203) 644-1551

Langley Research CenterHampton, VA 23665(804) 865-3281


7605 Deland AvenueFt Pierce, FL 34951(407) 464-2118

6300 S Syracuse Way, S650Englewood, CO 80111(303) 220-0600

5700 NW Pacific Rim Blvd.Camas, WA 98607(206) 834-2500

811 E Arques AvenueSunnyvale, CA 94088(800) 227-1817

Box 809Thatcher, AZ 85552(602) 428-4073

544 Second StreetSan Francisco, CA 94107(415) 904-0664

Infrared data communications hasrecently become much simpler thanksto a pair of circuits. Figure oneshows details.

These devices look like a transistorwith a built-in lens. Theirtransmitter outputs a burst of kHzmodulated infrared square waves iffed a logic one. And outputs nothingwith a logic zero. This is a form ofmodulation that’s called

.The receiver accepts an

infrared signal and converts it backinto digital logic levels. An internaldigital filter rejects most interferingsignals or noise.

The modulation scheme largelyignores ambient light. Signals frommost interfering remotesare also strongly rejected. Data ratesup to baud are supported. Thebeamwidth is a somewhat narrow tendegrees, and the recommended rangeis to inches.

Obvious hacker uses include safetyisolation, data comm, handicappedaides, virtual reality, robotics, and forwireless mice.

Because of the narrow beamwidth,the two devices must point ateach other at all times. While there isgood rejection to ambient light andmany random signals, there is noselective coding. Which means thatyou will have to strictly isolate eachoptical linkup from any potentiallyinterfering neighbors. This turns intoan especially sticky problem in fullduplex (two-way) data comm.

Sadly, Sharp’s intro price forthese is in the "What are they on, andwhere can we get some of it?" range.These will be superb products whenthey drop to sixty cents each.

There are all sorts of emerging newuses for shorter range wireless datacommunication. I’d like to apply thegeneric term forany newer method that tries to sendinformation a few inches or a few feetwithout any wires.

We’ve seen one possible need in aprevious column and in my ongoing

reprints.An is a tennis-ball shaped

beastie that you glomp onto an ac

power wire. The isopod automaticallymeasures and transmits the current toa nearby receiver. This can greatlysimplify home energy management.No rewiring, no electricians, and nocode hassles need be involved.

Another new need is for a wirelesspulse rate sensor for use on a bicyclecomputer. And there are thousandsmore. How about an "optical mouse"that senses where you are ? Ornew ways to get data onto or off of arotating shaft or moving vehicle. Orground-loop-free alternatives to datacommunications?

But why don’t you tell me instead?For this month’s contest, eithershow me a use for the andthe , or else dream up abrand new application for short haultelemetry.

There will be dozens of the usual

book prizes awarded, along with anall-expense paid Thatcher,

going to the best of all.Be sure to send your written entries

to me here at and not to editorial.

From , a new and thick chock

full of , and chips. Alsoincluded are their genlocking videoencoders.

From a large packet of datasheets on . Yes,these definitely include the fancy newteachable versions.

is a trade journal whichcovers radio communications in the

and range. Lots of ads forspecialized chips and componentshere. And is a brand new magout of Multimedia Gulch that is quiteinteresting but hard to describe. Thestories so far have included ones oncellular hacking and virtual reality.

Plotter codes appear in the from

. This includes photoplotterand vinyl sign cutter info.

From , a freebie pocket sizeperiodical chart of the elements.

For the fundaments of most digitalintegrated circuits, be sure to checkinto copies of my and

. Both are availableper my nearby ad.

Most of those items I’ve mentioneddo appear in ouror sidebars. Be sureto check here first before calling ourhelpline.


Sharp

AmplitudeShift Keying

directly

short haul telemetry

Hardware HackerIsopod

looking


tinaja quest

Synergetics

SigneticsDesktop Video Data Handbook

NECInfrared Control ICs

RF Design

Wired

PlotData Format Reference BookGerber

Cerac

TTL CookbookCMOS Cookbook

Synergetics

Names & NumbersSETI Resources

RY5AT01500

RY5AR01

TV or VCR

19,200

1 36

IR

$10

BOD

(A)RY5AT01

RY5AR01 (B)

(FOB AZ)

A/D D/A DSP

VHF UHF

Electronics Now

New opto chips

Short haul telemetry

New tech lit

65.6

Hardware Hacker

Don Lancaster’s

July, 1993

Hardware HackerA flying car newsletter

Photopolymer resourcesAmateur television books

Royalty-free real PostScript!BASIC Stamp microcontroller

66.1

Fig. 1 – THE BASIC STAMP is a$39.00 hacker microcontroller usinga Microchip Technology CPU.

PIC16C56

EEPROM

Areminder once again that Ido try to gather most of ourmentioned items into a pairof sidebars. You will usually

find one for all the regular, and a second that targets a

special resource category.We try to triple check all entries.

First by my own research. Second byKathy, our superb proofer and factchecker. And third by editorialspot checks.

To date, I have received over helpline calls asking me for

the sourcefrom two columns back. Well, it wasright where it belonged. Smack dab inthe middle of thatsidebar. Complete with reader servicenumber.

Before calling my no-charge techhelpline, please read the story,double check both sidebars, and havea pencil or pen ready.

As figure one shows us, the from is a brand new hacker computer the size of a

commerative postage stamp. This isbasically a microcontroller,a byte , a resonator anda voltage regulator. Eight linesform your real world interface. Theseare provided for in a breadboard area.

is the supplierof the .

This one is cute as a bug.An approximate schematic appears

in figure two. Burned into the custom is a interpreter. The fully

tokenized instructions are prestoredinto the companion serialand then automatically interpreted oneach power up.

The program and data storagearea is only bytes in theplus an additional internal workingregisters.

No, you can not run multi-tasking on this machine. But since each

tokenized command requiresonly a very few bytes, and since some

fancy macros are available, youcan create surprisingly sophisticated

programs on your own.Program development is normally

done on your host, using the fancyeditor and interpreter provided. Onthe host, you are working directly in

. And have all of your normalresources available. The interpreterthen tokenizes the final program anduploads it to the Stamp via athree-wire cable that connects to yourhost’s parallel port.

Once uploaded, your Stampbecomes a dedicated computer whichcan be used just about anywhere.

Power can come from a clip-onvolt battery. Power consumption is animpressive mils when running and amere microamps when asleep.

Figure three shows the instructionset. Besides all the usual tinycommands, there are some powerfulmacros offered. debouncesinput contacts. With a lot of options.

returns variables to yourhost for debugging and analysis. A

macro offers a direct optionpicking. Just like the commandin fancier languages.

gives you selectable timedelays. is an 8-bit converterthat reads a potentiometer input. Itcan also read a photocell, thermistor,or whatever. can measure theduration of any input pulse with a tenmicrosecond resolution. The similar

command delivers a timedoutput signal.

directly outputs pulse widthmodulation. Adding a resistor and acapacitor can change this to an 8-bitaccurate analog voltage.

Now for the neat stuff. Themacro is a full serial data receiverwith selectable baud rates from to

. This can becomein which you can wait for a specifiedcharacter sequence. directlygenerates serial output data foruse. with an external driver.

A output can producetones and noise effects.

A number generator iseven included. Use this one for whitenoise audio sources or to randomizevideo game effects. Naturally, youcan selectively read, toggle, or writeany individual line. You can alsotemporarily or permanently go intosleep mode. You get out of the sleepmode by cycling your power off andthen back on. Sixteen subroutines areallowed, nested two deep.

The series of microcontrollersuse a non-Von architecture. The

bit instruction words are used inconjunction with bit data words.

The chips by themselves (less anycustom operating system code) can bebought for as little as each.

See the andtheir companion

for additional details.Speeds? The series blows away

pretty near all of their competition inexecution time and code length.

On the other hand, serialaccess for your tokens does slow youdown considerably. But hundreds ofinternal machine language commandsmay get executed at full speed for anyone token fetch. Clock frequencies ashigh as Megahertz can be used. Solong as low power is not critical.

One possible trick: Use theStamp to develop your ap. Then youswitch to plain old machine languagefor full speed and ultra low cost onyour production units.

Much more on the fundamentals ofworking with microcontrollers can be

Names &Numbers

self-qualifying

twohundred

Integrated Circuit Systems

Names & Numbers

entire

BASICStamp Parallax

Microchip Technology

total

very

2

MicroChip Data BookEmbedded Control

Handbook

EN

$39.00

PIC16C56256 EEPROM

I/O

CPU

CPU BASIC

EEPROM

256 EEPROM16

UNIXBASIC

PC

BASIC

BASIC

BASIC

9

20

BASIC

BUTTON

DEBUG

BRANCHCASE

PAUSEPOT A/D

PULSIN

PULSOUT

PWM

SERIN

3001200

SEROUTRS623

RS232SOUND 128

128RANDOM

I/O

PICRISK

12-8-

$2.70

PIC

EEPROM

20

BASIC

A new microcontroller

66.2

Hardware Hacker

Fig. 2 – SCHEMATIC DIAGRAM of the BASIC Stamp.

in gnd

out

1 2 3 4 5 6 7 8 9

18 17 16 15 14 13 12 11 10

RA2 RA3 RTC CLR GND RB0 RB1 RB2 RB3

RA1

RA3 RTC CLR GND RB0 RB1 RB2 RB3

RA1 RA0 OSC CLK +5V RB7 RB6 RB5 RB4

1 2 3 4

8 7 6 5

RA2 RA1 CLK CS

VCC PRE PE GND

PIC16C56

93LC56

I/O

line

#7

I/O

line

#6

I/O

line

#5

I/O

line

#4

I/O

line

#3

I/O

line

#2

I/O

line

#1

I/O

line

#0

4 Mhzpiezo

resonator

breadboarding area

+5v

+5v

+Vin

sipnetwork

+Vin 9-voltbattery

connector

+5 volt source+

programmingconnector

nc

(+)

5 voltreg

.005F

10Fµ µ

found in my older ,volumes I and II.

One potential use for theStamp is shown in figure four. I’vebeen doing a lot of work with thestupendously great PostScript generalpurpose computer language. In fact,this is the language I use forof my electronic design, pc layouts,stock market analysis, schematics,Book-on-demand publishing, and justabout everything else.

All the figures youhave seen here infor years have been done by usingnothing but my word processor andPostScript. Device independently.

The only little problem has beenthat PostScript tends to end up atad on the skimpy side. Usually youonly have three choices: Dirtying upotherwise clean sheets of paper orplastic; writing files to the hard disk;or returning your data back to a hostfor recording or other reuse.

Assume you’ve got a homebrewmachine that has an x-axis and y-axisstepper, an up/down mechanism, anda "both steppers home" sensor. Thiscan be a vinyl signcutter, engraving,or embroidery setup. Or an automatedprinted circuit drill, a wooden sign

router, or a Santa Claus machine.You could use two of your

Stamp lines for serial commwith your PostScript printer. Use twolines for both x-axis stepper phases.And two lines for those y-axis stepperphases. One line for pen or drill orwhatever up/down. And a final linethat zeros only when both steppersare in their home position.

The hidden beauty here is that allof those fancier PostScript fonts andthe level 2 tools immediately becomeavailable for use on your own customhomebrew rig. At unbelievably lowcost. With royalties!

Do let me know if you want moredetails. Meanwhile, I’ve posted lotsmore on PostScript to .

In particular, be sure to check out for an intro PostScript

tutorial, and for lots ofdetails on vector output. I’ve also gota free PostScript secrets brochure toget you started.

Ferinstance, say you lash up yourown vinyl sign cutter. You use yourPostScript printer to create, debug,and proof all the artwork. Then youcan capture the graphic paths byusing PostScript’s rather powerful

and operators.Next, you use -like codeto vectorize the captured paths.

Finally, a series of commandssends your cutting sequences out theserial port where the Stampcan act on them. Should any longersequences be needed, serial feedbackcan be used with a sequenceto wait for task completion.

The really big hacker breakthroughthat everyone is waiting for is aautomated printed circuit drill. Thenew Stamp used along with aPostScript printer seems to give us abrand new handle on this project.

I recently noticed that dentist’s airturbines cost only . Junkers mightend up free from a reasonably curiousdentist. The handle on most drills isusually empty. These turbines can becut down to the size and roughly themass of a plotter pen. It sure wouldbe interesting to see if they provideenough power for board drilling.

Let’s restrict our goals initially to a board. An system might

introduce all sorts of bad mechanical

Micro Cookbooks

only all

camera readyHardware Hacker

The Stamp can instantly letyou extend the genuine Adobe LevelII PostScript to any personal projector machine of your choosing!

zero

GEnie

flattenpath pathforall

print

readchar

BASIC

I/O

BASICRS423

PSRT

STARTUP.PSPOSTVECT.PS

POSTVECT

BASIC

$199

BASIC

$30

4" x 6" X-Y

BASIC

Homebrew PostScript hacking

Thoughts on a PC drill

66.3

July, 1993

Fig. 3 – INSTRUCTION SET FOR THE BASIC STAMP. The macros marked(*) above make the stamp surprisingly powerful.

BRANCHBUTTONDEBUGEEPROMEND

FOR…NEXTGOSUBGOTOHIGHIF…THEN

INPUTLET

LOOKDOWN

LOOKUPLOWNAPOUTPUTPAUSE

POTPULSINPULSOUTPWMRANDOM

READRETURNREVERSESERINSEROUT

SLEEPSOUNDTOGGLEWRITE

Option picker similar to a CASE command.*Read and debounce mechanical input.*Send register contents to host.*Store data in memory.Go into sleep mode until power cycles.

A looping construct.Execute subroutine. Jump to another location in program.Make the chosen I/O pin high. Conditionally execute instructions

Make selected pin an input. Optional definition. Includes add, subtract, multiply hi/lo, idivide, modulo, min, max,AND, NAND, OR, NOR, XOR, and NXOR.*Search table for match.*

Read values from table.*Make the chosen I/O pin low.Enter sleep mode for a selected time.*Make the chosen I/O pin an output.Short selected time delay.

Read a potentiometer (8-bit A/D convert).*Measure input pulse width.*Output pulse of selected width.*Output pulse width modulation (D/A convert).*Generate pseudorandom number.*

Read variable from memory.Return from subroutine.Change direction of selected I/O pin.Read serial input and interpret format.*Format and output serial data.*

Long selected time delay.Output musical notes or white noises.*Change state of selected I/O pin.Store data to memory.

problems. Instead, the board could bemoved along a single axis. The drillcould be moved along a second axis.And it might be simplest to yourboard, rather than drop the drill. Ormaybe use a raising cam and gravityfeed on the turbine.

My current thinking for a stepperwould be the linear . Whilekinda pricey, this does offer twentypounds of force in two mil steps. And

offers some dandynew peripheral driver chips.

Let me hear your thoughts on thisgreat new project.

I have long been fascinated by the. These are just plastic

compounds of one breed or anotherwhich are only partially cross-linkedduring manufacture. A later exposureto light and a development processwill selectively harden portions of thematerial. Which can result in a statechange from liquid to solid or a shiftin dissolvability.

The results could be used for etchresists, a 3-D model, a Braille sign, arubber stamp, a printing plate, anintegrated circuit mask, a silk screenmaster, or a vinyl stick-on letter. Orfor zillions of new aps.

Because of fundamental chemistry,most photopolymers demand strongultraviolet light for exposure. Threeminutes using a contact printer out indirect sunlight often will work well.Photopolymers are typically

, hardening in the presence oflight.

This month, I thought our resourcesidebar might give you a rundown ofthe more hackable photopolymers.

The classic one you might be mostfamiliar with is spray-on etch resist,often in the form of by

. And stocked by .More modern substitutes are the

such as those nowoffered by . These are bothuniform and pinhole free. They alsodevelop with sodium triphosphate, alow cost garage floor cleaner.

is a fine stocking supplier ofprinted circuit supplies. A good tradejournal here is .

Photopolymer solder mask resistsare also readily available.

Photopolymers offer lots of optionsfor silk screen printing. The leading

film supplier is , while, , and

offer smaller quantities., the folks, have a

number of interesting photopolymerproducts. One is known as .Actually, this is more a diazo-likeprocess, but it uses the same drill ofcontact print exposing and wiping onglop to alter selected areas. What youend up with is a clear polyester sheetthat has translucent or opaque colorareas selectively applied to it. Dozensof color options. Lots of graphic artsuses here.

Their imaging productsseem great for labels and prototypedialplates. Typically, you will have awhite self-stick vinyl having a coloroverlay. You then selectively removethe color by exposing. Then you use awiper pad to develop. Any "reverse"effects get done by using positive art.

Aluminum backed versions are alsooffered. Price is in the per squarefoot range.

The photopolymers have long beenessential for printing asused on cardboard containers. Oneleading supplier for the materials inlarger quantities is , while

is a wholesale source inmore modest amounts.

The same material can make great"rubber" stamps. Any "real" rubberstamp will be pink or black, while aphotopolymer stamp will be clear totranslucent. The photopolymer onesoften last longer and provide sharperimages. Of the many rubber stampphotopolymer suppliers,

and the are my favorites.

We’ve seen in previous issues howSanta Claus machines are starting torevolutionize prototyping. A leading

lift

Hurst

Texas Instruments

photopolymers

negativeacting

EastmanKodak Radio Shack

dryfilm photoresists

Dynachem

Kepro

Circuits Assembly

Ulano AdvanceProcess Supply Southern SignDick Blick

3-M Scotch Tape

Color Key

Dynamark

flexographic

MerigraphR. A. Stewart

GranthamPolly-Stamp M&R MarkingSystems

SLS

KPR

$8

Fun with photopolymers

66.4

Hardware Hacker

PHOTOPOLYMER RESOURCES

Advance Process Supply

Dick Blick

Cooley Sign Systems

Dynachem/Thiokol

Dynamark

Eastman Kodak

Grantham Polly-Stamp

IMEC

Jet USA

Kepro Circuit Systems

Kimoto

M&R Marking Systems

Merigraph

Southern Sign Supply

RA Stewart

3-D Systems

3M/Color Key

Ulano

400 N Noble StreetChicago, IL 60622(312) 829-1400

Box 1267Galesburg, IL 61401(800) 447-8192

50 Esten AvenuePawtucket, RI 02860(800) 992-0072

2631 Michelle DriveTustin, CA 92680(714) 730-4200

3M Center Bldg 220-7W-03Saint Paul, MN 55144(800) 241-4819

343 StateRochester, NY 14650(716) 724-4000

418 Central Avenue NEEast Grand Forks, MI 56721(218) 773-0331

Rt 4, Box 79Monell, MO 65708(417) 235-3053

1116 MacDate BoulevardCollingdale, PA 19023(800) 528-1153

630 Axminister DrFenton, MO 63026(800) 325-3878

2915 182nd StreetRedondo Beach, CA 90278(213) 370-7411

100 Springfield AvenuePiscataway, NJ 08855(908) 562-9500

Box 3064Naperville, IL 60566(800) 323-1832

127 Roesler RoadGlen Burnie, MD 21060(410) 768-8600

641 S Palm, Unit HLa Habra, CA 90631(310) 690-4445

26081 Avenue HallValencia, CA 91355(805) 295-5600

3M Center Bldg 223-2N-01Saint Paul, MN 55144(800) 328-1303

255 Butler StreetBrooklyn, NY 11217(718) 622-5200

Fig. 4 – THE BASIC STAMP can be used as a royalty-free interface to let youapply real Adobe PostScript level 2 to any old homebrew project!

BASICStamp

task feedback

task commands

x-axisstepper

y-axisstepper

penup/down

homesensor

PostScript laser printer

vinyl cutter,wood routing,

milling machine,animation stand,awards engraver,

embroidery lashup,circuit board drilling,Santa Claus machine,

etc. etc. etc…

firm here that uses ultraviolet curingphotopolymers is . Moreon Santa Claus stuff in future issuesand the reprints.

The photopolymer that I am reallywaiting for is a vinyl one which hasonly been partially cross linked. Youdo your PostScript artwork master onyour laser printer and then you’llcontact print. Expose and then wipeon some glop. A repositionable andpre-weeded cut vinyl letter or a logoresults. Without needing a costly signcutter. I do keep hearing persistentrumors of these. But no results.

Meanwhile, there are now two newproducts that come close.

One of these is thatsystem by . This is basically aself-stripping "rubylith". While greatfor its intended graphics art strippingpurposes, you are stuck with red, andthe results are not repositionable.

The other one is known as. This

is an opaque white and fully outdoorrated reinforced vinyl. Color glop hasbeen preapplied to its surface. In yourchoice of seventeen flavors.

A magic developer will dissolve. To do this, put a vinyl

cover (or any suitable mask) onto thematerial. Then simply scrub the coloraway in selected locations.

In the daylight, you have a colorover white. At night and backlit youget white light or translucent colorsper your selection. Neat stuff. Sanelypriced. And eminently hackable.

Finally, there is an interesting newvariation on photopolymer printingplates that should open up all sorts ofnew hacker ideas. The folksare using photopolymers for Brailleand other low cost raised lettersignage. What you really have here isa metal plate with some raised plasticselectively applied exactly where youwant. Unique business cards are onepossibility.

There is a slight chamfer to theirresin, improving the appearance. Costis in the twenty cents per square inchrange. Jet’s processing equipment isridiculously expensive, but it shouldbe easy enough to fake.

Their photopolymer offers a veryhigh durometer. Free samples.

Needless to say, hacker workinvolving photopolymers can be verymuch improved by using PostScript.

3-D Systems

Hardware Hacker

Etch-n-PeelKimoto

CooleyBrite Eradicable Sign Material

only the color

Jet USA

any

ADA

66.5

July, 1993

NAMES AND NUMBERS

1545 Lee StreetDes Plaines, IL 60018(708) 298-2269

SPACEGolden, CO 80401(303) 273-3321

3000 Poberezny DriveOshkosh, WI 54903(414) 426-4800


Box 326Princeton, IN 47670(812) 385-2564

PO Box 968Valley Forge, PA 19482(215) 666-1900

PO Box 1125Tellevast, FL 34270(813) 356-2788

Box 54960Los Angeles, CA 90054(310) 692-5911

2355 W Chandler BlvdChandler, AZ 85224(602) 963-7373

6700 Discovery BlvdMableton, GA 30059(800) 645-7270

6359 Auburn Blvd Ste CCitrus Heights, CA 95621(916) 721-8217

E11870 Shadylane RoadBaraboo, WI 53913(608) 356-3647

338 8th Avenue SouthEdmonds, WA 98020(206) 778-0423

5555 Zuni SE #281Albuquerque, NM 87108(505) 298-9362

13980 NW 58th CourtMiami Lakes, FL 33014(305) 557-8222

Box 809Thatcher, AZ 85552(602) 428-4073

PO Box 809066Dallas, TX 75380(800) 336-5236

23072 Lake Center Dr #100El Toro, CA 92630(714) 855-3838

Amateur Television Quarterly

Colorado School of Mines

EAA Aviation Center

GEnie

Hurst Manufacturing

Integrated Circuits Systems

Dan Levels

McMaster-Carr

Microchip Technology

MSC

Parallax

Resonance Research

Roadable Aircraft

Rotary Flight International

Small Parts

Synergetics

Texas Instruments

Don Thompson

Full details on . One littleknown capability of PostScript is its

ability. This lets you getthe final size of your printed circuitlayout exactly right, even on a printerwith sloppy tolerances and paper thatswells or shrinks.

In flexographic printing and otherplaces where images stretch as theyare bent around a drum, anamorphicscaling using PostScript gives you afast, simple, and accuracte fix.

Let’s have two contests this month.Either dream up a new ap for the

Stamp, or else see if youcan come up with some non-obvioushacker use for photopolymers.

As usual, there will be a dozen orso of my recently updated

book prizes,along with an all-expense-paid

AZ) for twogoing to the very best of all.

Be sure to send your entriesdirectly to me here at my ,and not to editorial.


We have a super selection of newgoodies this month. For great booksand mags on , try out the

folks.Gyro Gearloose is alive and well!

is a unique labor oflove Ron Borovec newsletter for allof you flying car enthusiasts. Similarpubs includefrom the and the

from

All the fundamentals of telephoneoperation are well covered in a newself-published

by Dan Levels. is a new book

by Michael Fumento. It explores thenature of evidence and statistics in ascientific controversy, and does covereverything from the Alar worries to

radiation. In a typical chapter,strong evidence is given that alcoholis one outright scam rather than anyuseful motor fuel. Grain alcohol usesmuch more energy than it deliversand increases air pollution. This oneis a must read.

The justcompleted their fourth

symposium.Mostly on underground radar used formining, caving, and archaeologicaluses. Proceedings are available.

A video on is now

available from .New videos, parts kits, and training

seminars on laser printer repairs areavailable through .

now ships a new andfree . These folks run thegreatest robotic resource in the world.They have everything your hardwarestore never heard of. And then some.

is a alternatethat carries extensive local stocks ofmachine shop supplies and hardware.They are also a no-hassle source ofthe wires and dielectric oils. A

page catalog is offered.Turning to my own products, my

newcontains lots of self-publishing info;and my new gives youinsider access to scads of my secretsupply sources. Or if you really wantto get into PostScript is a big way, trymy package. See mynearby ad for more info.

Over on , I have justadded , a review of hamradio magazines. Or ,nonlinear graphics tutorial (use whenmapping stuff onto oddball surfaces).Also a reminder that I have arrangedfor a newer and faster signup.Have your modem dialThen type to set your baud rate.When promped, enter your temporaryaccess code of .

A reminder here that most of thesources mentioned also appear in the

appendix.Names & Numbers

Designing and BuildingHigh Performance Tesla Coils

Resonance Research

Don ThompsonSmall Parts

Catalog #14

MSC McMaster-Carr

Book-on-demand Resource Kit

Resource Bin I

Whole WorksSynergetics

GEnie

GEnie

GEnie

microsizing


Thatcher, tinaja quest

writtenSynergetics

Amateur Television Quarterly

Roadable Aircraft

Experimental AircraftEAA Aviation Center

Experimental Rotorcraft RotaryFlight International

Tech Notes from aTelephone Engineer

Science Under Siege

Colorado School of MinesSubsurface

Exploration Technology

BASIC

PSRT

(B)(A)

(FOB

ATV

ELF

EDM2000

PSRTNUTS17.PS

NONLINGR.PS

(800) 638-8369HHH

XTX99005,SCRIPT

Electronics Now

Two contests

New tech lit

66.6

Hardware Hacker

Don Lancaster’s

Hardware HackerAugust, 1993

Single station FM trapsFM DX reception updateFree GPS receiver boardsResources for "free energy"Nonlinear graphic secrets

67.1

Fig. 1 – TYPICAL FANCY GRAPHIC MAPPINGS. Only the "isometric" figureat the lower right can be done with a stock linear graphics transform. Theothers require use of nonlinear transform techniques.

ISOMETRICISOMETRIC

ISOMETRIC

The logjam seems to befinally breaking up. We havealready seen where

offers a GlobalPositioning Satellite receiver forin single quantities.

Better yet, has dumped their Backpacker’s receiver to

the yuppy surplus resellers.stocks these at . But our helplinelore says they are grossly overpriced,even at one-third the original list.

Best of all, has announceda receiver front end at .Along with their companionsix-channel correlator. Plessey offerspretested receiver boards. Freeyou can show them any credible planfor engineering a product.

We’ve seen in previous issues how is a great trade journal for

keeping up on the latest and the bestdevelopments in personal nav.

We have a mixed bag of goodiesfor this month…

I have long been fascinated by themapping of images onto distortedsurfaces. For "star wars" lettering ordrawing on a sphere. Or perspectivestorefronts. Or words on a blowingflag. Or logos on a rootbeer cup.

I’ve found PostScript to be idealfor this sort of thing. Let’s do a quicksummary and then find out where togo for the full set of plans.

There are two key tools needed forfancier graphic mappings. These arethe and theexotic .Several examples of what you can dowith these appear in figure one.

We have already found out abouttransforms in previous columns andin those reprints. Atransform is just a way of taking onegroup of numbers and playing trickswith them to create a new group ofnumbers. The new group will end upsomehow "better." Or more what youhave in mind.

In the case of a two-dimensionaltransform, all you do is take a pair of and values and change them into a

new pair of and values that are"elsewhere." The relationship of the"elsewheres" determines the mappingyou end up with.

Fancy matrix math techniques areusually used for graphics transforms.Plain old ninth grade algebra can getused just as well. The linear graphicstransform is simply…

x' = x + y + y' = x + y +

You could view as the. is the amount of . is

the . is the amountof . is the . andis the .

To move a figure around on yourpage, you change and . This iscalled . To make a figurelarger or smaller, you change the sizeof and . This is known as .Usually, you’ll scale and by the

same amount. Otherwise you’ll get an scaling that gives you a

compression or an extension.Make negative, and you’ll get a

special case of scaling that prints orimages . Make negativeand you go . Or do bothfor, of all things, .

Rotating a figure gets tricky. Youuse some trig sines and cosines on ,

, , and . You might use fanciercombinations to do fancier mappings.For instance, that mappingshown in figure one can be done witha linear transformation.

The of the transforms iscritical. Scaling and then translatingis vastly different than translating andthen scaling. Sure, if you do knowexactly what you are doing, you canuse one single transform to translate,rotate, and scale all at once.

You can do a surprising amount of

GPS

$390

GPS

$599

GP1010 IC $21GP1020

GPS

GPS

A B CD E F

AB C

DE F

C F

A EA E

A

E

AB D E

TrimbleNavigation

SonyPYXIS

x' y'

Damark

Plessey

if

GPS World

linear graphics transformnonlinear graphics transform

Hardware Hacker

x y

horizontalscale lean

horizontal offsetclimb vertical scale

vertical offset

translation

scaling

anamorphic

isometric

sequence

backwards

both

upside down

Nonlinear Graphics

67.2

Hardware Hacker

Fig. 2 – THE NONLINEAR "scribble"transform can make computer artless exact and precise.

Fig. 3 – FM DX SETUP gives a 145 mile range with a 24 foot antenna height.

two-setsplitter

+10 dbamplifier

To receiver #1

To receiver #2

Radio Shack 15-1117

Radio Shack 15-1141

Winegard CA-6065

stuff with a plain old linear mapping.A square could get changed into anyother square of any chosen size andorientation and position. Or into anyrectangle, line, or point. You can alsomap into a parallelogram. Or copyany number of times.

But note you can use a lineartransform to convert your square intothe needed for perspectivelettering. Or to draw on a sphere. Orto scribble. Nonlinear techniques arerequired for any of these tricks. Sincethat linear transform is well known

and fast to implement, you usually doa nonlinear transform by alinear one.

In a linear transform, the valuesthrough are that stay the

over the entire mapping. To doa nonlinear transform, you can define

through as which mayneed recalculated for each and everypoint of the mapping.

Recalculating and retransformingevery point can take a very long time.You may have to do this if you arerectifying an aerial photograph.

Instead, you normally want to tryand use some whichmakes use of graphic . Thislets you nonlinearly transform

of a line segment. Or onlythe control points of a curve. A lineartransform is then used for everythingbetween. Which ends up ridiculouslyfaster and more compact.

Four examples of these graphicalprimitives are custom , ,

, and procs. Usedrespectively for positioning, straightlines, curved line segments, and pathcompletion operators.

Nonlinear mapping with primitivesshould appear "perfect" so long aseach straight line ends up as a straightline on the final image. But if you tryto map onto a sphere or do anythingelse where any straight lines become

curves, you’ll get into severe problems. Ferinstance, you

might end up running yoursphere instead of along its surface.

The workaround here is to changeany longer straight lines into shortersegments of "unbent" curves. Thiscan give you reasonable results whilestill letting you use sparse data.

Each nonlinear transform will endup different, depending on whateverfinal effect you are after. In general,what you do is intercept your anddata values used for positioning andstraight lines, or your eight

for any curves. Then for thatparticular and value, you will thenrecalculate any of the "constants"through which might be sensitive toyour current position. Finally, you dothe usual linear data transform.

The isometric figure can be doneusing an ordinary linear transform,since squares are being mapped intoparallelograms. Rather surprisingly,the perspective mapping canbe done with a linear transform. Onlya single calculation of ( - y/y ) needbe done nonlinearly ahead of time.

This is for an architect’sperspective. In which all the verticallines remain that way, regardless oforientation.

The spherical transform is based onlongitude and latitude. Some simplemultiplication by sines and cosinesdo the transformation for you.

The glyphpath transform is verysubtle and stunningly powerful. It letsyou automatically squash and stretchindividual elements as they go alongthe curve.

You first start with an underlyingpath that should get broken up into asequential group of straight line andsimple curved path elements. Thenew transform then places yourvariable your path and yourvariable to your instantaneouspath position. Thus always goes toyour immediate right or left as youwalk along the curve.

The glyphpath transform is bestused on "fairly narrow" glyphs. If youget too far from a path which is tootightly turning, you can "inside out"the glyph. With horrible results.

Take apart your next soda cup andlook at the lettering. Note how the art

AF

A F

AF

1not

trapezoid

modifying

constantssame

variables

sparse data setprimitives

onlythe ends

moveto linetocurveto closepath

cornercutting

through

x y

controlpoints

x y

almost

2-point

xalong ynormal

y

0

Doing the Transforms

67.3

August, 1993

Fig. 4 – SINGLE STATION FM TRAPS are hard to design because of theextreme Q values needed. Here are three creative alternatives.

Unwanted station sitsin a deep null and isvery weakly received.

Wanted station receivedat best possible strengthconsistent with good null.

(A) Use of antenna pattern to "throw a null" at the interference. Thewanted station is purposely misaligned from optimum.

Antenna#1

Antenna#2

Two-setcombiner Receiver

points toUNWANTED

station

points toWANTED

station

AttenuatorPhaseShifter

(B) Phase cancellation uses two antennas and adjusts the amplitudeand the phase of the interfering signal to cancel itself out.

TeeAntenna Receiver

Around 214 feet of high quality coaxshould end up 117 quarter wavelengths(and a high impedance) at 93.3 Mhz;and 118 quarter wavelengths (and alow impedance) at 94.1 Mhz.

Short end of stub.

(C) Coax "long line" trap provides a high impedance at the wantedfrequency and a low one at the unwanted frequency.

has to get fatter as you move to thetop of the cup.

The "rootbeer" transform is reallydrawing onto a truncated portion of acone. values go radially, whilevalues go tangentially.

Similar techniques can be used for"star wars" lettering, for twisted filmeffects, stretched banners, or art on awaving flag. Flag waving could bebased upon a mapping between twoBezier cubic splines.

Another nonlinear mapping trick isshown you in figure two. Very often,computer art ends up looking like itwas done on a computer. Too exactand precise. Nonlinear techniques canget used to let you scribble. Makingthe results as ratty as you want. Heresome random numbers are introducedinto the nonlinear mapping.

I’ve posted a complete tutorial andlots of plans for nonlinear transformsup to my as my file

. Rumor has it this onemight also show up in the December

issue of . Or, I’llbe happy to throw in a free copy withany order.

There’s also another dozen files upon that give you specifichands-on details on specific nonlineartransforms. Included are starwars,perspective, sphere, rootbeer, banner,tuna can, glyphpath, flag, twistedfilm, and several others.

We did look into the reception ofdistant stations a number of timesin the past. I thought I’d give you arundown of just what I’m now using,along with several newer schemes forfurther improvement.

Figure three shows you my presentsetup. I’ve now got this humongous

antenna up onthe roof. I used a fixed two-mastmount pointing due west. While thisslightly cuts the Phoenix responseand badly hurts Tucson, it is cheapand rugged. And we do get some highwinds here. The antenna height isaround feet above ground.

The antenna signal goes to a coax inline amplifier.

This can make the antenna load moreuniform and gives you decibels ofgain to comp for the line losses and

signal distribution. On the other hand,the amp probably adds cross-mod anddistortion. Results probably wouldend up about the same without it.

The amplified signal is then routed

to a coax two-set splitter. One outputdrives a high quality receiver in theliving room. The other runs throughwhat used to be the cable system tosource an el-cheapo receiver in

PSRT #719NONLINGR.PS

1993

PSRT

FM

#CA-6065

24

#15-1117

10

FMy s

GEnie

PC Techniques

Synergetics

Winegard

RadioShack

For More Info

FM DX Update

67.4

Hardware Hacker

"FREE ENERGY" RESOURCES

PO Box 1472Huntsville, AL 35807

Rexarch, Box 19250Jean, NV 89019


2011 Crescent DriveAlamogordo, NM 88310(505) 434-0234

Rt 2, Box 35EBowling Green, MO 63334


PO Box 716Amherst, NH 03031(603) 673-4730

3410 Frankfort CtOxnard, CA 93033

1304 S College AvenueFort Collins, CO 80524(303) 482-3731

PO Box 538Bradley, IL 60915(815) 935-5353

191 Promenade du portageHull PQ CANADA J8X 2K6(819) 777-9696

E11870 Shadylane RoadBaraboo, WI 53913(608) 356-3647

PO Box 703Buffalo, NY 14226(716) 636-1425

PO Box 392Dayton, OH 45409(513) 298-7116

Box 121873Chula Vista, CA 91912(800) 398-2056

3 Amy LaneQueensbury, NY 12804(518) 792-1003



A.D.A.S.

Amazing Archives

Borderland Research

Consumertronics

H&A Industries

High Energy Enterprises

Information Unlimited

Innovative Electronics

Int’l As for New Science


Planetary As Clean Energy

Resonance Research

Skeptical Enquirer

Super Science

Tesla Book Company

Tesla Coil Builders Association

Tesla Society

Whole Earth Review

my computer room.The key test here is good old

in Mesa, miles away. Thiscomes banging into the good receiverwith full stereo and total quieting. Onthe cheap receiver, it is very hard totune, slightly noisy, and mono only.The problem is a watt randomnoise source at that is only a mileand a half away.

The shielding on a cheap receiveris purposely left off so they get localstations without an antenna.

, that Phoenix stationdoes come banging in at on bothsets so strong that you can arc weldwith it. At miles range.

How can you improve on a scenewhere a strong local station overloadsa weak and desired one?

First and foremost, the quality ofbetter grade receiver front endshas improved greatly. Key advances

are transistors having low crossmod and excellent overload specs.And four-quadrant linear multipliersare replacing those flakey old mixers.Getting a newer receiver might help alot. A mid- to high-end car radio canbe a good choice here, because of itsbetter shielding.

Naturally, real coax should alwaysbe used instead of twin lead.

But there are some things you cantry that may help. Some of these areshown you in figure four.

I was very surprised that you can’tcheaply pick up a simple one station

trap. These aren’t even availablein or other cable-tv suppliers.After making several calculations and

talking to some crystal filter folks, Ifound out exactly why.

The problem is that exotic highcomponents are needed that also haveextreme temperature stability. As ageneral rule, bandstop filters get uglybelow percent bandwidth and justabout impossible at the percent orbetter often needed for this ap.

The ordinary caps and coils simplywon’t hack it. Instead, you have to goto exotic crystals, helical resonators,or transmission line components. Onpassive filters, you have insertion andmismatch losses that could kill anydesired but weaker signal. Add gain,and you may pick up cross mod andoverload problems that get you rightback to square one.

One obvious solution is to perform filtering, instead of

filtering. Any fancy antenna will haveone or more deep which, whenpointed directly at any station, couldattenuate it by decibels or more.

Instead of pointing your antennadirectly at your desired station, you’llcarefully it to

. For instance, yourdesired station might now come in atad weaker. But the unwanted one canbecome strongly attenuated.

A second scheme sometimes getsused in radar systems. This one getscalled . What youdo is point your main antenna at thedesired station. A smaller antenna ispointed . You thencombine your two signalsthrough a two set coupler. After verycarefully adjusting the amplitude andthe phase of the second input signalto give you equal amplitude anddegree phase.

Phase is adjusted by changing thelengths of the cables involved."trombone" lines should be findableas surplus. Amplitude changes can bedone using variable resistors or otherattenuators.

The theory is to get your residualinterfering signal small enough that itdoesn’t cause cross mod when it hitsthe receiver.

A is a possiblethird interference reduction hack. Ashorted transmission line looks likean open at quarter wavelengths.And appears as a short at quarterwavelengths. In theory, the shorts andopens repeat for longer cable lengths.

93.3KDKB 145

50,00094.1

KJZZ NPR91.5

158

FM

FET

FM

Q

30.5

30

180

VHF

Note that any old random hackerjunk inserted between your correctlymatched antenna and any properlydesigned receiver is much more likelyto hurt you than help.

Anixter

spatial frequency

nulls

misalign throw a nullat the interference

phase cancellation

at the interferencebackwards

long line canceller

oddeven

67.5

August, 1993

NAMES AND NUMBERS

PO Box 2133Bremerton, WA 98310(800) ALPHA11

8101 E Prentice #210Englewood, CO 80111(303) 740-8949

PO Box 9045Waltham, MA 02254(800) 877-8775

Box 29900Minneapolis, MN 55429(800) 729-9000

1262 E Katella AvenueAnaheim, CA 92805(714) 385-1707


5500 Highlands Pkwy, Ste 450Smyrna, GA 30082(800) YEL-4HAL

1245 Home AvenueAkron, OH 44310(216) 633-8460

5724 W 36th StreetMinneapolis, MN 55416(612) 920-7393


340 E First StreetDayton, OH 45402(800) 338-0531

7721 E Gray Road #204Scottsdale, AZ 85260(602) 483-0192

1500 Green Hills RoadScotts Valley, CA 95067(408) 438-2900

PO Box 28Whitewater, WI 53190(800) 558-9572

1818 South Hwy 441Apopka, FL 32703(407) 886-8860


9 West 57th Street, 43rd FlNew York, NY 10019(212) 371-5800

PO Box 809066Dallas, TX 75380(800) 336-5236

585 N Mary AvenueSunnyvale, CA 94086(800) TRI-MBLE

3000 Kirkwood StreetBurlington, IA 52601(319) 754-0600

Alpha Supply

Anixter

Biltrite

Damark

Eletech

GEnie

Home Automation Laboratories

Hygenic Manufacturing

Industiral Arts Supply

Linear Technology

Parts Express

PC Techniques

Plessey

Premium Parts+

Sawtek

Siemens

Sony

Texas Instruments

Trimble Navigation

Winegard

Let be any old number. Now,has to be some number. Everytime. And has to be annumber. By definition.

Let’s do a quick calculation to findthe length of cable neededto get an odd number (and an open) at

and an even number (and a short)at Mhz…

n n

Which solves as n .Your wavelength at 94.1 is

meters. A quarter wavelength will be meters. And of these will be

velocityfactor, and this equals roughlyfeet of coax.

So, take feet of coax, and thensolidly short the end and wrap it upinside a well shielded and groundedpaint can. Add a connector to yourmain antenna line. After carefullyadjusting for an exact length, whattheoretically should happen is a deadshort at and an open at . Forreception at other frequencies, youdisconnect the coax. Or change itslength suitably.

If the wanted station is thanthe unwanted one, you should use nand n instead.

Sadly, the length of the cable willseverely attenuate the depth of thoseshorts and opens. And you probablywon’t get nearly the you need, evenwhen using premium coax.

It might be worth trying, though.Or perhaps something similiar donewith stripline on a PC board could getdecent with acceptable size.

In general, these transmission linecomponents can be cheap and usefulsubstitutes for high parts. But themath gets tricky and special test gearmay be needed.

Smith Chart techniques can behandy here. Again, check

for do-it-yourself Smith Charts.Tellyawhat. Let’s work up a new

group hacker project and a contestout of this. For the usual

book prizesplus a possible all-expense paid Thatcher, for two,either send me the measuredband reactance plot of a long piece ofshorted premium coax, or elseshow me a single station FM trap thatworks. Cheap and hacker-friendly, ofcourse. And easily retuned.

As usual, be sure to send all yourentries directly to , ratherthan on to editorial.


I got a surprisingly high number of"free energy" enthasiasts calling andwriting over our recent coverage ofthe heat engine basics. I was bemusedby those of you using biblical quotesto disprove the thermodynamic laws.

There was one minor error in thecolumn. Rankine’s name was spelledwrong. Sorry about that.

To me, looking for any free energysounds really dumb. Firstoff, because

the odds of finding any are pitifullylow. Second, because others will seeyou as being a few chips shy of a fullboard. Lastly, unlimited free energyis in the least desirable in anyway, shape, or form. Free energywould hasten the isoentropic heatdeath of the planet.

Which would be the most heinouscrime against humanity imaginable.

Nearly all free energy experimentsinvolve bad or missing labwork. Ortheories that are not even wrong. Orblatant misinterpretation of the data.Or ignored hidden factors that maskwhat is really coming down.

Or plain old outright cons.

93.394.1

93.3 (2 + 1) = 94.1 (2 )

2 = 1183.19

0.80 11894 meters total. Assume a 0.7

214

214

T

94.1 93.3

22 -1

Q

Q

Q

PSRT

(FOBAZ)

(A) FM

(B)

n 2neven

2n + 1 odd

minimum

higher

GEnie


tinaja quest

Synergetics

not

Electronics Now

"Free Energy" Resources

67.6

Hardware Hacker

Quoting Carl Sagan, "Extraordin-ary claims all require extraordinaryevidence." It is not enough to claimsomething is happening. Instead, youmust have absolute proof which isincontrovertable and overwhelming.

Proof far above experimental noiselevels. And well within the statisticalbounds. And free of hidden factors.And easily and openly duplicated byanyone, anywhere, anytime.

That’s what the scientific method calls for.

Now, I am very much in favor ofencouraging individuals to check outoddball, unpopular, or controversialtechnical areas on their own. That’swhat hardware hacking is all about.But your odds of any success shouldend up far higher if you stay withinthe guidelines dictated by the laws ofphysics and electronics.

It turns out there is a rather lively"free energy" industry. These includespecialty booksellers, associations,conferences, and individual authorswho publish books, papers, projects,and kits. Just for kicks, I thought wewould gather all of these together asthis month’s resource sidebar.

Why? Well, first because they arethere. Second, because even the freecatalogs can be wondrously bizarrereading. And, finally, because manyof these publications are textbookperfect examples of how to doresearch, how to do tech writing,and how to desktop publish.

Let’s do a quick rundown of someof the major players: Start with

, who offer a wideselection of topics ranging from freeenergy to perpetual motion to Teslato intergalactic happy faces on Mars.These folks also run conferences. Arecent spinoff here is the

, who dooffer similar services and publish the

.A Canadian group is the

.Two unique outfits are

who focus on paranormaland free energy theories. They alsopublish their

. Is this ever. Boy, a wholeflock of ‘em flew over that time. And

is now heavy into the alternatemedical electronic therapies.

Or, for the "more miles per gallon"miracle carburetors, you can try

. Competing offers appearin all those fine print classifieds in

, ,and their many clones.

Checking the classifieds in reveals

heavy intoand . And

on antigravity and on "300suppressed technologies".

Nikola Tesla seems to be the centerof much "free energy" research. Thekey problem is that Tesla was both abrilliant inventor a superb conartist. Four additional resources thatfocus on Tesla are the(who publish ),the , the

, and. The latter custom builds

museum-quality exhibits.An outfit known as stocks

papers including by T. Bearden. The key

circuit Beardon describes as neededfor extracting the "zero-point scalarenergy from the fabric of space" haslong been available as theby .

I find it somewhat strange that theLinear Technology engineers haven’tnoticed their oscilloscopes melting orall their test benches vaporizing whentesting these chips.

There are several outfits offeringtechnical kits and plans based on the"Don Britton" model of one personoffering a bunch of self-designed lowbudget projects. The engineering onthese designs ranges from impeccableon down to missing completely. Twofirms here includeand .

Of course, isa unique source for any obscure techbooks. They stock several fascinatingperpetual motion titles.

I would very much like to get acomplete list for all the free energyresources. So, as a third contest forthis month, just tell me about any Imay have missed. If possible, sendme a catalog or else get me on theirmailing list.

Finally, the old .Written mostly by high profile and"name brand" scientists who attemptto debunk pseudo-tech, junk science,and claims of the paranormal. Sadly,a lot of their debunkings are handledwith such manic religious fervor that

they become what they are attacking.But these are still great reads.

Through , acombined catalog on industrial artsand tech education products. Includedare injection molding machines, heatformers, and casting products. Thisone is a "must have".

The is a new and freenewsletter on surface wave acoutsicaldevices from .

From , a fat catalog oftools and findings for jewelers androckhounds. Plenty of obscure toolshere with great hacker possibilities.

Those hard-to-find pin SuperNinny game cartridge connectors areoffered by . Anotheruseful source of and camcorderstuff is .

From , some freesamples of their newlow cost, high power drivers. Theirtriple looks quite handy forconverting any car alternator into apower stepper motor.

A new incandescent lamp ordimmer that makes use of pulse widthmodulation is available as the

from . Cavers are sure toscoop this up for helmet lights.

A reminder that is asuperb labor-of-love newsletter fortechnical items of interest to cavers.And lots more details on all sorts ofvery unusual or oddball publicationsappears in the reprints.And, of course, in bunches of filesnow up on .

One source of lower cost digitalvoice technology is . Remotecontrols, security devices, and relatedhi-tech goodies are offered by

. A pair ofreasonably priced sources for sheetrubber products include and

.For the fundamentals of starting up

your own technical or craft business,you might check into my

, availableper my ad.

A reminder that I have arranged fora new and faster signup for my

RoundTable. Refer to the box for details. Genie has just

sharply reduced their rates and now isa really great buy.

See you there.

always

notnot

not

HighEnergy Enterprises

NationalAssociation for New Science

New Science NewsPlanetary

Association for Clean EnergyBorderland

Research

Journal of BorderlandResearch

Lor’d

H&A

Industries

Popular Science Popular Mechanics

WholeEarth Review Super Science

Orgone Energy BlanketsRife Resonators Amazing

Archives

and

Tesla SocietyExtraordinary Science

Tesla Bookstore Tesla CoilBuilder’s Association ResonanceResearch

The Final Secret ofFree Energy

Linear Technology

ConsumertronicsInformation Unlimited


Skeptical Enquirer

Industrial Arts Supply

SAW Scene

SawtekAlpha Supply

Parts Express

Premium Parts+Texas Instruments

Power+Arrays

Siemens

Speleonics

Resource Bin

GEnie

Eltech

HomeAutomation Laboratories

BiltriteHygenic Manufacturing


Synergetics

GEnieNeed

Help?

LTC1073

A.D.A.S.

72

VCR

TIPC2301

LED

BTS629

PSRT

PSRT

New Tech Lit

Don Lancaster’s

Hardware HackerSeptember, 1993

Pulse monitor resourcesNew wireless comm magAn update on free energyAerobic exercise softwareThermoelectric guidelines

68.1

Fig. 1 – HEAT PUMPING CURVE for a larger thermoelectric module. Notethat the efficiency goes down as the temperature differential increases.

0 25 50

Temperature differential in degrees C

0

10

20

Heatpumpedin watts

20 watts of heatacross 0 degrees.Efficiency is .



LOW

VERY LOW

ZERO

An update to last month’s freeenergy resource sidebar: The

newly releasedtheir page proceedings from theirlatest

. AtMost of the major players show up

here, along with bunches of historicalreferences. All of the usual topics arecovered – antigravity, Reed motors,pulsed magnetics, zero point scalarenergy, homopolar generators, Teslaearth resonance, perpetual motion,element transmutation, cancer cures,alternate fusion, the whole bit.

My own personal view is that thisis one fascinating and wonderouslybizarre work of fiction. I do feel thatmany of the papers presented exude adistinct aura of outright hogwash.

On the other hand, step numberone in researching any controversialtopic is to find out who is doing whatto whom. Even a totally absurd and"not even wrong" notion can lead togenuinely useful and innovative newconcepts. Forums should exist for allcontroversial thought. Which makesthis one definitely worth a look.

Judging by the helpline calls lately,there seems to be a lot of interest inthe solid state thermoelectric coolersnow cropping up surplus. Sadly, mosthackers don’t pick up on the fact thatthere are several rude surprisesawaiting when they try to use these inthe real world.

So, one more time: These thermomodules are inefficient andneed good heatsinks. Theyare strictly limited to very low poweruses. They also simple andobvious heat flux calculations whichlots of hackers positively refuse tomake. For most hacker uses most ofthe time, the

.Let’s see why this is so.Solid state thermoelectric modules

using the cooling effect weredeveloped over three decades ago andhave not changed or improved one

whit since. The players change everyfew years in an industry that’s beenchronically unprofitable. One currentsupplier is . They do offer datasheets and design notes.

Figure one shows a typical heatpumping curve for the larger twentywatt module. Applying a dc currentacross the device causes heat to bemoved from one surface to another.This module might need fifteen voltsat three amps for operation.

Note that the heat pumped dependsinversely on your temperature dropacross the device. Yes, you can pumptwenty watts of heat through atemperature difference. Or you canpump zero watts of heat across adegree temperature difference. With,of course, efficiency.

More typically, you’ll want to bothpump heat and have a high delta-T. Anormal operating point might be adegree drop when pumping watts.

The module data sheets carefullybury their efficiency figures for mostnormal operating points. Often,watts of energy are required to moveone. This is an

of a laughable . Comparethis against a air conditioner with

an of . Or a Japenese one witha superb of .

The low efficiency would not be allthat bad if all of the excess heat wasnot generated in the wrong place atthe wrong time. But what you havedone when you use a module is

heat precisely where you aretrying to eliminate it.

Let’s use an aquarium cooler as anexample. Now, there is another namefor any large aquarium. It is called a

. So, let’s takeour super efficient heatsink and thenremove some heat from it. Because ofthe module inefficiency, we mayhave to add three new watts of heatfor every one removed and put it intoa new heatsink.

Naturally, we would not want thenew heatsink to rise up as far aboveambient as the aquarium goes below,or we will simply be heating up theambient air. So, we’ll shoot for anoutput temp rise of only a quarter thecooling drop.

International Association forNew Science

International Symposium onNew Energy

very

extremelyextremely

demand

thermoelectric coolingmodules simply do not work

Peltier

Melcor

zero

zero

three

Energy EfficiencyRating

add

It is trivially easy to pick up moredelta-T rise between your module hotside and ambient than the delta-Tcooling the module is providing!

super efficient heatsink

Your final heatsink will have to be

540

$49.50.

50

2510

EER0.33

US

EER 12EER 17

TE

TE

Thermoelectric review

68.2

Hardware Hacker

Fig. 2 – USE THESE GUIDELINES for all of your thermoelectric moduledesigns. Otherwise, you are likely to end up heating instead of cooling!

1. The area to be cooled be superinsulated. All avoidable sourcesof heat gain be carefully excluded.

2. Realistic heat flux calculations and heatsink thermal impedancecalculations be carefully made ahead of time.

3. Current thermoelectric modules are an inappropriate solution if morethan twelve watts of actual cooling are called for.

4. The rise of the module hot side temperature above ambient bekept as low as possible. This rise must exceed a small fractionof the total temperature drop desired.

5. Very large and extremely high quality heatsinking is a must. Useforced air cooling at the very least. Pumped water cooling may berequired to achieve an acceptable efficiency.

6. Power sources have very low ripple and hum, since the ripplepeaks heat much worse than the troughs cool.

7. Surfaces contacting the module be ultra-flat. 100% contact isessential. Thermal grease always be used.

mustmust

must

mustnever

must

mustmust

Fig. 3 – THE MYSTERY WAVEFORMS inside a typical "chest type" pulsemonitor revealed. The transmitted signal approximates a 36 cycle burst of 5kilohertz sinewaves. One burst per pulse event. What you really have here isplain old inductive coupling using an air core transformer.

Conductivepickuppads

Bandpassdifferentialamplifier

Automaticgain

control

Leveldetector

Impulsegenerator

Ferriteloop

antenna

(C) To produce this transmitted waveform…

(B) Generates this burst of six micropower impulses…

(A) This approximate block diagram…

16A handy way to do this is to simplyuse a second aquarium which istimes larger.

Just how much heat are we talkingabout here? That’s what doing heatflux calculations is all about. Let’sreview the basics.

The two key numbers you have tolook for are your

and your. Going on back to square

one, a , oris the amount of energy needed toraise or lower the temperature of onepound of water by one degree F.

There are around eight pounds ofwater per gallon, so eight ’s areneeded to shift the temperature of agallon of water by one degree F. Atemperature change of one perminute will occur when watts ofpower are input.

Heat flux ends up proportional totemperature difference. For a givenheatsink, you’ll get twice the delta-Tfor twice the watts passed through.Math similar to plain old Ohm’s lawdefines the .

A typical ordinary heatsink mighthave a thermal impedance of betweentwo and ten degrees C per watt. If thethermal impedance is five degrees perwatt and if you are transferring eightwatts, the thermal rise will be a totalof forty degrees.

To get below one degree per watt,you usually have to go to forced aircooling. To get under half a degreeper watt, a pumped water cooling isoften the best choice.

The key problem with solid statethermoelectric coolers is that

Ferinstance, you might have yourmodule doing a degree cooling,but your heatsink hot side might havea degree rise above ambient. Thenet result is ten degrees of .The exact opposite of what you aretrying to do.

Not to mention moving to a muchless efficient point on the moduleresponse curve.

In the case of the aquarium, youcan easily measure your heat flux.The results will depend on the surfacearea of the aquarium, the ambient airflow, the temperature drop required,and the amount of water present.

Temporarily remove the fish andfill the aquarium with ice water. Butotherwise leave it run with the usuallights and pumps and whatever. Next,carefully measure your temperature

time as the ice melts and slowlyreaches room temperature. The

times better than your aquarium!

watts of coolingrequired heatsink thermalimpedance

BTU British Thermal Unit

thermal impedance

the heatrise of your hot side of the moduleabove ambient can easily exceed thenet cooling of the module itself!

heating

vsRadio

TE

16

BTU

BTU17.58

30

40

TE

68.3

September, 1993

Fig. 4 – AEROBIC EXERCISE RECORD written in PostScript. Fully editible source code appears on GEnie PSRT.

0 10 20 30 40 50

EXCERCISE TIME IN MINUTES

50

75

100

125

150

175

0

5

10

15

PULSE

RATE

BICYCLE

SPEED

targetzone

speed

pulse

Marvin GriblinskiTuesday, June 22, 1993

Route: Whitlock loopDistance: 7.4 miles.Maximum speed: 14.5 mph.Average speed: 11.0 mph.Miles to date: 1145 Comments: Good day. Mild winds. Loose gravel improving.

Previous resting pulse: 74Previous standing pulse: 86

Recovery pulse at 0 seconds: 110Recovery pulse at 20 seconds: 107Recovery pulse at 40 seconds: 104Recovery pulse at 100 seconds: 97

digital thermometeris ideal for this.

Then plot your temperature riseversus time on a graph. Next, find the

of the warming curve, in degrees per

minute. To hold the target temp, thedegrees per minute cooling neededwill equal the degrees per minutewarming taking place.

Multiply the pounds of water timesthe degrees per minute of coolingneeded to get the ’s per minuterequired. Multiply this by to getyour cooling watts needed. Finally,multiply by some fudge factor like

for a safety margin.The chances are the final cooling

power required will be oftimes higher than what can be doneusing modules.

I haven’t actually run this warmingtest, but I’d guess that watts ofcooling would not be an unreasonablevalue for a larger aquarium to be keptfairly cool.

And if you do burn up three wattsof inefficiency for every single watt

pumped, something like watts ofheat will have to go out through yourheatsink. With a one watt per degree

rise heatsink, the module hotside temperature will try to go todegrees.

Otherwise known as a fish fry. of the twenty watt modules

would be needed!Do those new thermoelectric

coolers work? I’d be willing to betthat if you removed the cooler andcoupled the heatsink directly to the

chip itself, the results would endup as good or better. Simply becauseyou are not adding extra heat at apremium where you don’t want it.

A related story: Years ago therewas this total federal solar fiascoinvolving a school in the rural south.This was to be a pilot demonstrationproject of a solar adsorption cyclecooler. The results weren’t quite asgood as expected, so they added anew five ton evaporative cooler to theoutput to improve the heatsinking toambient air. Sure enough, the coolingthen met spec.

Then someone asked this ratherembarassing question: How muchevaporative cooling would have beenneeded if the solar adsorbtion coolingwas never in use at all? The answer?

Using modules for many hackerapplications can end up the same asbuilding a bonfire inside an icebox.

Are there any places at all where modules can be used? Certainly.

you have carefully made your heatflux measurements. And you areonly moving tiny amounts of heat outof a superinsulated region. And youare dumping into a big heatsink withan unusually low delta-T.

You also have to use super smoothsurfaces, proper thermal grease, andavoid ripple in your power supply.The tiniest amount of ripple will foulthings up because the ripple troughsheat six times better than the peakswill cool.

Naturally, trying to freeze ice isbeyond the pale.

Figure two shows some guidelinesfor proper use of modules.

Shack

slope at yourtarget temperature

hundreds

Thirty

Three tons!

If

if

if

all

#277-0123

BTU17.58

1.5

TE

300

1200

C TE1200

CPU

CPU

3:1

TE

TE

TE

68.4

Hardware Hacker

PULSE MONITOR RESOURCES

Box 5490Evanston, IL 60204(708) 491-9628

33 East Minor StreetEmmaus, PA 18098(215) 967-5171

5148 Saddle Ridge RoadPlymouth, MI 48170(800) 742-4478


2994 W Liberty AvenuePittsburgh, PA 15216(412) 343-9666

29100 Aurora Road #200Solon, OH 44139(216) 248-1125

99 Seaview BlvdPort Washington, NY 11050(516) 484-2400

15 Corporate DriveOrangeburg, NY 10969(914) 365-3500

PO Box 4099Farmingdale, NY 11735(516) 293-3751

3016 NE Blakeley StreetSeattle, WA 98105(800) 522-3610

1700 45th Street EastSumner, WA 98352(800) 426-4840

Box 35311Canton, OH 44735(216) 455-1162

801 W Madison StreetWaterloo, WI 53594(800) 879-8735

14553 Delano St, Ste 210Van Nuys, CA 91411(818) 780-8808

ACT USA

Bicycling Magazine

Creative Health Products

Dialog

Medical Electronic Products

Medical Equipment Designer

Polar

Precise International

Pulse Stick II/Claggk Inc

RacerMate, Inc

REI

Synapse Enterprises

Trek

Vetta/Orleander USA

These modules can be a sure firewinner for most science fairs, whereyou can easily feel all the heat goingfrom your thumb to your finger. Evenwith a single alkaline or lithiumcell. They are also quite useful forchilled mirror dewpoint instruments.And handy in high vacuum aps wheremoving parts are a no-no.

modules are great for coolingmicroscope stages, special astronomyinstruments, and infrared detectors.But the modules don’t seem usable insatellite dishes because the gain dropsfaster than noise figure improves.

What are the practical alternates to modules? Small compressors are

not that big a deal. Obvious sourcesare drinking fountains, refrigerators,icemakers, and reworked auto airconditioners. One source of info onthese is . A drinkingfountain compressor will only need

watts of new energy to pump .But the neatest substitutes for

modules are called .This second cousin to a perpetual

motion machine seems to blatantlyviolate thermodynamic laws. They donot, of course.

A vortex cooler is simply a magicTee-shaped pipe. No moving parts atall. You blow ordinary air into themiddle, and hot air comes out one endand cold air out the other. Down to

Farenheit temperatures and tonsof cooling.

Leading suppliers includeand . Some important uses arefor electronic cooling and stoppingneedle breakage on industrial sewingmachines.

I would guess that a vortexcooler could be done very simply andeasily. And would work ridiculouslybetter than a module. As far as Iknow, nobody has even tried.

Do not ever attempt tobuild up your own units of this type!What follows is not in any manner tobe construed as medical advice.

I’ve been developing some aerobicexercise software for a client. UsingPostScript, of course. Which I havefound to be the greatest universalhacker’s language anywhere ever. I

have also been looking closely at thepulse monitors and have found somefascinating new electronic conceptsthat you might wish to expand uponone way or another. These conceptsshould apply beautifully to short haultelemetry apps.

But be careful to heed allthe above warnings.

One way to deal with exercise, ofcourse, is to get yourself a cornedbeef and pork fat sandwich, add ahelping of Eggs Benedict, and chowdown until the urge goes away. Thereare others who do feel that sustainedexercise programs provide positivebenefits towards longevity, physicalconditioning, well being, and for useas medical therapy.

The harder you exercise, the higheryour heart rate. An (or "withoxygen") exercise attempts to set up a

elevated pulse rate over afairly long time period. Say half anhour to an hour for cycling, groupaerobics, swimming, jogging, or fastwalking.

A conditioning target zone mightbe to percent of the maximumheart rate. This max rate in turn candepend upon sex, age, and upon theadvice of your physician or aerobicsinstructor. Ferinstance a year oldmale might have a target zone ofto beats per minute.

The old "thumb and stopwatch"method of measuring pulse rate hassome obvious problems. Not the leastof which is that it woefully disruptsthe program in progress. There areinstead two popular new methods tomeasure pulse, the ,and the .

The plethsymograph is based onfinger or toe capillaries expandingand contracting with each pulse beat.Shine infrared light on through yourfinger, and its transmission will varywith your pulse. Opacity depends onhow much blood is present. You canthen amplify, condition, and digitallyaverage these variations to extract thecurrent pulse rate. Cheaply, simply,and noninvasively.

Infrared plethsymographs are easyto find, even as the specials atK-mart. Unfortunately, many of thesesimply do not operate properly inaerobic exercise situations. The mainproblem involves .Any relative motion between sensor

Contractor

vortex coolers

VortecExair

Warnings: Do not ever modify antype pulse monitor any way for

any reason!

please

aerobic

target zone

plethsymographEKG sensor

motion artifacts

"D"

TE

TE

60 300TE

-40

CPU

TE

60 75

30114

142

$19.95

EKG-HVAC

Some pulse monitor discoveries

68.5

September, 1993

NAMES AND NUMBERS

Rt 1, Box 41Cutler, IN 46920(317) 268-2214

1250 Century Circle NorthCincinnati, OH 45246(513) 671-3322


4320 196th SW, Ste B-111Lynnwood, WA 98036

1350 East Touhy AvenueDes Plaines, IL 60018(708) 635-8800

1304 S College AvenueFort Collins, CO 80524(303) 482-3731


120 San Gabriel DriveSunnyvale, CA 94086(408) 737-7600

1040 Spruce StreetTrenton, NJ 08648(609) 393-4178

524 San Anselmo Avenue #107San Anselmo, CA 94960(415) 455-9330

8338 Colombard CourtSan Jose, CA 95135(408) 238-8082

8030 South Willow StreetManchester, NH 03103(603) 668-2499

PO Box 809Thatcher, AZ 85552(602) 428-4073

3625A SW Murray BlvdBeaverton, OR 97005(503) 644-3535

10125 Carver RoadCincinnati, OH 45242(800) 441-7475

Box 650Morris Plains, NJ 07950(201) 292-5100

Antique Radio Laboratories

Exair

GEnie

Heath Nostalgia

HVAC Prod News/Contractor

Intl Assn for New Science

Linear Technology

Maxim

Melcor

Mondo-tronics

Oughtred Society

Resources UN-LTD

Synergetics

TriQuint Semiconductor

Vortec

Wireless Design & Development

and finger will give a false output andhighly erratic results. Infuriatinglyso. To the point of being useless.

Better yet, there are or"chest type" monitors that directlymeasure the electrical activity of theheart. These usually are offered intwo pieces, a small chest strap, and astopwatch-type display that is eitherworn on your wrist or mounted on thebicycle or other exercise gear.

The cost of these systems is oftenin the to range. But they aretotally free of motion artifacts. Andyou can check your pulse atany time during the activity. Simplyglance at the display. These also offersettable alarms that trip if you wanderoutside your target zone. Clock andstopwatch functions are included.

One typical unit is the distributed by

and stocked by such yuppy outdoorstores as . I did try this one incombination with a bicyclingcomputer. A second brand is .You could also get a combo monitorand bike computer in one unit, suchas the also offered by

. At list.

The chest unit is totally sealed andhas an internal battery. In normal use,it gets replaced every year or two.The internal battery is purposelyreplaceable to guarantee that the unitremains unmodifiable. There are verystringent regulations over anythingelectronic which directly attaches toyour chest.

Obviously, the chest unit acts as atransmitter and the wrist unit servesas a receiver. The effective range istypically four feet or so.

But what gets transmitted how?The answer to this one is yet anotherstunningly beautiful example of ourongoing quest for elegant simplicity.

What we really have here is moreshort haul telemetry. But one that hasto remain totally sealed, be compactand lightweight, reliably run foreverunder micropower, and literally be athrowaway item. At five bucks maxmanufacturing cost.

The secret is a plain old inductivecoupling. Figure three shows thesecret waveforms involved. What youreally have here is a kilohertz aircore transformer, with the primary in

the chest unit and the secondary inthe wrist or handlebar receiver. Eachpulse gets converted into a cycleburst of kilohertz sinewaves.

You can very easily monitor thesewaveforms. Just take any old coil,such as the fifty foot roll of

hookup wire. Add an iron core,such as a handy pair or pliers. Centerthe coil near the chest unit. And thenwatch the results on your scope.

A pair of conductive pads pick upthe signals on either side. Thesemicrovolt-sized signals are stronglyamplified in a bandpass amplifier.There is probably some type ofautomatic gain loop to standardizethe output levels. Then, a comparatorof some sort derives a digital outputfor each pulse event.

Each pulse event then generates aseries of six digital impulses. Eachimpulse is around microsecondswide and has an interpulse spacing ofone millisecond. For a one kilohertzrepetition rate.

If very low power is your goal, youcannot use any kind of linear amp foryour transmitter. Instead, the antennais simply a kilohertz resonant coil.The plots found in my

tell us the of this coil isaround or so.

To transmit a signal, the resonantantenna coil gets whapped

. The high of the coilfills in during the intermediate cycles.If you do look at your scope displayvery carefully, you will observe themodest exponential decay of all theintermediate cycles between impulsewhappings. The long rundown timeafter the last whapping is also quiteobvious.

The spacing of the impulses can betightly controlled. Which elegantlyminimizes any need for super preciseor ultra stable antenna tuning.

Only the bandpass amplifier drawscontinuous current. Both and

do make suitableamps that consume only microamps.

EKG-style

instantly

Edge HeartRate Monitor Polar

REITrek

Favor

VettaREI

not

RadioShack

Active FilterCookbook

once everyfive cycles

MaximLinear Technology

$70 $200

HR-1000$95

5

365

EKG

AGC

80

5

Q20

Q

How do they work?

68.6

Hardware Hacker

NEW FROM

Box 809-REThatcher, AZ 85552

(602) 428-4073

DON LANCASTER

SYNERGETICSVISA/MCFREE VOICE HELPLINE

HARDWARE HACKINGIncredible Secret Money Machine II 18.50Hardware Hacker Reprints II or III 24.50Blatant Opportunist Reprints 24.50Resource Bin Reprints 24.50The Case Against Patents 24.50Ask The Guru Reprints I, II or III 24.50CMOS Cookbook 24.50TTL Cookbook 24.50Active Filter Cookbook 24.50Micro Cookbooks I or II 19.50Lancaster Classics Library 119.50

POSTSCRIPT STUFFPostScript Secrets (IIe/Mac/PC) 39.50Book-on-demand resource kit 39.50Intro to PostScript VHS Video 39.50PostScript Beginner Stuff 39.50PostScript Show & Tell 39.50PostScript Cookbook (Adobe) 18.50PostScript Ref. Manual II (Adobe) 29.50PostScript Program Design (Adobe) 24.50Type I Font Format (Adobe) 15.50Acrobat Reference (Adobe) 24.50LaserWriter Reference (Apple) 19.50PostScript by Example (McGilton) 29.50Real World Postscript (Roth) 22.50PostScript Visual Approach (Smith) 22.50Thinking in PostScript (Reid) 22.50Undst PS Pgrmmg (Holtzgang) 29.50The Whole Works (all PostScript) 349.50

In absence of any pulse input, there isno output and no transmitted signalsent. Even when a burst gets sent, theduty cycle to generate the burst is

and the duty cycle of the burstitself is typically or so.

The average current ends up quitelow. Very elegant.

X-raying the unit revealed a fewsurprises. A large lithium coin cell isused. The antenna is a ferrite rod,long axis horizontal that is apparentlytuned by unwrapping a few turns. Itgets resonated by a polystyrene cap.A pin integrated circuit drives theantenna. This is probably a plain oldgrunt quad gate.

The majority of the input circuitryis discrete and consists of ninetransistors and assorted resistorsand caps. Several special techniquesare required for proper noise rejectionand ultra low power operation.

The receiver is just a resonant coiland a bandpass amplifier that inputs

into typical micro current stopwatchcircuitry. This amplifier apparentlyshuts itself down in the absence ofany transmitted signals. The receiverbattery can get replaced and lasts ayear or more. An averaging algorithmis used to smooth out the results for astable display.

A sample printout for a routineexercise session is shown in figurefour. The complete PostScript code tocustom run these on your favoriteword processor appears on

as .You could build up an automatic

data acquisition system to automatethe whole process. But it is simplerand cheaper just to use a one-handcassette recorder every five minutesand talk the speed and pulse rate to it.With practice, it takes less than twominutes to transfer the data.

I’ve gathered several places to gofor more info on pulse monitors intoour resource sidebar for this month.

offer a freecomparison guide for many of themore popular monitors.

Let us have a bunch of differentcontests this month. Show me someother uses for inductive coupling inshort haul telemetry. Or find me theactual schematic of some typepulse monitor. Or find a hackablesource of pulse monitor chips.

Which should be ideal for one ofmy power line monitors.

Or run the aquarium ice warmingtest. Or show me a genuinely usefulhacker ap for modules that worksin the real world. Or show me someother off-the-wall uses of PostScriptfor new data-to-plot applications.

There’ll be all the usual book prizes

along with an all-expense paidThatcher, for twogoing to the best of all.

As usual, be sure to send all yourentries directly to , ratherthan on to editorial.


is a newbook on the history of engineering at

by Fred Hapgood. A really goodread. But by far the best part is Fred’srevival of a very ancient seven-word

def of what engineering is all about:.

That says it all.Lots of night vision electronics and

surplus infrared viewers are availablefrom . They havea free brochure waiting for you.

A new book on the history of from .

has afree catalog on all their products forradio restoration buffs. Included arecustom pins, adaptors, bases, and coilforms. They also stock manuals forolder test equipment.

The exists for thecollectors of traditional slide rulesand related calculating instruments.Named for the seventeenth centuryslide rule inventor. for meetingsand classified ads.

is a project bookfrom on working withthe shape memory "muscle wires" forrobotics and similar uses. Includedare fifteen easy-to-build projects andlayout templates. for the book;

for book and wires.From , a

newdata book. Mostly on new microwaveintegrated circuits such as low noiseamplifiers, mixers, downconverters,and stages.

isa new trade journal on new productsfor the emerging personal microwavecommunication services. Free subsare offered to industry insiders.

As we’ve seen a number of timesin past columns, any hardware hackerinvolvement with the patent system isvirtually certain to end up a net lossof time, energy, money, and sanity.Mostly because of all the outrageouspopular mythology which surroundspatents and patenting. A mythologythat is almost always dead wrong.

I have put together my new reprint package that

includes several hundred pages ofproven alternates to patenting. A bigdirectory of hundreds of the inventororganizations is included. Check mynearby ad for more info.

A reminder that I have arranged fora new and faster signup for my

RoundTable. Refer to the box for full details. Genie has

recently sharply reduced their ratesand now is a really great buy.

GEnie

Creative Health Products

isopod


tinaja quest

Synergetics

Up the Infinite Corridor

MIT

A sense for the fitness of things

Resources Unlimited

Heathkit Heath NostalgiaAntique Radio Laboratories

Oughtred Society

Motorless MotionMondo-tronics

TriQuint SemiconductorData Communication Products

Wireless Design & Development

CaseAgainst Patents

Synergetics

GEnieNeed

Help?

10:180:1

14

CMOS

SOT24

PSRT #751 EXERCISE.GPS

EKG-

TE

(FOBAZ)

$9.95

$20

$18$29

AGC

PSRT

Electronics Now

New tech lit

This month’s contests

Don Lancaster’s

October, 1993

Hardware HackerMagic resources listing

Dialog and Usenet accessData compression secrets

Alternator to stepper videoGaining comm transparency

69.1

Fig. 1 – THE DIALOG INFORMATION SERVICE is newly available on a lowcost cash-and-carry basis. Of their 400+ data bases, I use these the most.

Book Review Index –

Books in Print–

CA Search –

Career Placement –

Compendex –

Computer Database–

Conference Papers –

Current Contents –

Derwent World Patents –

Dialog Quotes –

Dissertation Abstracts–

Electric Power Database –

Encyclopedia of Associations –

Energy Technology –

Federal Register –

Foundation Directory –

Geobase –

INSPEC–

Magazine Index –

Mathsci–

Microcomputer Index –

NTIS –

Peterson’s College Database –

Publisher’s and Distributers –

Scisearch –

Thomas Register–

Ulricht’s Periodicals–

U.S. Patent Abstracts–

Two million reviews of books and periodicals.

Everything published by author, subject, title.

Ten million entry chemisty data base.

Professional employment resumes.

4500 engineering and technology journals.

Full text of most computer magazines.

Offers 100,000 scientific and technical papers.

Contents of leading scientific and tech jounals.

Has six million worldwide patents.

Stock and option prices, delayed 20 minutes.

All advanced degree dissertations since 1861.

Commercial power R & D projects.

Lists 81,000 organizations worldwide.

Database for the US Department of energy.

Everything by the government printing office.

Lists 32,500 organizations that give money away.

Geography, geology, and ecology data base.

Physics, electronics, and computing data base.

Covers 500 popular magzazines.

Abstracts for math, computers, and statistics.

Articles from 50 microcomputer journals.

National technical information service database.

Complete guide to US colleges.

Who publishes what, when, and where.

Multidisciplinary index to science and technology.

Directory of all manufacturers of everything.

Lists 100,000 publications in all fields.

A complete patent repository.

Ccontacting and intelligentlycommunicating with thosein the know can often end upa serious hardware hacking

problem. So can finding out who haswritten what, when, and where.

But this month, there’s been a pairof really big happenings that maketwo crucial hacker resources cheaperand far easier to use…

The is often called. This is a giant national computer

network which connects virtuallyschools and universities, all researchoutfits, most high tech firms, and thelarger government agencies. Unliketypical systems, there’s no sysopas such. Nor any central repository.

For instance, mere afterthat Fermat’s last theorem had beensolved, the proof was spreading likewildfire on Usenet. I’ve uploaded acondensed proof outline to my

as . We alsogo out of our way to abstract most ofUsenet’s PostScript traffic.

Nearly all insiders in any technicalfield have Usenet addresses. But thetrouble has been that Usenet accesshad to be done through a sponsoringorganization. And becoming a Usenetsponsor involves big bucks. So accessby individuals was by invitation only.

has recently opened a newUsenet email gateway. There is nosurcharge for this access; its just partof GEnie’s low hourly rate.

Let’s say someone has a Usenetaddress of…

To email them from GEnie…

That trailer does the linkup for you. Similarly, say you want toreach me through myGEnie email address. Use a…

…as a Usenet address. For anyoneelse, just add the…

trailer to the email address.Because my works on shared

information, answers for a technicalemail question get directly posted tothe RoundTable. A two hourresponse time is typical.

Oh, yeah. There’s a convention inany Usenet message. One thatbe strictly and rigorously obeyed atall times. A simple "yes"or "no" answer will do. Theseare mostly academic folks youare dealing with here.

Instead, you’ll first describe everywire that your message travels over.Then you give your entire genealogyon back to your great grandmother’scousin twice removed.

Then you quote verbatim anything

and everything anyone else has eversaid on the subject, back to day one.

Then you say your "yes" or "no" inas oblique a manner as possible. Thensay something that is supposed to befunny. Then quote something longand somewhat literate that Chekhovwould find totally obtuse.

Finally, issue a disclaimer that agaggle of Byzantine lawyers wouldfind bulletproof. Then say goodbye.

Aim for a bare minimum of half amegabyte per yes-no email messageresponse. Otherwise "they" will spotyou as a rank outsider.

I’ve long recommended the. For Dialog can

give you instant answers to techquestion in field of study. From

Usenet Anarchy101

all

minutes

GEnie

GEnie

SYNERGETICS

GEnie

must

Be verbose!never

DialogInformation Service

anyany

BBS

PSRT #753 FERMAT.TXT

PSRT

PSRT

UNIX

[email protected]

[email protected]@INET#

@INET#

[email protected]

[email protected]

Usenet

Dialog

69.2

Hardware Hacker

Fig. 2 – THE ASCII CHARACTER CODE. Since ASCII is really a seven bitcode, it repeats twice in 8-bit space. The "high ASCII" area can alternately beunused, a different character set, graphic plotting commands, internalmachine flags, or other symbols. Hex, decimal and octal values are shown.

\040

32

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! " # $ % & ’ ( ) * + , - . /

0 1 2 3 4 5 6 7 8 9 : ; < = > ?

@ A B C D E F G H I J K L M N O

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L M N O

P Q R S T U V W X Y Z [ ] ^ _

‘ a b c d e f g h i j k l m n o

p q r s t u v w x y z ~

NUL SOH STX ETX EOT ENQ ACK BEL BS HT LF VT FF CR SO SI

DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US

NUL ETXSOH STX EOT ENQ ACK BEL BS HT LF VT FF CR SO SI

DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US

SP

SP

DEL

DEL

\

\

|

|

–0 –1 –2 –3 –4 –5 –6 –7 –8 –9 –A –B –C –D –E –FLOWER HEX VALUE

0–

1–

2–

3–

4–

5–

6–

7–

8–

9–

A–

B–

C–

D–

E–

F–

UP

PE

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X

VA

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E

anywhere. At any time. Last count,they had some citationsin stock. All as abstracts and many infull text. In major data bases.

Even paying their traditional perminute rate, I felt Dialog had been by far the fastest, cheapest, and the mostreliable way I have ever found to doresearch.

Dialog also offered a quarter pricelate evening service. But you had tosubscribe to this on your own. Andprecious minutes could easily gobbleup if you were not extremely carefulwith your keystrokes. And if thingshung up, so did your bill.

Dialog has now turned their entireafterhours marketing to .Who in turn has made it available to

. Type DIALOG for access.The really big breakthrough here is

that there are no more by-the-minuteDialog charges. Instead, the setup is

strictly cash and carry. A la carte.And with sharply reduced prices.

A search will typically cost you if you find something and

if you don’t. The abstracts, in lots often, can cost you a total of . That’s

per citation or abstract!Some fancier searches cost more.

There’s also a featurewhere a few data bases can be lookedinto at once. Plus hard copies. Plus

access. And more.I’ve tried to list a few of the more

hacker useful Dialog data bases infigure one. I guess I tend to use their

data base from the alot. This one is strong in electronics,computers, and physics. Two similarbases are and .

But do not forget all the every daystuff. Like ,

, the, and the .

I’ve recently found some new waysto do data compression. Fast, simple,and cheap. So, I thought we might goover the fundamentals here…

Your unit of data measure is theeight bit . As many bytes as areneeded get combined to create a totalmessage, image, program, page,song, video field, or whatever.

A byte may be sent all bits at oncein form. Out a parallel portor through a interface. Or a bytemay be sent in form, one bit ata time. Typically over any serial port,

, , or .hardware or software convertsfrom parallel to serial and back.

Any 8-bit byte has got possiblestates. If all of these states are neededfor the data itself, you are said to bein a format. If, instead, you aremostly interested in sending out textinfo as letters and numbers, you arein an format.

The code appears in figuretwo. code was originally only

bits long and corresponded to possible states. of these were

reserved mostly for your upper casealphabet. Another for your lowercase alphabet. Yet another got setaside for numbers and punctuation.And a final for "invisible"

such as linefeeds, carriagereturns, bells, the end-of-file markers,tabs, or backspaces.

To make into an 8-bit code,it is simply repeated twice. Once withthe most significant bit clearedto zero and called . Andonce with the set to a one andcalled . Sometimes onlylow actually gets used. Othertimes, the high area might bereserved for an

, for , or for for oddball characters.

There is a thorny problem in using comm for data transmission.

The channel is oftenin which certain characters (such ascarriage returns) are used for systempurposes. Nearly all standard serialcomm is non-transparent.

Should a random byte in an imagehave the same code as an end-of-file

CompuServe

GEnie

thirty cents

supersearch

MathSci Compendex

Books in Print Ulricht’sPeriodicals Encyclopedia of As-sociations Thomas Registry

byte

parallel

serial

AppleTalk Ethernet UARTSCC

binary

ASCIIASCII

seven

controlcharacters

low ASCII

high ASCII

alternate characterset graphics commandsextensions

ASCIInon-transparent

300,000,000

400$2

$2.50 $1.50

$3

CD ROM

INSPEC IEEE

FAX

SCSI

256

ASCII

128 32

3232

32

ASCII

MSB

MSB

ASCIIASCII

MIDI

Data Transmissionand Compression

Gaining Transparency

69.3

October, 1993

Fig. 3 – SOME TRANSPARENCY SCHEMES that let you send unrestrictedbinary data over a comm channel that reserves one or more ASCII codes.

Reserves another character such as an escapeor a " \". This "breakout" allows single problemcharacters to be sent as two non-problem ones.

Replaces problem characters as they occur withtheir four byte octal equivalent. Can becomeungainly if used too often.

Temporarily disables all special characters longenough for a fixed number of binary bytes to besent. A standard for BBS uploads.

Each binary byte is converted into a hex pair ofprinting ASCII characters. Doubles file size andtransmission times.

Each group of four binary bytes is converted intoa new group of five print-only ASCII characters.Increases file size by 20 percent.

The channel is replaced with a better one thathas no character reservations. Such as SCSI,EtherNet, AppleTalk, or other LAN systems.

Escape codes –

Octal definitions –

XMODEM comm –

Hex-ASCII pairs–

ASCII-85 coding–

True transparency –

Fig. 4 – HERE IS A SUMMARY of most of the more popular data compressionschemes in use today. All are fairly easy to explore on your own.

Replaces identical repeats with which byte torepeat how often. Used for black and white fontbitmaps. Otherwise limited. Lossless.

A variation on run length encoding for businessletters and other "large white area" uses. Alsoknown as the CCITT format. Lossless.

The standard used for disk compaction. Offers a2:1 to 3:1 reduction of most data forms. Noisesensitive because of low redundancy. Lossless.

Uses the Discrete Cosine Transform to offer lotsof compression for images and still video. Has"tiling" artifacts. Lossy.

JPEG is just the most popular form of the DCT.MPEG adds motion estimation and differencingfor movies and full motion video. Lossy.

An improvement on DCT that has fewer artifactsand computes faster with simpler hardware andfewer tiling artifacts. Lossy.

Front end intensive method that offers dramaticcompression ratios of 1000:1 and beyond. Bestfor CD ROM image distribution. Lossy.

A general purpose computing language thatuses extremely sparse data sets. Can greatlyreduce the size of all graphic data. Lossless.

Run length coding –

FAX compression–

LZW compression–

DCT compression–

JPEG and MPEG –

Wavelets –

Fractal math –

PostScript –

or other reserved character, you mayend up in deep trouble.

Instead, the newer and better datacomm systems are totallyand do not place any restrictions onthe meaning that any byte can have.Examples of transparent data commare , , and .

Many older comm systems allowonly non-transparent data. Which canmean you’ll have to pull some sneakytricks to send transparent data overthem. We call these

. Per figure three.Any trick that makes printing

characters look like unrestrictedand transparent binary codes is prettynear guaranteed to make your codelonger. But these tricks do let you useolder and standard comm.

One simple method is to use some. Here you use

an escape character or a reverse slashto let you change the meaning of asingle character. You could also usean where any problemcharacters get replaced with, say, areverse slash and the octal code of theproblem characters.

Since the octal codes are all digitsfrom , these can easily be routedover any non-transparent channel asprint-only characters. Ferinstance, a

should print out as a "•" bullet inmany systems.

Yet another trick is to temporarilymake the comm channel transparent.This is the way that and itsimproved offspring lets you uploadfull binary data to systems orover email. PostScript uses its

in a similar scheme. Totalcooperation of sender, sendee, and acomm channel is manditory.

A more general solution is called. When in hex format, each

binary byte gets broken down into ahigh 4-bit sub-byte plus a low 4-bitsub-byte. Each sub-byte should haveonly sixteen possible values. Thus, itcould be coded as the digits andthe letters and then sent out asprinting characters. For instance, theletter A is coded as or hexcoded as .

Hex format is easy and simple. Itsobvious penalty is that it thenumber of characters stored or sent.Everything takes twice as much roomand twice as long to send.

A more subtle route is . In

transparent

AppleTalk SCSI EtherNet

transparancyschemes

character substitution

octal notation

PostScript

binaryencodings

hex format

doubles

96256

0-7

\267

XMODEM

BBS

0-9A-F

ASCII $61$4641

ASCII-85

69.4

Hardware Hacker

MAGIC RESOURCES

1680 NE 123rd StreetNorth Miami, FL 33181(305) 891-7224

Rt 1, Box 113AMiddleburg, VA 22117(703) 687-6476

6765 El Banquero PlaceSan Diego, CA 92119(619) 287-3706

1002 Country Club PradoCoral Gables, FL 33134(305) 264-3321

45 West 34th Street #607New York, NY 10001(212) 279-6079

27 Bright RoadHatboro, PA 19040(215) 672-3344

PO Box 789Medford, MA 02155(617) 482-8749

6 West 32nd StreetNew York, NY 10001(212) 239-8383

5082 Lincoln AvenueChicago, IL 60625(312) 334-2855

1265 University DriveCoral Springs, FL 33071(305) 755-8586

734 N McKeever AvenueAzusa, CA 91702(818) 969-4519

62 Washington ManorWest Haven, CT 06516(203) 932-9586

PO Box 510260St Louis, MO 63151(314) 846-5659

3238 East DouglasWichita, KS 67208(316) 683-9582

Biscayne Magic

Collector’s Workshop

Cosmar Magic

Fantasio Magic Products

Flosso/Hornmann Magic Shop

Guaranteed Magic

Hank Lee’s Magic Factory

Louis Tannen, Inc

Magic, Inc

Magical Moments

Owen Magic Supreme

Patry Magic Productions

Society of American Magicians

Stevens Magic Emporium

, you group all your binarybytes by fours and let each group of

binary bytes be sent as a groupof printing characters. Only theprinting characters from throughare needed. In essence, you are usinga base-85 numbering system.

sounds horrible. And itlooks even worse on screen. But it isfairly simple to do and offers only a

percent transmission penalty for afull transparency.

You use whenyou want to shorten a message. So itwill store in less space, send in lesstime, or transmit over some narrowerbandwidth. There are two penaltiesfor data compression use. One is thattime and effort is needed to compressand uncompress. The second is that acompressed message inherently hasless redundancy. Any errors made oncompressed data are likely to do baddamage, some of it unfixable.

A third "feature" of compression isthat your information will no longerbe human readable.

There are many different types of

data compression which are populartoday. Each one has its strengths andweaknesses. Each one will work verywell for its intended use. And willperform poorly (even expanding!) forother uses. Some compressionschemes appear in figure four.

Any data compression scheme is if you could always get back what you started out with.

Obviously, electronic funds transferand computer programs must pick alossless compression. A compressionscheme is if you only get backroughly what you started with.

Ferinstance, that tapioca puddingscene in

: Your average couch potatowon’t spot a misplaced pixel or two.

Lossy data compression schemescan offer much higher compressionratios with a selected quality tradeoff.This is especially important in fullmotion video or sending over alimited channel bandwidth.

Let’s try to capture the flavor of afew compression schemes…

Run lengthencoding often works best with font

bitmaps and monochrome graphics. Itis lossless and is especially good ondata having long repeats of identicalcharacters. What happens is a stringof identical characters gets replacedwith codes for "repeat this characterthis many times".

This one is alsocalled format and is really avariation on the run length encoding.Also lossless. It is useful for sendingmonochrome documents with lots ofwhite space. Such as business letters.

This encoding is in general arather poor performer for other datatypes. See ap note from

for direct comparison of allmajor compression schemes. The titleis

.

The standardused for disk compaction. Short for

. A totally losslessscheme that usually offers a tocompression. This is error sensitivesince redundancy is removed.

Shorthand forthe . This islossy but gives high compression forpictures and still video images. Highquality compressions beyond aretypical. You can go beyond witha modest loss of image quality. Tendstowards objectional tiling artifacts.

is simplyanother name for the most popularversion of the , as is used by the

. Itis often best for still images that standalone. by the

is an extension ofthat allows significant squashing offull motion video and . It doesthis by overlaying and

.The results are impressive

and should lead to full length videoson and sending overstandard tv broadcast channels.

This is astunning improvement over thethat eliminates many visual artifacts,codes more compactly, offers highercompression, and can execute faster.One champion of this new technologyis . These folks do have lots ofreprints and ap notes available. Plususeful hardware and software.

fourfive

@ u

data compression

losslessexactly

lossy

Godzilla versus the NightNurses

Run length encoding–

FAX compression–

AdobeSystems

Supporting Data Compression inPostScript level II

LZW compression–

Lempel-Ziv-Welch

DCT compression–Direct Cosine Transform

JPEG and MPEG–

Joint Photographic Experts Group

Motion PicturesExpert Group

differencingmotion estimation

Wavelet compression–

Aware

ASCII-85

ASCII-85

20

HDTV

CCITT

FAX

#5115

2:1 3:1

10:130:1

JPEG

DCT

MPEGJPEG

HDTV

MPEG

CD-ROM HDTV

DCT

Fundamentals of Compression

69.5

October, 1993

NAMES AND NUMBERS

1585 Charleston RoadMountain View, CA 94039(800) 833-6687

One Memorial DriveCambridge, MA 02142(617) 577-1700

Box 999, K6-54-WattsRichland, WA 99352(509) 372-4274

5000 Arlington Center BlvdColumbus, OH 43220(800) 848-8199

3460 Hillview AveuePalo Alto, CA 94304(415) 858-2700

55 Green StreetClinton, MA 01510(508) 365-9150



PO Box 130Hornbrook, CA 96044(916) 475-3179

5550A Peachtree Pkwy #650Norcross, GA 30092(404) 840-0310

Hickory Corners RoadDalmatia, PA 17017(717) 758-8000

Rt 1, Box 1551Sautee, GA 30571(706) 865-5495

311 N Morgan StreetChicago, IL 60607(312) 829-1365

5700 NW Pacific Rim BlvdCamas, WA 98607(800) 642-0261

1823 Hummingbird CourtWest Richland, WA 99352(509) 967-5032


Adobe Systems

Aware, Inc

Batelle Pacific Northwest

CompuServe

Dialog Information Services

F-P Display Electronics

GEnie

Hewlett-Packard

Home Power

Iterated Systems

Mahantango Manor

John Reese

Roberts Electric

Sharp

Stirling Machine World

Synergetics

The fractalcompression is a unique and totallymaverick new approach. For certainimages, it offers compressions in the

to range. While a lotof front end effort is needed to squashan image, ordinary software can beused to quickly rebuild all theimages. Even as animation. Thisscheme gets particularly useful whenplacing scads of stand-alone visualimages on . The leader hereis .

See for a classicexample.

Few people realize thatthe PostScript language itself can be auniquely powerful data compressor.This happens because of the sparsedata sets used to create all PostScriptpage descriptions.

For instance, a scanned logo mightneed half a meg of file space done inthose primitive "cuneiform and claytablet" coding schemes used by early

and Mac graphic programs. A farhigher quality and faster executingversion of the same logo can often bedone in raw PostScript in as little as afew hundred bytes.

Compared to , typical pagesdone in PostScript end up much morecompact, transmit much faster, andoffer "camera-ready" typeset quality.I cannot fathom why anyone wouldever use for anything.

I certainly do not.Powerful new tools have recently

been added to PostScript to make itan even better data compressor. Theyinclude Adobe’s programand document system plusmy own triple distilling routines.

Much more on using these toolsappears in the

"red book".

I guess those are most of the mainmethods for data compression today.We have looked at many of these inmore depth in previous columns andthe reprints.

The obvious next question is howcan you go about…

Any old PostScript level II printerhas got built-in routines that letyou quickly and cheaply encode ordecode most compression schemes.Others are easily added. There’s also

support tools to bop back and forthbetween strings and files.

You can even layer one filter up ontop of another. As I’ve mentioned atime or three in the past, PostScript isan superb universal hacker’s generalpurpose computing language.

Which is by far your simplest andfastest way to get started doing yourown data compression work.

An example program for PostScript (or ) data compression is

shown you in figure five. This takes adisk based binary format image andthen encodes it. After that, thedata is made transparent by doing an

filtering.The results are fairly impressive.

What was a binary file or aHex file becomes a file that can besent over a non-transparent channel.You can even stuff your final fileinto a string to avoid a hard disk.

The differences in image qualityare quite hard to spot and are "goodenough" for pretty near any desktop

publishing use. Custom adjustmentscan be made for critical uses. Squashtime is a few seconds.

We have a few suitable test imagesup on if you can’t find yourown. Along with examples on how toquickly and simply do your own datacompression filtering. In particular,see files…

Plus, of course, and.

In several past issues and in those reprints, we have

seen how plain old car alternators canget converted into power steppers. Afew files on this topic also do appear

Fractal compression–

Iterated Systems

PostScript–

DistilleryAcrobat

PostScript ReferenceManual II

Hardware Hacker

filter Hardware Hacker

1000:1 10,000:1

CD-ROM

FRACTFERN.PS

PC

FAX

FAX

DCT JPEG

DCT

ASCII-85

49K 98K7K

7K

PSRT

LENA.PSHACK56.PSHACK69.PS

STR2FILE.PSLENAHIST.PSIMAGEKIT.PSMANDRILL.PS

STARTUP.PSSPEEDUP.PS

Doing Data Compression Alternators as Steppers

69.6

Hardware Hacker

Fig. 5 – THIS DCT COMPRESSED "LENA" IMAGE shows you how easy it isto do data compression in PostScript. Final transparent file size is 7K!

% DCT compress a file and then ASCII85 encode it…

/sourcefilename (lena.histo.1) def % name source file/targetfilename (lena.histo.dct.ascii85.1) def % name target file

sourcefilename (r) file /source exch def % open source file

targetfilename dup status pop pop pop pop % delete old targetdeletefilepop ifelse

targetfilename (w) file /target exch def % open target file

5 dict dup /DCTdict exch def begin % open work dictionary

save mark % start main loop

/Rows 192 def % height in pixels /Columns 256 def % width in pixels /Colors 1 def % one for b/w

/buf Columns Colors mul string def % open work buffer

target /ASCII85Encode filter /midtarget exch def % define filters midtarget DCTdict /DCTEncode filter /filtertarget exch def

Rows filtertarget source buf readstring pop % read-filter-write writestring repeat

filtertarget closefile % close files midtarget closefile target closefile

stopped handleerror if cleartomark restore % end main loop

end % close dictionary

on .A new "down homey" video is now

available that clearly shows you howto use car alternators as steppers. In a humongous automated sign routingmachine. In its spare time, the samebeast can create fancy and precision

parts for a weaving loom.Heddles and such. Doing everythingtotally homebrew at low cost.

The vid is and is availablefrom .

If the technology used is advancedenough, it looks like magic. And Iguess many Hardware Hackers see

themselves as being magicians of onesort of another. Only we largely usenew technology in place of the moretraditional deception, distraction, anddisorientation.

My favorite "magic" trick is to puta photocell beside a lightbulb in apositive feedback loop. You can then"light" your lamp with a match. Andthen blow the light out. On the firsttry, use a gentle puff. On the second,you puff harder. And, of course, onthe third try, you’ll cup your handsaround the lamp (blocking the opticalfeedback path) and big-bad-wolf it.

For our totally different resourcesidebar this month, I thought we just

might list a few of those hard-to-findmagazines and suppliers where realmagicians go to buy their wands, tophats, rabbits, and whatever. There’s alot of oddball stuff here.

From , a fat new. It

has displays and optocouplers,along with bar code stuff, fiber opticcomm, and robotic shaft encoders.From , a new bound collectionof on integratedcircuits, liquid crystal displays,components, and optoelectronics.

More information on Stirling heatengines appears in

, who also carry several booksand software items on this topic.

Michael Hackleman’s has become a

new feature section of. Plenty here on homebrew

electric vehicles.A good source of surplus hydraulic

parts is . Ultra largealphanumeric displays that use "flipdisk" technology are available from

.Classic phone parts and replicas

are offered by .Even in realquarter sawn oak.

A pair of unique and free productdevelopment resources are offered by

. One is the.

The other the list.

But do not contact anyone on thesecond list unless either your newproduct is already well into its thirdparty advanced beta testing stage, or

you are willing to pay the industrystandard development rates.

More on these topics also appearsin .

Speaking of which, I’ve gatheredall of my previous columns fromtogether into myreprints. Covers technical innovation,new resources, product development,self-publishing, and hackable newconcepts.

The usual reminder here that I’vegathered most of the stuff mentionedinto two sidebars,for the magician items, and

for everything else.Let’s hear from you.

Home PowerMagazine

Roberts Electric

F-P Electronics

Mahantango ManorFarmer’s Line Sets

Batelle Pacific NorthwestInventor Assistance Source Directory

Prototype DevelopmentAssistance Providers


Blatant Opportunist

Magic ResourcesNames

and Numbers

GEnie

John Reese

Hewlett-PackardOptoelectronic Designers Catalog

LED

SharpApplication Notes

Stirling MachineWorld

AlternativeTransportation News

PSRT

CAD/CAM

$19.50

RF

1907

(a)

(b)

ME

Magic Resources

New Tech Lit

Don Lancaster’s

November, 1993

Hardware HackerDigital photo imaging

Magnetic field resourcesFluxgate compass papersA pair of new GPS booksError diffusion techniques

70.1

Fig. 1 – A SPOTLESS HALFTONE from an unenhanced 300 DPI laser printedoriginal. With care, this new technique offers significantly better image qualitythan traditional methods. Results at 600 DPI are vastly superior.

Several readers have reportedproblems when logging on tomy board. Thetrick is simple: Be certain to

enter the after yourcomm software verifies a connection.You should then get prompted for anaccount number, and could proceedfrom there.

I have looked further at one of our"free energy" resources from a fewcolumns back. is one welldone labor-of-love operation. WhatRex has done is gather together hislifetime collection of weird science,junk science, pseudoscience, andutterly off-the-wall papers, patents,and press coverage. His typicalpackages might include full copies ofseveral patents and an article or two.There are hundreds of topics. All ofthem strange and wondrous.

This appears to be one of the finestpersonal collections of the technicallyweird anywhere. Stapled raw copiesare used to keep costs down. A freemaster list is offered.

Yawn. Stupendous breakthroughsare a thankless task, but somebodyhas to do them…

I’ve recently been exploring waysto improve digital photo quality. Forlaser, dot matrix, or inkjet printers.By going to a newtechnique that does non-obvious stuffin non-obvious ways, you can verymuch improve your print quality.

Stunningly so.Ferinstance, most "experts" would

agree that the "best" photo halftoneyou could do at a plain oldresolution is something like graysat spots per inch or grays atspots per inch. Which, at its verybest, will just barely miss ending up"sunday funnies" or "auto shopper"tabloid print quality.

Instead, figure one shows you aportion of a stock Lena digital photo,done using a brand new

halftone. This offers grays, agrain that seems much finer thanspots per inch, and full compatibility

with traditional ink.I’d dearly love to show you the

version, but we’d best not print ithere since the pressmight gag on a line screen. I willshow you where to get your own copyshortly, though.

The bottom line: You can nowprint your own "useful" photos at

and "very good" photos at. Photos for top quality Book-on-

demand publishing. And often morethan good enough to get rid of anyneed for high res typesetters.

To do so today does require somevery careful attention to detail and anunderstanding of just what is comingdown. But if you are willing to spendthe time and effort needed to learn

the basics, superb digital halftonescan be yours. What I thought I’d dohere is outline the secret insider toolsneeded for really great photos.

Traditional photography is often anextremely flexible and very forgivingprocess. If you don’t like what youhave, simply do some slopping in theslush to fix it. You can raise or lowerbrightness by opening up or closingdown a stop. Change the contrast byprinting one paper grade higher orlower. Or custom dodge out all yourmuddy grays and burn in your harshhighlights. Simple and easy.

Unfortunately, any digital halftonelacks this flexibility. Everything hasto be exactly and precisely on themoney. There is absolutely no room

GEnie

immediately

Rexearch

spotless halftone

spotless

PSRT

HHH

$6

300 DPI19

70 15 85

300DPI 65

106

600DPI

212

300DPI 600DPI

Electronics Now

Spotless halftones (!)

70.2

Hardware Hacker

Fig. 2 – TOOLS AND TECHNIQUES for superb digital halftones.

The original source material has to be first rate, including sampling of onepixel per pel to 64 or 256 gray levels.

Removes unneeded background info, focusing on the subject matteritself. Makes the subject relatively larger.

Makes each available gray work equally hard by redistributing the grayvalues in the image for best spread.

Linearizes the display to eliminate dot gain and similar effects. Matchesperceived to actual gray values.

Eliminates or minimizes gray steps by spreading the step error outamong several nearby pixels.

Combines the best features of dithering and halftones by usingrandomized multiple dots per cell.

Decent input data –

Cropping –

Histogram Equalization –

Gamma Correction –

Error Diffusion –

Spotless Haftones –

for forgiveness. Let’s look at some ofthe essential tools we now have toimprove digital halftones. We’ll alsosummarize these in figure two…

"Garbage in,garbage out" is especially true fordigital halftones. Unless you start offwith your best possible image data, adisaster is a certainty. Each , orpicture element in the original shouldcorrespond to pel in thefinal image. Those pel values mustget coded to at least andpreferably gray levels.

Oversampling or undersamplingcan lead to all sorts of glitches. Not tomention unnecessarily long file sizes.

There’s lots of tools available to dothe job. Such as . Ifyou are careful, photo enhancementcan instead be done by using thePostScript in your printer as a generalpurpose computing language.

This is just throwingaway outside areas that do not add toyour image content. Always get thekey theme or subject as obvious andas dominant as possible. But do keepyour aspect ratio something sane, like

or or . Others might endup visually jarring.

At any rate, the key point is to startoff with the very best image you can.And then enhance it using every trickin the book.

Withinlimits, the more gray levels you canprint, the better your results. If youonly have a few grays available, youcertainly do not want to ignore someof them. This can only make mattersworse. Too few grays give you a stepeffect having annoying visible jumpsbetween the gray levels.

Histo equalization can make eachpossible gray level equally important.To do an equalization, you plot theusage (or popularity) for every grayinto a . Then youyour gray levels so that each one getsused equally often.

Histo is for alldecent digital photos. Sadly, mostimage users have never even heard ofhisto. Or else refuse to spend the fewseconds needed to do this incredibleimprovement. Lots more on this in

and in those and reprints.

Most printersand some display devices are verynonlinear. They might favor whites or

blacks. Or extremes over mid range.Every effort must be made to make aprinter as linear as possible. Suchthings as engine technology, tonerdensity settings and paper choiceshelp a lot here.

The linearity plot is usually calleda . you have doneeverything else you possibly can toimprove your gamma, you may wantto selectively "throw away" certain ofyour gray levels, so the remaininggrays create the of a morelinear response. Thus you can tradeoff the total number of printing graysagainst the gamma for those grays.

Laser printers are notorious for a effect. A few details appear

in figure three. The first goal in anylaser printer is solid blacks. The blackpixels on the page are square, but thelaser spot is usually round. If you aregoing to completely cover a squarehole with a round peg, the peg has tobe larger. Each of these overlappingsegment quadrants creates a net dotgain of percent or more.

The net effect on any "black write"laser printer is to make surroundedblack pixels times in areathan desired, and any surroundedwhite pixels times thanusual. And possibly worse. What thisdoes is very strongly favor all yourblacks and deep grays. Ferinstance, a

percent gray that alternates whiteand black pixels can end up way ondown at a mere percent gray. Andthe "white write" systems will do theexact opposite.

Proper gamma correction is superimportant. So is picking halftoningthat avoids alternating pixels.

The big problemwith a limited number of grays is thatyou’ll get steps on any gray crossing,rather than a smooth gradient. At thecrossing, you have an error. An errorwhose difference is the gray you wantminus the gray you got.

A new technique known as takes the error you had and

then dribbles it out among severalfuture pixels. On even lines, you zeroout your current error and then addsome of your error to the next pixel tothe right, some to the next below andleft, some to the next below, and therest to next below and right. On oddlines, you lean to the left rather than

Decent input data –

pel

precisely one

linearly

Adobe Photoshop

Cropping –

Histogram equalization –

histo plot reassign

absolutely essential

HardwareHacker

Gamma correction –

gamma curve After

illusion

dot gain

larger

smaller

Error diffusion –

errordiffusion

64256

1:1 4:3 1.62:1

HACK56.PSBOD

14

1.56

0.44

50

22

70.3

November, 1993

Fig. 3 – LASER PRINTER DOT GAIN occurs whenever a round spot tries tocover a square pixel area. Dot gain creates a nonlinear gamma curve.

(A) Geometry of a round spot covering a square pixel.

requiredcoverageof 1.0 unit

pixel

0.14 north overlap

0.14 south overlap

0.14 east overlap0.14 west overlap

(C) A "black write" printer will favor the darker grays.

This isintended

to end up a50% gray

(B) A "white write" printer will favor the lighter grays.

This isintended

to end up a50% gray

to the right.Your net result is that any sharp

jumps can get replaced with diffusedblends. Instead of steps, you get afairly smooth gradient. Diffusion isbest used at higher resolutions.

If the steps end up very exact andrepeat over and over again vertically,you may get repeating artifacts. Thiscan happen if the error diffusion mathkeeps coming up with an identicalnumber sequence. To beat this, yousimply some noise to your dataso the numbers do not repeat. On a

level gray subject, you mightrandomly replace percent of yourgray values with a substitute valueof , , , or .

This is an example of noiseto make something look better! Thetrick here is that your added noise israndom and high in frequency. Thusit can be almost invisible. Purposelyadding noise can eliminate any lowfrequency artifacts.

Properly done error diffusion canmake artwork look like it wasdone on a premium phototypesetter ofmuch higher resolution.

Error diffusion is also very usefulfor blends and waterfalls inside oflarger typography. Any steps areespecially annoying here.

Error diffusion utilities appear on.

Any time youdo anything digitally, you’ll end upwith approximations. The samplingprocess inherently adds noise, givingyou both your intended signal andsome of one kind or another.Typically, these artifacts may appearas grainy dots. Or as distinct graysteps. Or as visual "bulldozer track"or "droput" artifacts.

O.K. We have noise in anydigital system. And we might evenwant to purposely more noise. Aswe’ve just seen, carefully added noisein a digital system can oftenyour final perceived signal to noiseratio! audio does it all the time.Now the trick here is simple:

.Certain types of noise look much

worse than others. Large repeatingspots are bad. Quantized gray levelsare bad. Anything that happens overand over again in a row or a column

is bad. Thus, we have "good noise"and "bad noise".

To optimize things, make your"good" noise…

• as random as possible• as uniform as possible• as consistent as possible• as far spread out as possible• as high a frequency as possible• as visually diagonal as possible

Let’s assume you have a square cell of dots that you can only turn

completely on or off. Which shouldgive gray levels, including blackand white. There are two traditionalmethods of converting this cell into a"gray" splotch on your page, called

and .With halftoning, you’ll create

black area in the middle of your celland let it "grow" as you go blacker.

Just the same as a traditional printer’shalftone dot. Your quantizing noisewill obviously be low frequency andwill repeat regularly.

The low frequencies and obviousrepetitions are just about thepossible types of noise you can havein your halftone.

In theory, a dithering can greatlyimprove on your noise artifacts. Withdithering, you create a pattern of thecorrect number of dots spread out asuniformly as you can inside your cell.You’ll end up with a very high noisefrequency and a more or less uniformnoise distribution. So, dithering can

give us lower noise andpleasing results.

Unfortunately, dithering has a fewnasty habits. If you’ve got dot gain,then the dithered patterns can end up

darker than you intended. The

add

adding

GEnie

Spotless halftones –

artifacts

must

add

raise

Makethe unavoidable noise work for you,rather than fight you

halftoning ditheringone

worst

theoretically

much

25615

5653 54 55 56 57

600 DPI

PSRT

CD

8 x8

65

70.4

Hardware Hacker

Fig. 4 – SOME NEW REFERENCES for fluxgate compasses.

Alan Phillips, ,Alexandria, VA, USA, p 145-150, 1993.

A. de Sa and K. Heron, , v 4 n 5,May 1993, p 633-634, ISSN: 0957-0233.

J. Peterson, et al, , v 3 n 12, Dec1992, p 1149-1154, ISSN: 0957-0233.

Pavel Ripka, , v 33 n 3, Jun 1992, p 129-141,ISSN: 0924-4247.

R. Dalpadado, , v 28 n 17, Aug 13 1992, p 1662-1663,ISSN: 0013-5194.

S. Kawahito, , p 1077-1080, ISBN: 0-87942-585-7.

S. Ghatak, , v 103 n 1-2,Jan 1992, p 81-85, ISSN: 0304-8853.

O. Nielsen, , v 2 n 5, May 1991,p 435-440, ISSN: 0957-0233.

Pavel Ripka, , v 83 n 1-3,Jan 1990, p 543-544, ISSN: 0304-8853.

Low cost dead reckoning sensors –

Three-axes fluxgate magnetometer with multiplexed sensors –

Ring core fluxgate sensor null feed-through signal –

Review of fluxgate sensors –

Bipolar magnetometer sensor similar to fluxgate device –

Micromachined solenoids for highly sensitive magnetic sensors –

Simple fluxgate magnetometer using amorphous alloys –

Analysis of a fluxgate magnetometer based on metallic glass –

Improved fluxgate for compasses and position sensors –

Institute of Navigation 1993 Tech Meeting Proceedings

Measurement Science & Technology


Sensors and Actuators

Electronics Letters

IEEE ’91: 91 Int Conf Solid State Sens Actuators

Journal of Magnetism and Magnetic Materials


Journal of Magnetism and Magnetic Materials

midrange gray level could end updown below deep gray if you arenot extra careful. You might end upwith a very bad gamma curve.

Note that that brand new or technology is simply a

variation on plain old dithering. Andjust like dithering, the dot gain can beexcessively high for toner based laserprinter apps.

Dithering can have annoying andquite obviously repeating artifacts,especially in large gray areas. Thesecan look just plain awful. Finally,dithering creates spots that are tinyby traditional printshop standards. Afully dithered halftone often canbe reproduced in ink!

What you do for spotless halftonesis take the best features of halftoning,error diffusion, and a good gammacorrection. Then combine them in anoptimum way that best obeys all our"good noise" rules above.

Let’s start with all those repeating

artifacts common to dithering. To getrid of these, you simply select one of

possible dither patterns for a givengray. You do this at random. A goodchoice for is usually eight. You dowant to make sure all of your selectedpatterns have their dots as far apartfrom each other as possible and thateach row and each column gets hit

the same number of times forthe entire pattern set.

Next, instead of using the "singledot" of a halftone or those "too manydots" of dithering, you pick only a

dots per cell. Use enough dots toraise your grain frequency but notenough to cause excessive dot gain.Eight dots per cell could be a usefulcompromise. You allow each of theseeight dots grow in the same manneras you would one halftone dot. Yourandomize "which dot grows how" tominimize long term repeats.

Finally, you throw away a few ofyour available grays to do a gammacorrection and balance the brightness.But note that your grays have to be

thrown away you do your histoequalization! Otherwise, some of thegrays will be more heavily used thanothers.

Spotless halftones can be based onimage masks, on patterns, or evendone as characters in a custom font.I’m still working on several of theseexciting new variations.

One possible result is apicture having the same

as a spot per inch halftone, uncorrected gray levels, and grain

equal to spots per inch. Exceptthat randomizing can make the graineven obvious. Any pelimage can end up around inchessquare at and a giantinches square at .

There are lots of options in thisemerging new technology.

Naturally, that PostScript generalpurpose hacker’s computer languageis absolutely ideal for exploring highquality digital photos. I’ve posted lotsmore on the spotless halftones to my

. Especially in our files and . We

also have great heaping bunches offiles on related imaging topics.

will give you that Lena I promised earlier.

There has been a lot of helplineinterest in measuring weak magneticfields lately. Perhaps you need anaccurate solid state digital compass.Or want to do some archaeologic sitemapping. Or lava tube cave hunting.Or are concerned about field safety.Or are trying to date an ancient pot,fireplace, or geological formation. Byapplying either or

tools.Magnetic field intensity is a

quantity that needs both an intensityand a direction. If you take a coil andrun a current through it, you will getan intensity of one if you use

ampere turns per inch.The earth’s magnetic field is even

weaker. Ferinstance, here in Arizona,the field is Gauss or so. It has a

degree and a degree.

For openers on all this, there’s an classic

paper by W. F. Stuart in

Crystalprint

not

n

n

exactly

few

before

informationcontent

less

GEnie

archaeomagnetismpaleomagnetism

vector

Gauss

inclinationdeclination

Earth’s Field MagnetometryReports on

256 x 2563.4

600 DPI 6.8300 DPI

PSRTSPOTLESS.PS RETOUCH.PS

SPOTLESS.PS600 DPI

2.02

0.2659 14

#32#22

"FM"

600 DPI

7564

212

The secret scoop

For more information

Low level magnetic fields

70.5

November, 1993

WEAK MAGNETIC FIELD RESOURCES

Anchorage Park EastroadPortsmouth Hants P03 5TDENGLAND



1814 Remell StreetFlint, MI 48503(313) 744-1330

859 Willamette StreetEugene, OR 97401(503) 343-1200

1800 Diagonal Rd, Ste 480Alexandria, VA 22314(703) 683-7101

110 Enterprise CenterMiddletown, RI 02842(401) 847-3327

Box 391Butler, PA 16003(412) 282-8282

11 W Spring StreetFreeport, IL 61032(815) 235-6600

2200 Lake Park DriveSmyrna, GA 30080(404) 436-1300

Langley Research CenterHampton, VA 23665(804) 865-3281

41 E 42nd Street Ste 921New York, NY 10017(212) 490-3999

PO Box 3409Sunnyvale, CA 94088(800) 447-1500

Box 5283Bloomington, IN 47407(812) 339-7305


1600 Feehanville DriveMount Prospect, IL 60056(708) 803-6100

PO Box 809066Dallas, TX 75380(800) 336-5236

Rockdale StreetWorcester, MA 01606(800) 962-4638

Autohelm

FW Bell

Dialog

Dinsmore Instrument

GPS World

Institute of Navigation

KVH Instruments

Magnetics, Inc

Micro Switch

Murata

NASA

NASA Tech Briefs

Phillips

Speleonics

Sprague

TDK

Texas Instruments

Walker Scientific

, , vol , p.. Essential reading.

A smaller magnetic measure is a. There are gammas in

a gauss. A one gamma sensitivity orbetter is desirable for archaeologicalmapping. A ten gamma sensivitity isneeded for a decent compass.

At first glance, there seem to befive schemes for measuring any weakmag fields. These are the ,those devices, the

, the and the . But the

fluxgate is ridiculously better thanthe others and is the one youshould really consider.

A compass is basically a magnet ona string. It twists around and pointsnorth. Problems include mechanicalmotions, very low sensitivity, and theability to only measure the directionof the field.

The is the transversecurrent produced in certain materialsin the presence of a magnetic field.Lower cost sources for Hall devicesinclude , ,and . These are great forworking with real magnets. But Halleffect devices lack the required lowfield sensitivity by a factor of ormore. And are thus forweak field measurement.

Er, with two minor exceptions. The people have combined a

traditional compass with hall sensorsfor a low cost device with a degreeresolution. Or degree res if youstack a pair of them. And the

folks now supply a huge andrather expensive Hall effect sensorassembly that theoretically could beused for a low res compass.

A proton precession magnetometeris just a bottle of distilled water witha coil around it. A strong current isrouted through the coil and then getssuddenly released. The mag fieldshift can cause a wobble in certainhydrogen atoms. A process known as

. The frequency ofthis precession is proportional only tothe magnetic field strength. But not toits direction. Typically, the frequencyis in the Hertz range and onlylasts for a few hundred cycles. At afew microvolts maximum. Accuratemeasurement here is not trivial.

An important proton magnetometerpaper showed up in the August

. Youmight also find

, , forApril , pages of value. Aswell as the

by A. J. Carrington; and by W.

Benjaman.A proton precession magnetometer

simply is not worth the hassle thesedays. Why? Because the upcomingfluxgate is both ridiculously simplerand offers better sensitivity.

The is an orphantechnology still kicking around for noapparent reason. This is a devicewhose resistance will change when amagnetic field gets applied. Sourcesinclude , , and .But their sensitivity is apallingly lowand they have nasty habits of needingexotic external magnetic biasing andsuddenly flipping without warning.

Avoid this turkey.The is by far the best of

the batch. Which is a saturable toroidcoil with two or three windings. It issimple, cheap, and offers outstandingsensitivity. Very hacker friendly toboot. A winding will wraparound the core. This will alternatelysaturate and unsaturate the core. The

winding goes the core.A second sense winding can be addedat right angles to the first for and

channels.In operation, the core permeability

gathers in the earth’s field when it isunsaturated and does nothing whensaturated. The gathering in and therelease of the field induces pulses inthe sense windings. These pulses areproportional to the strength and thedirection of the sensed mag field.

Sadly, I know of no cheap sourcefor a hacker fluxgate sensor.

Progress in Physics

gamma

compassHall effect proton

precession magnetometer mag-netoresistor fluxgate

only

Hall effect

Allegro Texas InstrumentsMicro Switch

totally useless

Dinsmore

F. W.Bell

Larmor precession

Review of Scientific InstrumentsIEEE Transactions on

Geoscience Electronics

Introduction to MagneticResonanceNuclear Magnetic Relaxation

magnetoresistor

Murata Philips

fluxgate

control

sense across

sinecosine

Radio

1972 35803-881

100,000

1000

4522.5

1300

1956

GE-9 #21971 99-103

TDK

70.6

Hardware Hacker

NAMES AND NUMBERS

6151 Powers Ferry Road NWAtlanta, GA 30339(404) 955-2500


1492 Highway 30Clarence, IA 52216(319) 452-3377

12856 Inglewood AvenueHawthorne, CA 90250(310) 679-1405



2000 Sierra Point ParkwayBrisbane, CA 94005(415) 589-8300

445 Hoes LanePiscataway, NJ 08855(908) 981-0060

201 Varick StreetNew York, NY 10014(212) 620-3371

2507 West Erie DriveTempe, AZ 85282(602) 431-0880

PO Box 20912Phoenix, AZ 85036(800) 521-6274

Rt 1, Box 1551Sautee, GA 30571(706) 865-5495

PO Box 19250Jean, NV 89019


PO Box 809066Dallas, TX 75380(800) 336-5236

585 North Mary AvenueSunnyvale, CA 94086(800) TRIMBLE

Access Control

Adobe Systems

ATV Today

Fast Proto

GEnie

Hewlett-Packard

Hitachi

IEEE

Information Dislpay

Metermaster

Motorola

John Rees

Rexearch

Synergetics

Texas Instruments

Trimble Navigation

has apparently dropped theirfluxgate car compass. Pricey units areavialable off the shelf from and

. You can make up yourown fluxgate sensor by starting offwith a core andusing a control winding of turnsof wire plus a pair of sine andcosine sense windings of turnsof wire. Additional details appearin the reprints.

Other sources for fluxgate detailsinclude ;a pair of articles in the Dec andJan issues of ;transactions , pages ;and various coverage in ,in that , and in

magazine.If you do know of a good hacker

fluxgate source or want to sell theseyourself, be sure to let me know. An

for your trouble.My story on archaeomagnetism

and paleomagnetism appeared in the

September issue of. Way back when.

Lower level magnetic field sensorsand instruments are available through

and .As with any technical subject, you

can instantly get up to date anywherein the world at any time of day byusing the .As we found out last month, Dialog isnewly available on a cash-and-carrybasis by way of either or

. About thirty cents per title.A quick Dialog dump disclosed the

recent fluxgate papers of figure four.I’ve tried to gather many of these

references into this month’s resourcesidebar.

By the way, if you’ve ever got anyancient "horses mouth" references inany field, all you have to do is use the

to pick upany later developments. Unlike mostresources this magic reference letsyou work in time, picking upnewer and newer material.

From , a. Plus a new

two inch thick from . About pages worth. A definitive tome

fer sure. From , the.

is an old-line supplierthat offers a wide variety of namebrand test gear from all of the majorsuppliers. A free page catalog.

There is now a brand new methodof using parallel ports that is bothvery high in speed and bidirectional.This major comm improvement is the

spec. More detailson the spec from the , while infoon Windows software drivers can befound through .

The folks havelong offered a great no-charge introbook titled

. They have just added a new title.

Differential offers sub meternav and position accuracy. Even ifyour military purposely fouls up thesatellite signals. The secret is to havea second nearby receiver in a fixedand known location.

Finding printed circuit resist inkfor plotting pens can be a real hassle.One costly supplier is . Afree if you can come up with aless outlandishly overpriced source.

is a new newsletter forAmateur Television industry insiders.

Our two obscure trade journals forthis month are , allabout mag stripe readers and such. Or

for lots on ,, and display technologies.

A reminder that a really great new video on rewinding your own

auto alternators for use aspower steppers is obtainable through

.For all the fundamentals of digital

integrated circuits, do check into my or .

Either by themselves or as a portionof my improved

. See my nearbyad for more info. Or send for a freebrochure.

As usual, I’ve gathered most of theitems mentioned into the

and thesidebars. Always check here first.

Shack

Autohelm

Magnetics

Hardware Hacker II

NASA Tech Brief

Sport Aviation

GPS WorldJournal of Navigation

Speleonics


ElectronicsWorld

F. W. Bell Walker Scientific

Dialog Information Service

CompuServeGEnie

Science Citations Index

forward

Motorola SemiconductorMaster Selection Guide

Linear Circuits DataBook Texas Instruments

Hitachi WirelessCommunication IC Summary

Metermaster

Boise

HP PeripheralsTrimble Navigation

GPS: A Guide to the NextUtilityDifferential GPS Explained

Fast Proto

ATV Today

Access Control

Information Display

John Rees

TTL Cookbook CMOS Cookbook

Lancaster ClassicsLibrary Synergetics

Names andNumbers Magnetic Resources

KVH

50086-2F143

#301000

#35

LAR1356081

82 IEEEMAG-8 #1 76-82

1969

1500

752

PC

IEEE.P1284

GPS

ISMM

LCDLED CRT

$19.50CAD/CAM

IEEE

New Tech Lit

Don Lancaster’s

December, 1993

Hardware HackerDigital Bogey contestMultimedia resources

CTCSS tone squelchingCoin mechanism sourcesLow distortion sinewaves

71.1

Fig. 1 – THE EIA-200-B CTCSS (Continuous Tone Controlled SubaudibleSquelch) tones can solve many hacker problems that require simultaneousvoice and data signaling over the same channel. These may be hardwire orserial programmed using the MX365A codes shown.

ToneFrequency

67.069.371.974.477.0

79.782.585.488.591.5

94.897.4

100.0103.5107.2

110.9114.8118.8123.0127.3

131.8136.5141.3146.2151.4

156.7162.2167.9173.8179.9

186.2192.8203.5210.7218.1

225.7233.6241.8250.3

no toneserial inputtest mode

D5(pin 5)

11010

10101

01000

00000

00000

00000

00000

0000

111

D4(pin 6)

11110

11101

11010

10101

01010

10101

01010

1010

101

D3(pin 7)

11111

11111

11111

11111

11100

00000

00000

0000

0data

0

D2(pin 8)

10111

11110

10111

00000

00011

11111

10000

0000

0clock

0

D1(pin 9)

10111

01011

01000

11110

00011

11000

01111

0000

0x1

D0(pin 10)

11101

10001

10100

11001

10011

00110

01100

1100

0x1

New hacking opportunities doseem to be emerging daily.Word has it that there arebunches of new aps coming

down over those video cameraviewers and their support chips. Suchas tiny oscilloscopes, interfaces,virtual reality lashups, stereo, andeven precision graticules.

Another exciting new area is called. This one is a sure fire

school paper or college thesis winner.In binary optics, zillions of plain oldopaque dots are carefully placed on aflat sheet. Binary optics can replaceexotic combinations of costly lenses.

Amazingly, at least one researcheris using nothing but PostScript and agrunt phototypesetter for his opticaldesigns. Cheaper optics willbe an important early use.

More on these two as they unfold.Meanwhile, let us look at an obscurestandard that has lots of nonobviousnew hacker uses…

I do get lots of helpline requestsfor schemes to let you route voice anddata over the same audio channel atthe same time. Interference free, ofcourse. You might want to do this tocontrol a multimedia slide show. Orfor selective calling on a multi-partyintercom. Or for remote robotics.

Or as a handicapped aide. Or homeautomation. Or as a monitor for analarm system. Or as some animationscript to get saved to a cassette tape.Or as an "I’ve got the answer!" gameor quiz response. Or to synchronizeeffects on a carnival ride. Or for useas a radio private calling feature.

Since any particular comm channelhas a well-defined bandwidth, thereare definite limits as to what you canand cannot do here. So, we’ll assumethat low data rates are usable.

Touch tones could get used, but allof those beeps and blorps might endup annoying. The touchtone chips areoffered by , ,or .

But those folks appear tohave a much better way. There is an

obscure mobile comm scheme called, and short for the

.The related standard is .

As figure one shows us, there are standard or nearly-standard tones

in the spec, ranging from Hertz upto Hertz. In their intended use,these tones are combined with voicemessages on any radio channel. Onlythose channels set up to decode theirselected tone can hear their message.

CRT

VGA3D

CD-ROM

CTCSS

EIA-220-B

39

67250.3

binary optics

Teltone Silicon SystemsRadio Shack

om

ContinuousTone Controlled Sub-audible Squelch

MX-C

Tone signaling

71.2

Hardware Hacker

Fig. 2 – TONE ENCODER using the MX365A.

1 2 3 4 5 6 7 8 9 10 11 12

24 23 22 21 20 19 18 17 16 15 14 13

+5V XTL XTL LD D5 D4 D3 D2 D1 D0 GND REF

TIN RXA TXA BIAS TXB RXB PTL RX OUT DET COM RXD

MX365A

nc nc

nc nc nc nc nc nc

tone selectswitches

(open = 1)

+5 vdc

68 pf 33 pf

1.0 MHz

1 Meg

0.1 F

0.47 F0.1 F 0.1 F

0.1 F

tone outputto transmitteror recorder

hp filteredaudio outputto transmitteror recorder

audioinput

µ

µµ µ

µ

Fig. 3 – TONE DECODER using the MX365A.

1 2 3 4 5 6 7 8 9 10 11 12

24 23 22 21 20 19 18 17 16 15 14 13

+5V XTL XTL LD D5 D4 D3 D2 D1 D0 GND REF

TIN RXA TXA BIAS TXB RXB PTL RX OUT DET COM RXD

MX365A

nc nc

nc nc ncnc

tone selectswitches

(open = 1)

+5 vdc

68 pf 33 pf

1.0 MHz

1 Meg

0.1 F

0.47 F 0.1 F

0.1 F

0.1 F820K

560K

1N4148

0.1 F

tone outputgoes low iftone present

gated audiooutput

audio fromreceiver

or recorder

+5 to listengnd to gate

µ

µ µ

µ

µ

µ

The tone frequencies are inthat most phone or mobile comm gearsharply attenuates audio belowHertz or so.

The is a typical chip thatcan be be used either as the encoderof Figure 2 or the decoder of Figure3. This circuit offers your choice ofhardwire programmable tones or aserial computer control. I’ve shown

the hardwire mode, using the codingof figure one.

The costs in singles.If you directly apply low frequency

signaling tones, any lower speech ormusic frequencies could interfere ontransmit. This bad scene is known as

. And you will hear the actualtones on receive.

To beat these problems, a special

digital high pass filter is included onchip. In the transmit mode, the filtergets rid of any low frequency audiothat could interfere with your tones.You run your input audio through thefilter and then combine the tones withthe filtered output.

Note that the encoder chip doescombine the tone output with the highpass filtered input audio. You have toexternally add these two together.

Use an op amp or a pair ofsumming resistors, or whatever. Thisexternal adjustment should give youthe most flexibility to adjust levels.

If any compression or an automaticlevel control gets used, it goesthe tone encoder, not after it.

The presence of tones causes yourdecode output pin to go low. Fornormal use, a low pin also turnsthe output audio. Pin is a

feature. Hold this pin at thepositive supply to provide continuoustone-independent audio.

There is also one really cute hackincluded in the encoder that can getrid of any during normalcomm. See the data sheet for details.

You’ll need several receiver chipsif you need several tones.

The tone frequencies are set by the Mhz crystal. Presumably, you

could lower your input clock to lowerall the available tones. Or to hit some"magic" frequency. This would endup as nonstandard, of course. But itwould let you up your audio qualityby way of an improved low frequencyresponse. And might make your toneseven more invisible.

Your maximum data rates wouldalso have to get sharply reduced forlower tone frequencies. Better figurearound tone cycles as a minimumsignaling interval. At Hertz, thiswould mean about one command persecond maximum.

You want a baud rate, you got it.One baud!

Use the lower tone frequencies forminimum audio interference. Use thehigher ones for faster signaling.

om offers several variationson their basic chips. The istransmit only. Their has abetter microprocessor serial interface.Their runs on a lower supplyof volts. A tone squelching and aspeech scrambling get combined intheir or the .

300

MX365A

MX365A $8

131318

1.000

3030

MX-CMX315A

MX265A

MX165B3.6

MX375 MX275

subaural

talk-off

not

before

onpush to

listen

squelch tails

71.3

December, 1993

Fig. 4 – AN ULTRA LOW DISTORTION 1 kHZ SINEWAVE GENERATOR.The pilot light acts as a stabilizing AGC loop in this elegantly simple circuit.

+

–

LT1037

sinewaveoutput

#327pilotlamp

1600

0.1 F

16000.1 mF

2

36

430 Ω

Ω

µ

Ω

What is multimedia? The term canmean just about anything to anybody.I’ll call this one

. Personally, at low cost, and onyour own desktop.

Two hot multimedia buzzwords are, which tells us that tv

sets, cable services, and telephonesare getting more like personal com-puters and vice versa. And

, which means that you’ll nolonger have to edit materials in theirtraditional " roll" order.

Newer Macs or that Amiga based do seem to be

running away with all the multimediamarbles these days. NewTek recentlyintroduced the , a small andcheap box that does the work ofnetworked Video Toasters.

Besides completely blowing awaysupercomputers and workstations attheir end game, this one ridiculouslyshortens the rendering time neededfor full animation sequences.

As our resource sidebar for thismonth, I have gathered together a fewof those magazines and other sourcesthat I have found personally useful tokeep up on multimedia happenings.The list is not complete, so please letme know more about your favoritemultimedia resources.

One thing that multimedia shouldeventually lead us to is…

The Screamer is only backing upfor a good start. Within a very fewyears, computers be smarter thanpeople. The time this will happen isarguable, but it definitely will occursomewhere between and

on April .Pacific standard time.Note that one gig is rapidly

approaching first silicon. As isfractal and wavelet compression.

At that point, we will routinely behandling both gigabytes of andterabytes of efficiently compressedand realtime accessed offlinestorage. All at low cost.

Sometime after that, all portions ofa multimedia experience could gethandled fully digitally. ina movie will consist of flexible andeasily manipulated data bases.

Everything will be a special effect.Live actors will, of course, be totallyunnecessary. As will the gaffers andgrips and Foleys. Or, for that matter,third assistant makeup advisor safetyconsultant best boys.

Given these stunning increases indesktop computing power, within twoor three decades at most, it should bepossible for one individual at home toproduce something comparable to afirst run movie. At a total cost of, say,

. Compared to the orso for today’s old-line flicks.

The primary video distribution, ofcourse, would be by way of

. With later releases through thoselibrary Teracubes, each of which canhold a decade or so of movies.

Naturally, the original script writerreceives the lion’s share of all incomegenerated. And the final product willbe what the script writer hadin mind.

I’ll call this inevitable happeningthe . As in Humphrey.A digital database should be able tototally define an actor’s personna ona pixel-by-pixel basis. Both at macroand micro levels. Just like we processwords and desktop publish today.

After teaching the data base all ofthe existing Bogey flicks, we simplyswitch to auto and let ‘er rip. Presto.

Zillions of brand new Bogey movies.For our contest this month, tell me

more about the new upcoming DigitalBogey. Show me in words orless what the consequences will befor a reduction in all thecosts of producing and distributing anentertainment experience comparableto a first run movie.

Among other things, we can expecta shift in smog levels in the basin.

types of smog.As usual, there’ll be a dozen or so

of my new books going to the better

entries, with an all expense paidThatcher, for twothat will go to the best of all.

Elegant simplicity is a theme thatwe do keep returning to over and overagain here, as it should be one of yourforemost hardware hacking goals.

Just as the can opener is by farthe finest invention of the twentiethcentury bar none, there are electroniccircuits which clearly do more withless. Using the bare minimum of partsto provide unexpectedly sophisticatedfinal results.

We’ve run many elegantly simplecircuits on these pages, but there isone clear cut winner which remainshead and shoulders above all of theothers put together. This, of course, isthat original audiosinewave generator.

The folks have

A-B

2:24 2:26AM 17, 1998

RAM1000:1

RAM

HDTV

$75 $75,000,000

175,000

1,000,000:1

LALA

(FOBAZ)

P-38

the use of computersfor control of high quality video andaudio

convergence

nonlinearediting

NewTek Video Toaster

Screamerforty

will

Everything

There will be no difference at allbetween actors and props!

Whichshould give us a one million to onereduction in the costs for producingmovie-like experiences.

InternetIV

exactly

Digital Bogey

All

Incredible Secret MoneyMachine II

tinaja quest

Hewlett Packard

Linear Technology

The Digital Bogey

Elegant simplicity again

Multimedia Resources

71.4

Hardware Hacker

MULTIMEDIA RESOURCES

445 Broad Hollow Road #21Melville, NY 11747(516) 845-2700

20525 Mariani Avenue 33GCupertino, CA 95014(800) 282-2732

462 Danbury RoadWilton, CT 06897(203) 761-1466




701 Westchester AvenueWhite Plains, NY 10604(914) 328-9157

12 West 21 StreetNew York, NY 10010(212) 691-8215

600 Community DriveManhassat, NY 11030(516) 365-4600

401 N Broad StreetPhiladelphia, PA 19108(215) 238-5300

21 Elm Street, 3rd FlCamden, ME 04843(207) 236-6267

7800 Merrimac AvenueNiles, IL 60714(708) 965-0566

155 Bovet Rd Suite 800San Mateo, CA 94402(800) 227-8365

14657 SW Teal Blvd Suite 119Beaverton, OR 97007(503) 579-4427

One Park AvenueNew York, NY 10016(212) 503-4433

901 Mariner’s Island Blvd, Ste 365San Mateo, CA 94404(415) 573-5170

Box 1289Gualala, CA 95444(707) 884-4413

215 SE 8th StreetTopeka, KS 66603(800) 765-3406

417 Bridgeport AvenueDevon, CT 06460(203) 877-1927

23410 Civic Center Way, Ste E-10Malibu, CA 90265(310) 456-2283

2 Dag Hammarskjold PlazaNew York, NY 10017(212) 371-0699

273 N Matilda AvenueSunnyvale, CA 94086(408) 252-0508


544 Second St, 3rd FloorSan Francisco, CA 94107(415) 904-0660

Advanced Imaging

Apple/APDA

CD-ROM Professional

Color Publishing

Computer Artist

Computer Graphics World

Computer Pictures

Computer Telephony

EE Times

Electronic Publishing

High Color

ImageBase

InfoWorld

Interactive Comm Society

MacWeek

New Media

New Media Insiders Report

NewTek

PC Presentations

Presentations

U&lc

Video Toaster User

Whole Earth Review

Wired

long had a ultra low noise opamp they are still real proud of. Thegain of million, offset ofvolts and common mode rejection of

decibels are all right up there inthe "adequate" range.

Beyond "fair to middlin".So, they naturally used the all-time

finest circuit anywhere ever in their

technical lit. This one gets shown infigure four. It is an ultra-pure 1 kHzsine wave generator. How pure? Lessthan distortion andpercent noise for a volt output.

The circuit is called aoscillator. Temporarily assume thatthe light bulb acts like an ordinaryresistor, providing a fixed gain of

for the opamp. Now, at precisely 1kHz, the series network will have

the impedance of the shuntnetwork, and both will offer the exactsame phase shift. So, you’ll have asinewave running around an op amphaving a gain of and a network thathas a loss of .

The feedback network can act as asingle pole highpass filter while thatshunt network acts as a single polelowpass filter. Should the frequencychange, the shifting impedance levelswill automatically return it to whereit belongs.

Leaving the right whereit’s at.

Now for the most elegant part. Thecircuit only works when that op amp

has a sinewave present and again of precisely . If your gain iseven a tad less than this value, theamplitude dies off. Slightly more, andyour amplitude keeps getting biggeruntil it distorts badly.

Obviously, for this circuit to workwe need some way of regulating thegain of the op amp. Set it above toget it started, and then continuouslyadjust things to stabilize your desiredamplitude. Naturally, you could dothis using an or

loop.Maybe an amplifier, a detector, and

some sort of fancy multiplier stage.Any aerospace engineer could comeup with a chip solution. If heis given a few technicians and enoughsimulation time on a mainframe.

Would you believe you can use aplain old light bulb instead?

An incandescent light bulb is anexample of a resistance. Ifthere is very little voltage across it,the resistance of the cold bulb staysfairly low. When the voltage acrossthe bulb (and the current through it)increases, the bulb warms up and theresistance increases.

The light bulb is a fully automatic,one piece circuit! On power up,it is a low resistance, and gives youenough gain to start oscillating. Atrun time, its resistance continuouslyadjusts itself to give you a constantand low distortion output.

The thermal inertia of your lampguarantees that all the variationsshould stay long term only, instead ofdistorting the output waveform.

Which gives you elegant simplicity

LT1037

20 25

1170.0025% 0.001%

6 RMS

+3

RCRC

31/3

3.0

3

AGC

10 $500

AGC

AGC

micro

Wein Bridge

twice

status quo

already

automatic gaincontrol

nonlinear

71.5

December, 1993

NAMES AND NUMBERS

221 Yesler WaySeattle, WA 98104(206) 233-9460

10273 NW 53rd StreetFt Lauderdale, FL 33351(800) 741-9840

601 Linden PlaceEvanston, IL 60202(708) 475-8440

PO Box 803Fort Atkinson, WI 53538(414) 563-6388

PO Box 129Vancouver, WA 98666(800) 637-2256

10 South Main StreetPennington, NJ 08534(609) 737-1902

PO Box 328Lancaster, PA 17603(717) 392-0733

3130 S Harbor Blvd Suite 330Santa Ana, CA 92704(800) 854-7179

18 Canal StreetBristol, PA 19007(215) 788-5583

PO Box 328Lancaster, PA 17603(717) 392-0733

Box 12685Lake Park, FL 33403(407) 848-8236


921 East 222nd StreetEuclid, OH 44123(216) 731-8375

4800 Bethania Station RoadWinston-Salem, NC 27105(800) 638-5577

PO Box 1241San Bruno, CA 94066(415) 359-0432

704 E DouglasWichita, KS 67202(316) 263-3241

PO Box 24970New Orleans, LA 70184(504) 488-7003

22157 Clarendon St Box 2550Woodland Hills, CA 91365(818) 347-3820

23191 Peralta DriveLaguna Hills, CA 92653(800) 775-5668

14351 Myford RoadTustin, CA 92680(714) 731-7110


22121 20th Avenue SEBothell, WA 98021(800) 426-3926

Always Jukin’

American Changer

American Science & Surplus

Automatic Merchandiser

Disability Bookshop

Electrochemical Society

Gas Engine Magazine

Global Engineering Documents

Herbach & Rademan

Iron-Men Album

Marlin Jones

Linear Technology

Lutech

MX-Com

Phaedra

Player Piano

Play Meter

RePlay

Shear-Loc

Silicon Systems

Synergetics

Teltone

at its very finest.Both networks must be very

carefully matched. Preferably betterthan one percent. That is a stockpilot light usually rated at voltsand milliamperes.

As a second contest this month, tellme about your favorite example ofelegant simplicity. Concepts similarto this superb sinewave oscillator, a

can opener, or a vortex cooler.Let’s hear from you.

I have recently gotten bunches ofrequests for low cost sources of videogame coin mechanisms. As surplus,these are largely catch-as-catch can.But ,

, and ,sometimes stock these.

For larger quantities, try the ads in, or the

. For antique versions,try the or theads in magazine.

and aretwo sources for the dollar bill changermechanisms.

If you come up with other sourceshere, please let me know.

is agood source for info on new batterytechnology, fuel cells, electroplating,corrosion, conductive polymers, andeven Buckeyballs. They publish their

magazine and hold lots oftrade conferences.

The third edition of the

is offered by . Authored byDavid Blevins and priced at .This is a combined Thomas Registryand Michlein Guide to the field. Ofthe resources listed, at least oneof them puts their moneywhere their mouth is – one milliondollars cash to anyone who is able toprovide some evidence of either

or aliens.A fine selection of books and other

handicapped resources is found at the.

Free samples of socket head capsare available from . Theseinstantly convert plain old cap screwsinto knurled knobs or thumbscrews,rosette grips, or tee-handles. Only abench vise is needed for assembly.

You can quickly and convenientlyget copies of just about any technicalstandard from

. But note that it is oftenmuch cheaper to go directly to thestandards associations themselves.We saw a full listing of these back in

and in my online and hard copy reprints.

Two rather strange and wondrouspublications for this month are the

and . Forrestorers of antique steam and gas

powered tractors respectively.If you want to start up your own

tech venture, be sure to get a copy ofmy newly revised

. Check my nearby ad for more info. Or send

for a free brochure.As usual, I’ve gathered most of the

items mentioned into the and

sidebars. Always check these beforecalling our voice helpline.

Let’s hear from you

RC

32728

40

P38

$19.50

400+(AI-TRAD)

UFO’s

Marlin Jones American Science& Surplus Herbach & Rademan

RePlay Playmeter AutomaticMerchandiser

Player Piano CompanyAlways Jukin’

Lutech American Changer

The Electrochemical Society

Interface

Almanac of Organizations and Publications

Phaedra

solid

Disability Bookshop

Shear-Loc

Global EngineeringDocuments

Hardware Hacker

Iron-Man Album Gas Engine

Incredible SecretMoney Machine IISynergetics

Names andNumbers Multimedia Resources

UFO

#47

Coin changers

New tech lit

71.6

Hardware Hacker

Don Lancaster’s

January, 1994

Hardware HackerHacker’s data exchangeAdobe’s Acrobat systemNew pseudoscience magVoice messaging circuitsSpecial effects resources

72.1

Fig. 1 – PLAYBACK-ONLY CIRCUIT for the Radio Shack 276-1325 voicerecorder. The ISD chip uses innovative on-chip analog data storage.

1 2 3 4 5 6 7 8 9 10 11 12 13 14

28 27 26 25 24 23 22 21 20 19 18 17 16 15

A0 A1 A2 A3 A4 A5 NC NC A6 A7 AUX GND GND SP+

+5D REC CLK EOM PD CE NC OUT IN AGC MIC MIC +5A SP-

ISD1000A

nc nc nc

ncncncncncncnc

play

10

8 speaker

+5 vdc

Ω

Ω

Let’s start off with a reminderthat a superb video on usingcar alternators for low cost,high power stepper motors

for and whatever is nowavailable from . Included isa demo of his sign routing system andstep-by-step rewinding details. Costof the vid is .

One hardware hacking topic whichsure has generated more than its shareof helpline calls lately involves…

At one time, analog tape cassettesseemed the only reasonable way torecord and play voice messages. Butthese days, we’ve got compact, lowpower, and reliable total electronicsolutions. Solutions which require nomechanical parts or moving media.

Uses? Everything from voice emailsystems to robotics to museum stuffto radio commercials to talking cards.

There are a lot of different optionshere. Options that trade quality andmessage time against costs, ease ofrecording, and compressibility.

Many older systems are based on or speech chips.

These systems are basically anconverter for recording, some digitalstorage, and output analog soundprocessing circuits for playback. Thedigital storage could get permanentlyburned into certain chips as orelse easily changed as external .But your usual route is to use a large

for messages that are only tobe changed every now and then.

Typical lower cost hacker systemshere are the from

and various offerings by. Pricing is in the

to range. These are usually asmall circuit board holding a speechchip, a message , some analogcircuits, and an output amplifier.

Everything from telephone up to quality is available by changing

the sample rates. But your memoryneeds get out of hand for messageslonger than a minute or so.

Two good starting points for thisapproach are the

data book from and various databooks and ap-notes from .

But there is a new kid on the blockthat offers a true single chip solutionto electronic messaging. This one iscalled , short for

. Instead of goingthe to digital storage back toroute, this new technique uses specialcircuitry that storessamples in a nonvolatile array.

The pioneer here is an outfit called. Short for

. Their current offerings arethe family that gives up tosecond playback at selected qualitylevels. As many as several hundreddifferent messages can be stored. Youcould easily record a vocabulary ofwords and combine them as neededunder external computer control.

Their analog storage capability is, or just under half a meg. But do

note that this is equivalent to manymegabytes of pure digital storage.

has also released a simpler andolder chip through

. This one costs around forthe chip alone and stashesanalog speech samples.

You will have to work up your owncircuitry around it. Our figure one

shows an ultra simple playback-onlycircuit, while figure two shows youwhat is needed to record and playback your own messages.

There is no reason why you can’talso use this for tones, sound effects,or short music. But note that thelower sampling rates of theirsystem pretty much will limit you totelephone quality.

Wouldn’t it be nice if you couldalways get printed circuitlayout artwork for popular magazineconstruction projects? With ongoingupdates and corrections long after thestory appeared in print? Or instant,low cost reprints for any tech articlefrom anywhere? Reprints that look asgood or better than the original? Orready-to-use panel art, dialplates, orlayout templates?

Well, I’ve been doing this for yearswith all of my more recent

, , ,and columns. Byway of my . Plus lots ofobscure stuff of mine which ispublished on line.

But that is just me.The key question here is: Which

CAD/CAM

$19.50

A/D

D/A

ROMRAM

EPROM

$20 $40

EPROM

CD

DAST

A/D D/A

ISD2500 90

480K

ISDISD1000A

$20128,000

DAST

PSRT

John Rees

Toshiba

Quik Voice EletechElectronicsMing Engineering

Voice Synthesis LSI

OKIToshiba

Direct AnalogStorage Technology

directly analog

Information StorageDevices

RadioShack

exact sized

HardwareHacker Ask the Guru Resource Bin

Blatant OpportunistGEnie

onlyOKI

ISDVoice Messaging

A Hacker Data Format

72.2

Hardware Hacker

Fig. 2 – A MULTI-MESSAGE COMBINATION playback and record circuitusing the ISD1000A. An electret style microphone is shown.

1 2 3 4 5 6 7 8 9 10 11 12 13 14

28 27 26 25 24 23 22 21 20 19 18 17 16 15

A0 A1 A2 A3 A4 A5 NC NC A6 A7 AUX GND GND SP+

+5D REC CLK EOM PD CE NC OUT IN AGC MIC MIC +5A SP-

ISD1000A

nc nc nc

ncnc

10

8 speaker

0.220.22 22 F

0.1 F

0.1 F

1 F+

address select

+5 v

+5 v

+5 v

470K4.7 F

2.2K

+5v+5v

2.2K

47K(typ)

2.2K

mic

enableresetrecord

+5v

2.2K

+5v

+22 F

Ω

Ω

µµ µ

µ

µ

µ

µ

µ

data format could be used so thatauthors of technical mags couldprovide the same service?

There are several obvious goals forsuch a data format. The files shouldbe totally device independent. Thevery same file should run identicallyon personal computer, Mac, ,

, Amiga, Sun, or Cray. The filesshould consist of ordinary printable

characters that can be sent overa non-transparent 7-bit data channel.There should be absolutely needfor any special end user hardware orsoftware. Files should be publishableon any and all popular printers.

The files should be more or lesshuman readable and easy to edit. Noroyalties, costly software, limits, uselicenses, or other restrictions shouldbe involved. No trace should remainof any of the proprietary code used togenerate the actual text and graphicimages. All the files should also lend

themselves to fullpublishing.

And, of course, the files should allbe super compact and run quite fast.Self-collating at the max possiblemechanical feed speed of the printer.With setup time. A reasonablegoal is per camera-ready page.

Uncompressed.We’ll assume that you are mostly

interested in a publication.And getting superb quality copies ofsomething into the hands of lots ofpeople. Simply and cheaply.

After working on this problem forseveral years, I’ve concluded thereare three routes to the hacker dataformat that seem reasonable. Theseare , , or Adobe’s new

document system.I don’t like at all. I never use

it. Special costly equipment is oftenneeded. Compared to camera-readyPostScript, quality is . The

exact size is never guaranteed. Andmost fax files end up much longerand transmit much more slowly.

It turns out that compressionis just about the possible wayto squash photos or fancy technicalillustrations. See Adobe’s notefor unbiased comparisons. And it isstill fairly tricky to store, edit, andreuse code. And there’s usuallyblack and white only.

Yet, there are lots of others nowoffering tech info via automaticservices. For instance,has some outstanding free resourceinfo on self-publishing available byway of his auto . And most of theelectronic trade journals now havelots of auto ads showing up.

On the other hand, PostScript canmeet all of these hacker data goals.As I have mentioned a time or twobefore, I use PostScript as a totally

computer language.I use it for everything from formalengineering design to stock marketanalysis. Plus, of course, dirtying upotherwise clean sheets of paper.

More and more hackers already dohave easy access to a PostScript laserprinter. If you do not, theshareware is widely available for thedownloading. This lets you run a fakePostScript over any popular printer,plotter, or phototypesetter. And yes,the full GhostScript source code isincluded so you can work from anyrecent host computer system.

One subtle but super importantfeature of PostScript: You can easilydo . Which can let youprecisely adjust your final size onprinted circuit art, compensating forpaper stretch or mechanical feedingerrors. PostScript, of course, worksbeautifully with the new direct tonerprinted circuit processes offered by

and . And,yes, PostScript could get convertedback into into older and more klutzy

or vector formats.Adobe Acrobat is brand new. This

is intended to let Fortune firmsachieve "paperless offices," whateverthose are. Their fancy document filesinclude global searching, nonlinearHypercard access, and thumbnailsketches for each page. The system isquite expensive.

Sadly, Acrobat document files can be printed without special viewer

IBMC-64

ASCII

10K

FAX

FAX

FAX

#5115

FAX

FAX

FAX

FAX

HPGL

500

allall

any

zero

Book-on-demand

zero

one way

PostScriptAcrobat

putrid

worst

Dan Poynter

general purpose

GhostScript

microsizing

DynaArt Designs Techniks

Gerber

not

FAX

72.3

January, 1994

Fig. 3 – TYPICAL ADOBE ACROBAT OUTPUT used to distribute high qualitytext and graphic documents. A special reader is needed at print time.

/F8 1 Tf9.75 0 0 9.75 60 427.5 Tm0.029 Tc0.032 Tw(The tone frequencies are)Tj/F9 1 Tf10.9 0 Td(subaural)Tj/F8 1 Tf3.7 0 Td( in)Tj-14.7 Te0.021 Tc-0.013 Tw(that most phone or mobile comm gear)Tj0 Te0.043 Tc0.115 Tw(sharply attenuates audio below)Tj9 0 0 9 200.4 406.5 Tm0.046 Tc0.124 Tw(300)Tj9.75 0 0 9.75 215.2 406.5 Tm-15.9 Te0.026 Tc0.016 Tw(Hertz or so.)Tj1.025 Te0.030 Tc0.038 Tw(The)Tj9 0 0 9 89.1 385.5 Tm0.032 Tc0.041 Tw(MX365A)Tj9.75 0 0 9.75 125.4 385.5 Tm0.030 Tc0.038 Tw( is a typical chip that)Tj-6.7 Te0.032 Tc0.053 Tw(can be be used either as the encoder)Tj0 Te0.032 Tc0.053 Tw(of Figure 2 or the decoder of Figure)Tj0 Te0.035 Tc0.068 Tw(3. This circuit offers your choice of)Tj0 Te0.048 Tc 0.148 Tw(hardwire programmable tones or a)Tj0 Te0.038 Tc 0.084 Tw(serial computer control. I’ve shown)Tj

Fig. 4 – TRIPLE DISTILLING can make the Acrobat output faster, shorter, andmore hacker friendly. No expensive software or special printer is required.

/Times-Roman 9.75 ss .31 .29(The tone frequencies are)60 427.5 hH ( in)203.9 427.5 H -.13 .21(that most phone or mobile comm gear)60 417 h 1.12 .42(sharply attenuates audio below)60 406.5 h .16 .26(Hertz or so.)60 396 h .38 .3(The)70 385.5 hH ( is a typical chip that)125.4 385.5 H .52 .32(can be be used either as the encoder)60 375 hH (of Figure 2 or the decoder of Figure)60 364.5 H .67 .35(3. This circuit offers your choice of)60 354 h 1.45 .47(hardwire programmable tones or a)60 343.5 h .82 .37(serial computer control. I’ve shown)60 333 h

/Times-Italic 9.75 ss .31 .29(subaural)166.9 427.5 h

/Times-Roman 9 ss 1.12 .42(300)200.5 406.5 h .38 .3(MX365A)89.2 385.5 h

software. Acrobat files pretty muchdemand the use of genuine PostScriptlevel 2. The final files are also muchlarger and run much more slowly thanis really necessary.

Because nearly all of those morepowerful PostScript commands aredisallowed in the files, some simplegraphic constructs will often generateunbearably long code. Ferinstance, acircle needs hundreds of bytes.

Something vastly better is clearlyneeded for a hacker file interchangestandard.

Why not combine the best featuresof PostScript and Acrobat? Acrobatdoes contain a useable but grievouslyflawed which can take anyPostScript input from any source andreduce it to only those essential corecommands. Usually (but not always)in a fairly efficient manner.

Sadly, the new distillery does all ofits work in the host, rather than theprinter. Any selected fonts must beavailable in host format. The file also has to be in one humongous piece,since persistent downloads andsupport are appallingly absent.

Nonetheless, the distillery is thekey to converting any code that wasgenerated on a proprietary ,pagemaking, or illustration programand converting it into license-free androyalty-free distribution format.

Each page appears in the Acrobatdocument as an . It is very easy to extract each page object, add somesimple header code, and make it intoa stand-alone PostScript file.

But I do feel that raw Acrobat pageoutput is much too long and runs fartoo slow. It is also hard to read andharder yet to edit.

So, I have come up with a process that dramatically

improves extracted Acrobat files. Thefiles are first split into their graphicsand text portions. Then the graphicportions are shortened and simplifiedby permitting additional PostScriptcommands. The tricks used here willdepend quite a bit on how the originalcode was first generated. But suchoperators as , , and

can play a big role here.The text is sorted so that

. And definedsuch that

CAD/CAM

distillery

run

object

tripledistilling

repeat translatearcto

each fontsize only gets used once

each text line stands on its

The Solution?

72.4

Hardware Hacker

SPECIAL EFFECTS RESOURCES

5-49 49th AvenueLong Island City, NY 11101(718) 361-8373

14141 Covello Street Suite 6AVan Nuys, CA 91405(818) 782-9833

Box 20027Riverside, CA 92516(909) 781-1917

13120-B Saticoy StreetNorth Hollywood, CA 91605(818) 765-4995

Box 815Wauconda, IL 60084(708) 526-2136

24307 Magic Mtn Pkwy #272Valencia, CA 91355

8455 Beverly Blvd Suite 508Los Angeles, CA 90048(213) 653-8053

132 Ninth StreetSan Francisco, CA 94103(415) 863-9684

11200 Montgomery, Suite 8Albuquerque, NM 87111(505) 263-5949

7110 Laurel Canyon Blvd Bldg ENorth Hollywood, CA 91605(818) 982-1483

74 Leonard Wood DriveBattle Creek, MI 49015(800) 357-2777

300 Canal StreetLawrence, MA 01840(508) 686-2964

Box 384Lebanon, NJ 08833(908) 534-5990

85 Old Kings Hwy NorthDarien, CT 06820(203) 656-3100

1000 Valley RoadGillette, NJ 07933(908) 647-5800

543 W. 100 North, Suite 3Bountiful, UT 84010(801) 298-9762

14201 Bessemer StreetVan Nuys, CA 94101(818) 902-9354

723 N Victory BlvdBurbank, CA 91502(818) 562-6548

Alcone Company

Cinefex

Cinema FX

Du-Bro Products

Electropea

Film & Video

Kryolan

Kuper Controls

Makeup & Effects Lab

Mannetron

National Hair Technologies

Polytek Development

Quantel, Inc.

Smooth-On

Special Effects Supply Co

Mat Sweeney

Sword & Stone

. Unneeded characters (such asleading zeros, trailing spaces, andextra precision) are also eliminated tofurther shorten the files. The amountof speed and size gain here can bevery impressive.

So much so that antriple distilled file is often shorterthan a compressed Acrobat file!

With some care, triple distillingcan leave you with level 1 commandsonly, so that older PostScript printerscan still be used. This will continueto be an important hacker feature forthe next several years or so.

Figure two shows you a fragmentof Acrobat text output, while figurethree shows you the double distilledresults. The Acrobat code is typically

longer and slower. Besidesbeing harder to read and edit.

Since many casual PostScript usersend up horribly baud rate limitingthemselves, a length penalty canalso become a speed penalty.

More details inThe triple distilling process can be

fully reversable. The end user couldalways use the Acrobat distillery toget themselves right back where it allstarted. Or to import into packagesthat only accept limited PostScriptcommands. Such use would normallybe very rare.

Custom or exotic fonts could gethandled one of five ways: You canignore them and default to .

You can ask your end user to get

all of his own fonts. If only a fewcharacters are involved, you can use a

that substitutes theactual font paths. This is great forlogos. See .

You could usefonts for a lookalike approximation.Or, You can internally tow along acopy of the needed font.

Yes, much of the triple distillingprocess can be fully automated.

If you do not have any access toAcrobat, there’s an olderfile available for the downloading.This older program has lots of bugsthat trash out clipping, scaling, andsubscripting. But it can be run in anyPostScript printer or emulator. It alsosupports persistent downloads, allowsrun commands, and has no host fontrestrictions.

I strongly feel that triple distilledPostScript is the ultimate solution fora compact and low cost hacker fileinterchange. I’ve got scads more onthis up on , including lotsof source code and examples.

Naturally, I’d be most happy tohelp you create your own distributionfiles in hacker data format. You cancall or write for help on this.

As the first of our two contests thismonth, just tell me your thoughts fora new hacker data format standard.There’ll be all of the usual

books goingto the best dozen or so entries, withan all expense paid Thatcher,

for two going to thevery best of all.

As usual, send your written entriesdirectly to me here at andnot to editorial.

How would you like to build yourown T-Rex? Or shoot your customversion of

as a home video? What you’llrequire for this, of course, are

. As you might guess, there is alow profile and little known specialeffects industry. Who can supply allof your needed bits and pieces. Eitheroff-the-shelf or custom.

The special effects supply sourcescan be a treasure trove for hardwarehacking. Included are materials forplastic, rubber, and resin molding.

65% 43%

65%65%

SPEEDUP.PS.

(1)

(2)

(3)

FONTELIM.PS(4)

(5)

DISTILL.PS

PSRT

(FOBAZ)

own

uncompressed

Courier

font eliminator

multiple master

GEnie


tinaja quest

Synergetics

Godzilla versus the NightNurses

special effects

Two Contests

Special Effects

Electronics Now

72.5

January, 1994

NAMES AND NUMBERS


11 West 42nd Street, 13th FloorNew York, NY 10036(212) 642-4900


3535 Stillmeadow LaneLancaster, CA 93536(805) 943-4746

16019 Kaplan AvenueIndustry, CA 91744(818) 333-6394

401 North Washington StreetRockville, MD 20850(800) 638-9636

83 Gerber RoadS Windsor, CT 06074(203) 644-1551

18955 SW BlantonAloha, OR 97007(503) 649-0837

2841 Junction Avenue, Ste 204San Jose, CA 95134(408) 428-1400

17921 Rowland StreetCity of Industry, CA 91748(818) 912-9469

785 North Mary AvenueSunnyvale, CA 94086(800) 832-6654

4 Nevada DriveLake Success, NY 11042(800) 446-5260

PO Box 4232Santa Barbara, CA 93140(800) PARAPUB

Route 1 Box 1551Sautee, GA 30571(706) 865-5495

PO Box 703Buffalo, NY 14226(716) 636-1425

Box 180562Austin, TX 78718(512) 339-6229


45 J Ringo RoadRingoes, NJ 08551(908) 788-8249

1220 Midas WaySunnyvale, CA 94066(800) 321-1718

PO Box 5185Mesa, AZ 85211

Adobe Acrobat System

Am. Natl. Standards Institute

Borderlands

DynaArt Designs

Eletech Electronics

GEnie

Gerber Scientific

Stan Griffiths

Information Storage Devices

Ming Engineering

OKI

Olympus Industrial

Dan Poynter

John Rees

Skeptical Inquirer

Sound Practices

Synergetics

Techniks

Toshiba

Untapped Technology Review

Special hardware. Unusual materials.Claymation supplies. Fur and hair.Armatures. Control cables. Remotecontrols. Unusual lighting. Fog andsmoke. And lots more.

As our sidebar for this month, Ithought we’d gather together a few ofthe better special effects resources.The center of the industry appears tobe a great quarterly magazine called

. A recent issue showed theinsider secret plans to all the Jurassicdinos, as well as the Andean planecrash. A second useful mag here is

.Two of the more intriguing entries

on our list are the and. The first

for medieval armor, and the secondfor fake fur and strange wigs.

There are a lot more where thesecame from, so be sure to let me knowyour favorites. Or anyone I missed.

In fact, let’s make a second contestout of it.

isa new labor-of-love pseudosciencejournal. Uh, this one seems midwaybetween the andand the .

Included are commented criticalreviews of some popular free energyand antigravity schemes, the currentcontents for the other pseudosciencemags, and off-the-wall patent listings.

A brand new book on buying andusing older oscilloscopes istitled

. This one costs from .

has just introduced their systems. This is a

full color video camera ain diameter at the end of a footstrobe-illuminated and fully steerablesnake-like probe.

While this dude looks outrageouslyexpensive, it just might make a reallydandy cave survey and explorationtool. Especially if it could be madeself-cleaning and waterproof to adepth of twenty feet.

The horse’s mouth source info on disk comm is known as

and is available fordirectly from the

is a hands-on magthat concentrates on tube audio using

only high voltage linear triodes. Thepreferred tube these days seems to bethe . To me, that mythical "tubesound" is simply so much hum, noise,and distortion added to an otherwiseclean audio channel.

You can easily pick up any amountof hum, noise, and distortion by usinga digital signal processing chip and adecent algorithm. And be able todo so even for vacuum tubes thathave not been invented yet.

For more info on PostScript, useAdobe’s and books, and my

book/disk combo.

Or, to really jump in with both feet,our package offers oneeach of everything needed to learnPostScript by all major authors at asubstantial savings. See my nearby

ad for more info.Lots of ready-to-use PostScript

files also appear on .Our usual reminder that most of the

sources mentioned appear either inthe or the

sidebars. Be sure tocheck here first before you call ourno-charge helpline.


$19.95

70 (!)

SCSII ANSIX3.131-1986 $50

211

DSP

PSRT

Cinefex

Film & Video

Sword & StoneNational Hair Technologies

Untapped Technology in Review

Skeptical InquirerBorderlands Quarterly

TektronixOscilloscopes: Selecting and

Restoring a ClassicStan Griffith

OlympusVideoimagescope

quarter inch

American NationalStandards Institute

Sound Practices Red BluePostScript Secrets

Whole Works

Synergetics

GEnie

Names & Numbers SpecialEffects Resources

New Tech Lit

72.6

Hardware Hacker

Hardware Hacker

viii

Keywords – Index

A sense for the fitness of things. – 68.6a sparce data set – 62.1A2 Central – 60.1absolute temperature – 64.3abstracts – 69.2absurd mythology – 55.5ac power – 49.1ac ringing voltage – 61.4acceleration – 58.2accelerometers – 58.2, 63.1Access Control – 70.6Accidental Empires – 55.6acoustical energy – 63.2Acoustical Society Journal – 63.3acquiring a lock – 54.3Acrobat – 69.5, 72.2, 72.3Actel – 56.6Active Filter Cookbook – 51.5, 54.5, 59.3, 65.3, 68.5Active Filter Design disk – 54.5active load – 49.2active low – 53.4active repeater – 57.3actor’s personna – 71.3A/D – 65.5A/D converter – 72.1ADA signage – 66.4addictive social disease – 53.2Addison Wesley – 55.6adiabatic – 53.2adiabatic process – 64.2, 64.3Adobe – 60.3, 69.4, 72.2 Adobe Acrobat – 72.2Adobe Photoshop – 70.2Adobe PostScript – see PostScriptadsorption cycle cooler – 68.3Advance Process Supply – 66.3Advanced Imaging – 58.3Advanced Linear Devices – 56.6Advanced Research Development – 49.3aerobic – 68.4aerobic exercise – 68.4aerobic exercise record – 68.3aerobic exercise software – 68.4AFC – 52.2AGC loop – 54.1, 68.5, 71.3, 71.4Aham Tor – 51.5air resistance – 63.4Aircraft Designs – 50.4

aircraft hacker books – 50.4AIS Satellite – 51.5alarm – 71.1algebra – 62.3All Electronics – 53.5Alladin – 62.6Allegro – 59.6Allen Organ – 55.6Alloy C – 61.3Almanac of UFO Organizations – 57.2,71.5Alpec – 63.6alphabet – 69.2alphanumeric display – 69.6alternate action circuits – 56.1alternate action pushbuttons – 56.2alternate cable service – 60.3alternate character set – 69.2alternate science – 57.1Alternative Transportation News – 69.6alternator power stepper – 70.6aluminum – 61.3Always Jukin’ – 71.5Amazing Archives – 67.6Amateur Radio Astronomers – 65.3amateur television – 70.6Amateur Television Quarterly – 66.5American Changer – 71.5American Machinist – 60.6American Natl Standards Institute – 72.5American Science & Surplus – 53.5, 61.3Amiga computer – 60.1Amperex – 59.6amplitude shift keying – 65.5Amusement Business – 63.6analog correlator – 54.2analog data storage – 72.1Analog Devices – 49.2, 49.5, 52.6, 58.2,60/6analog levels – 53.4analog tape cassette – 72.1analog thermometer – 52.1anamorphic scaling – 66.5, 67.1Anarchy 101 – 69.1ancient history – 58.1ancient pot – 70.4animated sequence – 60.1animation – 60.2, 71.1

Anixter – 58.5, 67.4answer – 61.4antenna – 49.4, 52.5, 53.2Antenna Engineering Handbook – 57.4antenna gain – 57.3, 58.4Antenna Handbook – 58.6antenna height – 58.5, 67.3antenna matching – 58.6antennafier – 58.6Antique Electronic Supply – 50.4Antique Radio Laboratories – 68.6antique tractors – 71.5any pulse – 68.6ap note – 49.5, 56.6, 61.1Apple – 51.5, 55.4, 59.6Apple IIe – 50.2Apple IIgs – 51.4AppleTalk – 59.3, 69.2, 69.3 approximations – 70.3aquarium cooler – 68.1archaeologic site mapping – 70.4archaeomagnetism – 70.4, 70.6Archie McPhee – 53.5ARclad – 50.4Arcturcus – 57.2Aria – 60.6Arizona Highways – 56.5array – 57.3ARRL’s Antenna Book – 57.4artesian hot well – 64.3artifacts – 50.1, 70.3ASCII character code – 69.2ASCII code – 69.2ASCII-85 – 69.3ASCII format – 69.2ASD/AMD TradeNews – 59.7Ashtech – 53.5Asian Sources – 59.7Ask the Guru – 57.5, 61.5, 65.1aspect ratio – 70.2Assn of Energy Engineers – 53.1, 63.5assorted wonderments – 58.3AST Servo Systems – 58.2asterisk – 49.5Astex – 50.4astronomy – 68.4Atochem/Pennwalt – 63.3attenuator – 67.4ATV – 66.5ATV Today – 70.6Audio – 57.4

Hardware Hacker

ix

audio – 71.3audio mixer – 60.6, 63.1audio mixing – 60.1authors – 72.2auto FAX – 72.2auto shopper – 70.1auto shopper quality – 55.4, 56.5AutoCad – 51.5autocorrelation – 54.2, 59.1AUTOCORR.PS – 54.3automatic frequency control – 52.2automatic gain control – 71.4automatic gain loop – 68.5Automatic Merchandiser – 71.5automatic mode sensing – 55.5automotive – 59.4average – 56.4averaging algorithm – 68.6Avery Dennison – 52.6avian raptor research – 60.4avoided cost – 64.4avuncular sleezoid – 62.2, 62.3Aware – 49.1, 50.1, 69.4Ayatolla’s Bar Mitzvah – 58.1

BA-1404 – 50.1, 52.4BA-1404 stereo FM broadcaster – 61.1B&H Video – 60.4back radiation – 52.4bad labwork – 67.5Bairn, Boyd – 60.4balanced – 58.5bandpass filter – 54.2bandsaw – 60.4bandwidth – 57.2, 57.4, 59.2barbeque lighter – 63.2barium titanate – 63.2Barker Codes – 54.3BASIC interpreter – 66.1BASIC Stamp – 66.1Basin-and-Range – 57.3Batelle Pacific Northwest – 69.6batmobile – 63.6bats – 54.4battery – 59.5, 66.1, 68.5batteries – 63.1baud rate – 66.1, 71.2baulin – 58.5BBS systems – 69.1Bearden, T – 67.6Bed & Breakfast – 60.4beepers – 63.2FW Bell – 62.4, 70.6Bell System Technical Journal – 59.1Benchmarq – 51.5

benders – 63.2bending – 63.4Bennet LaserBrite – 49.5Best of Analog Dialogue, The – 49.5Betacam – 60.4Bettering Nature’s Solar Cells – 53.2Bezier – 62.3Bezier cubic splines – 67.3Bezier curves – 62.1Bezier length formula – 62.4bicycle computer – 65.5bidirectional parallel ports – 70.6big-bad-wolf – 69.6binary – 69.3binary byte – 69.3binary cycle – 64.4binary data – 69.3binary encoding – 69.3binary format – 69.2binary optics – 71.1bingo cards – 59.7bionomial coefficients – 54.3bionomial math – 54.3birds – 52.6bitmap – 55.5, 69.4bitmap memory planes – 55.4, 55.6bizarre reading – 67.6Black Book Official Auction Report – 60.6black box approach – 61.1Black Lightning – 51.5, 54.5black magic – 58.6Black Range Lodge – 57.2black write – 70.2Blatant Opportunist – 52.6, 57.5, 61.5, 69.6 blends – 70.3Blevins, David – 57.2, 71.5Blick, Dick – 66.3blindfolds – 59.4blowing flag – 67.1Blue book – 72.5blue laser – 60.3BOD – see Book-on-demandBogey flicks – 71.3Boise IEEE.P1284 spec – 70.6BOOKDEMD.PS – 55.1BOOKDEMD.TXT – 55.1Book-on-demand – 57.5, 61.5, 66.5, 70.2Book-on-demand publishing – 55.1, 70.1, 72.2Books in Print – 69.2booster – 52.5bootleg copies – 61.1

Borderland Research – 67.6Borderland Sciences – 61.5Borderlands Quarterly – 72.5Borovec, Ron – 66.5bottoming cycles – 53.2bounceback – 52.1Braille – 66.3, 66.4Branson – 63.2brass wire – 60.4bread machines – 52.6brightness levels – 56.3British Thermal Unit – 61.3Britton, Don – 67.6broadcast FM – 57.2broken taps – 63.6brute force method – 55.4BTU – 61.3, 64.4, 68.2Buckyball – 58.4, 71.5Buckeyball research – 57.1Buckytube – 58.4bulldozer track – 70.3Burden’s Surplus Center – 53.5burn – 70.1burning – 56.5Burr-Brown – 54.5burst gate – 51.2bus – 60.2buzz – 53.4byte – 69.2Byzantine lawyers – 69.1

C&H Sales – 53.5cable – 66.1cable-tv suppliers – 67.4CADalyst – 51.5CAD/CAM – 51.5, 60.4, 62.1, 69.6, 72.1, 72.3calibration – 56.4caller ID – 49.4, 49.5, 50.1, 50.2, 61.3, 61.5, 63.1CALLERID.CAP – 49.5camera-ready charts – 59.3camera-ready figures – 66.2camera-ready quality – 69.5cancel – 59.2cancer – 62.4Canon – 59.6Canon color copier – 54.5Canon engines – 51.5Canon SX engine – 59.6capacitor – 56.2, 59.2, 63.3capillaries – 68.4Caplugs – 51.5Captain Video – 65.4capture effect – 58.4

Hardware Hacker

x

captured path – 66.2car alternator stepper – 69.5, 72.1car compass – 70.6car ignitions – 58.4car radio – 52.3carbide alloys – 60.5carbon-zinc cells – 52.2carnival ride – 71.1Carnivorous Plant Newsletter – 63.6Carnot, Sadi – 49.3, 64.1Carnot cycle – 64.2, 64.3, 64.4Carnot efficiency – 53.1Carousel – 60.3Carper, Dennis – 55.6cascading – 59.2Case Against Patents, The – 53.2, 68.6cash and carry – 69.2cassette recorder – 68.6casting products – 67.6catfish farm – 64.4CCITT format – 69.4CD – 50.1, 52.3CD audio – 70.3CD audio adaptor – 52.3CD-FM – 52.3CD-FM-1 – 50.1, 52.2, 52.3, 52.5CD-FM-1 hacking – 52.5CD ROM – 60.3, 69.4, 71.1CD ROM distribution – 55.1cell – 55.3cell biology – 64.1cell energy recycling – 52.2cellular phones – 58.6cellular radio devices – 56.6cent – 50.3Cerac – 65.5Cermetek – 49.4, 49.5, 61.4chamfer – 66.4channel – 69.4ChannelMaster – 58.5chaos science – 61.5character generator – 60.2character substitution – 69.3charge – 63.1charge pumps – 59.5chassis – 59.4Chekhov – 69.1chemical reactions – 64.1chemistry – 64.1Cherry Semiconductor – 59.7chest strap – 68.5chest unit – 68.5chilled mirror dewpoint – 68.4chimes – 59.3chirp – 54.4

chirp radar – 54.4, 59.1Chirp Radar – 59.1chord egg – 50.3chroma burst – 51.2chroma FX processor – 60.2Chromel – 63.1Chromel C – 61.3chrominance – 51.4Ciarcia, Steve – 55.6Cinefex – 72.5Circuit Cellar Ink – 52.2Circuit Specialists – 53.5Circuits Assembly – 66.3CircuitWerkes – 61.3, 61.4citations – 69.2clay tablet – 69.5claymation – 72.5climb – 67.1clipping – 72.4close encounter – 57.1Closed Caption TV Decoder – 57.5closed captioning – 51.2closed form solution – 62.3closepath – 67.2CMOS – 50.2, 52.1, 53.4, 56.2CMOS Cookbook – 56.3, 56.6, 59.5, 60.6, 65.5, 70.6CMOS Sequencer Solutions – 56.6coax – 58.5, 67.4, 67.5coax amplifier – 67.3coefficient of expansion – 61.3cogeneration – 64.4coherent radar – 54.4coil Q – 68.5coin changers – 71.5cold fusion – 52.1, 56.1cold method – 54.5color – 60.2, 63.2Color Key – 66.3color phase – 60.2Colorado School of Mines – 66.5Comb – 52.6comm channel – 69.3Commodore – 51.4, 52.2, 60.3communication trade journals – 64.4Communications data book – 56.6communications resources – 64.5community colleges – 55.1compare gate – 54.2comparing – 54.3compass – 70.5Compendex – 69.1, 69.2complementary patterns – 54.3Compliance Engineering – 62.4composite sync – 51.2

composite video – 51.3compress – 64.2compression – 69.4, 71.3compression ratio – 69.4compressor – 64.1, 68.4CompuServe – 69.2, 70.6computer art – 60.1Computer Graphics – 62.4computer language – 66.2Computer Shopper – 59.7Computers in Science & Art – 50.4computing language – 69.5condenser microphone – 63.2conductor – 60.5, 61.2, 65.2Consolidated Electronics – 54.5conspiracy – 56.1constants – 67.2constrain – 62.4construction financing – 64.4consultant referral – 62.6consumer apps – 62.1Consumertronics – 67.6contest – 71.3Continuous Tone Controlled Subaudible Squelch – 71.1contrast – 70.1control character – 69.2controversial technical areas – 67.6conventional current – 58.1conventional electric current – 58.1convergence – 71.3coolant – 64.4Cooley Brite Eradicable Sign Material – 66.4copper – 61.2copy protection – 61.1Coriolis force – 58.3corned beef sandwich – 68.4corner cutting – 67.2correlation – 54.1, 59.1correlation coefficient – 54.2cosines – 67.2cost – 66.1coupling – 63.3coupling transformer – 50.2Courier – 72.4cows – 49.1CPM computer – 52.6crater – 60.4Crawford, Chris – 57.5Creative Health Products – 68.6crest factor – 49.2Cringley, Robert X – 55.6crockery – 58.4cropping – 70.2

Hardware Hacker

xi

crosscorrelation – 54.2crosshairs – 51.2cross-linked – 66.3cross-mod – 57.5, 67.3, 67.4CRT – 70.6crystal – 50.2, 50.3, 63.1, 64.5crystal filter – 67.4crystal oscillator – 64.5crystal oscillator chip – 64.5crystal puller – 52.4crystal pulling – 52.2crystal set – 49.4Crystalprint – 70.4Crystals & Crystal Growing – 63.2Crystek – 63.2CTCSS – 71.1cube – 62.3cubic light years – 65.4cubic spline – 62.1, 62.2, 62.3, 67.3cuneiform – 69.5Curie Point – 63.3, 63.5current – 49.1, 58.1, 65.2current meter shunts – 61.2current sensing – 59.5current source – 65.2curve tracing – 62.4curvefit – 62.2curveto – 62.3, 67.2curvetrace – 62.3Cushcraft – 58.5cusp – 62.2cylinder – 64.2

D/A – 65.5D/A sound processing – 72.1Dak – 52.6Dallas Semiconductor – 49.5, 59.7, 61.4Damark – 52.6, 67.1darken – 56.3darkroom work – 54.5DAST – 72.1data – 71.1Data Book Volume 10 – 52.6data books – 56.6, 61.1data channel – 72.2Data Communications Products – 68.6data compression – 69.2, 69.3, 69.4data format – 72.2data path – 61.4data rates – 71.2data transmission – 69.2Databook – 51.5dc current – 68.1dc power supply – 63.5DCT compression – 50.1, 69.4

deblurring function – 56.4debunking – 67.6declination – 70.4decoder – 71.2dedicated computer – 66.1deflection circuitry – 59.2Delacorte – 65.3delta-T – 68.1, 68.2, 68.3demultiplexed stereo – 53.4dentist – 61.1dentist’s air turbines – 66.2derivative – 65.3Design News – 56.1Design Solutions – 63.6Design Tech International – 55.6desktop publishing – 69.5Desktop Video Data Handbook – 65.5despreading circuits – 51.1detector – 71.4device independent – 62.1, 66.2, 72.2Devtronix – 50.3, 50.4Dialog – 49.3, 53.1, 56.1, 59.1, 62.4, 63.3, 64.5, 69.1, 70.6dialplates – 72.1diazo – 66.3Dictionary of Technical Terms – 64.5die sinking EDM – 60.4dielectric – 63.1dielectric cutting fluid – 63.6dielectric fluid – 60.4, 63.5dielectric materials – 63.2diesel cycle – 64.2differencing – 69.4differential calculus – 65.3differential cooling – 58.3Differential GPS Explained – 70.6differential transfer – 54.5diffused blends – 70.3Digital Audio Transceiver – 57.5Digital Bogey – 71.3digital clocks – 63.2digital compass – 70.4digital correlation – 51.1digital correlator – 54.2digital filter – 65.5digital halftones – 70.1digital high pass filter – 71.2digital image – 56.2digital image processing – 56.3, 56.5digital photo imaging – 70.1Digital Processing – 60.3digital signal processors – 54.2digital thermometer – 68.3digital video effects – 60.2digital video layering – 60.6

digital voice technology – 67.6dimmer – 58.4, 67.6DIN-8 – 52.3, 53.5Dinsmore – 58.2, 70.5diode – 49.4, 59.4diode bridge – 54.2dipole – 57.1, 57.3, 58.5dipole folding – 58.4direct analog storage technology – 72.1direct cosine transform – 69.4Direct Imaging – 49.5direct toner printed circuits – 56.1direct toner method – 54.4directors – 57.3, 58.5Disability Bookshop – 71.5disk – 62.5disruptive effects – 61.1distant FM reception – 58.4Distillery – 69.5distillery – 72.3DISTILL.PS – 72.4distortion – 67.3Distressed Yuppy Surplus – 52.6dithering – 70.3division ratios – 50.3DKD Instruments – 51.1Dr Dobbs Journal – 54.5dodge – 70.1dodging – 56.5dodging masks – 56.5dodging paddle – 56.5dollar bill changer – 71.5dome keyswitch samples – 52.6dongles – 61.1Doppler burglar alarm – 63.2dot gain – 70.2, 70.3dots per inch – 55.1Doubleday Science Series – 53.2, 64.5downlinks – 57.5drain to source current – 59.4Drake Equation – 65.3Drake, Frank – 65.3drawing on a sphere – 67.1drills – 60.5driveway detector – 54.1drop shadows – 60.2dropout – 70.3dry film photoresists – 66.3DSP – 55.6, 65.5DSP algorithm – 72.5duplex data comm – 65.5duplex printing – 55.1duty cycle – 62.5dye methods – 53.2dye molecule – 53.1

Hardware Hacker

xii

dye-based solar – 53.1dye-based solar cell – 53.2DynaArt Designs – 54.5, 56.1, 72.2Dynachem – 66.3Dynamark – 66.3dynamic range – 56.5dynamic regulator – 52.4, 63.5DYS resources – 52.6

EAA Aviation Center – 66.5earthquake monitoring – 56.6Earth’s Field Magnetometry – 70.4Eastman Kodak – 66.3ECG – 50.2economic analysis – 64.4economics – 63.5, 64.1edge detection – 56.4Edge Heart Rate Monitor – 68.5editing – 60.1EDM – 60.4, 63.5, 66.5EDM capacitors – 60.6EDM machining – 63.5EDM resources – 60.5EDM Today – 60.6, 63.6Edmund Scientific – 53.5EDN Asia – 62.1EDO Acoustics – 63.2EE Times – 58.4EEM Master – 50.2EEPROM – 66.1EER – 68.1effective range – 57.2, 68.5efficiency – 49.4, 64.2efficient heat engine – 64.2E-field machine – 65.2EIA-220-B – 71.1EKG – 68.4, 68.5, 68.6EKG sensor – 68.4EKG-style – 68.5Elector – 55.1electret – 63.2, 63.3electret microphone – 72.2electric blankets – 61.2electric discharge machining – 60.3, 60.4, 63.5electric field – 65.2Electric Power Research Institute – 49.3, 62.4, 63.5, 64.5electric shielding – 50.4Electrical Engineering Circuits – 59.3electrical power – 63.5electrical recovery – 53.2electrochemical decomposition – 61.3Electrochemical Machining – 60.6Electrochemical Society – 71.5

Electroloy – 61.3electrolyte – 53.1electron current – 58.1electronic correlation – 54.1, 54.2, 54.4electronic halftones – 55.1, 55.3electronic halftoning – 56.6electronic music – 55.6Electronic Musician – 50.4electronic organ architecture – 50.4Electronic Product Review – 51.5Electronic Products – 50.2electronic surplus resources – 53.5electronic switches – 60.6electronic symbols – 58.1electronic tuning – 59.1Electronics Now – 55.1, 72.4Electronics World – 70.6electroplaters – 52.2electroplating – 71.5Electrorheological Fluids – 62.5elegant – 64.3elegant simplicity – 71.3Eletech Electronics – 72.1ELI THE ICE MAN – 49.2Elsworth Adhesives – 63.6Eltech – 67.6email – 62.6Embedded Control Handbook – 66.1embroidery machines – 62.2EMC Technology – 50.4encoder – 71.2Encyclopedia of Associations – 53.1, 55.6, 69.2energy – 59.3energy buildup – 59.1Energy Efficiency Rating – 68.1energy per cycle – 59.2energy recovery scheme – 64.1energy sink – 58.1energy source – 58.1energy transfer – 63.3engine interface peripheral – 64.5engineering – 64.1engineering design – 72.2entropic heat death – 49.1enthusiasm – 62.2Environmental Protection – 54.5eor – 54.2epoxy – 61.1epoxy strippers – 61.1EPRI – 49.3, 64.5EPROM – 54.2, 72.1equally tempered frequencies – 50.3equally tempered notes – 50.2equation space – 62.2

error – 70.2error diffusion – 70.1, 70.2ESR series resistance – 60.6ET watching – 65.3Etch-n-Peel – 66.4Ethernet – 59.3, 69.2, 69.3evaporative cooler – 68.3exact match – 54.1Exair – 68.4exclusive NOR – 54.2exclusive-OR gate – 59.5exercise – 68.4EXERCISE.GPS – 68.6exercise session – 68.6exotic fluids – 53.2Experimental Aircraft – 66.5Experimental Musical Instruments – 57.5Experimental Rotorcraft – 66.5explode – 63.5extension – 69.2extra-ordinary evidence – 61.5extraterrestrial intelligence – 65.3

Fabric – 49.3fades – 60.2Fahnstock clips – 50.4Fair Radio Sales – 49.2, 53.5, 58.2, 61.3, 63.2fake PostScript – 72.2Far East sources – 59.7Farmer’s Line Sets – 69.6Fast Proto – 70.6faster than light? – 56.1FASTFERN.PS – 69.5faults – 59.4Favor – 68.5FAX – 69.2, 72.2FAX compression – 69.4FCC – 49.3, 49.5, 61.3FCC part 68 – 49.3, 49.5feedback loop – 63.6Fermat’s last theorem – 69.1FERMAT.TXT – 69.1ferrite rf beads – 61.2ferrite rod – 68.6FET transistor – 67.4few chips shy of a full board – 56.1fiber optic comm – 64.5field – 60.2field safety – 70.4field strengths – 62.5filter – 69.5final point – 62.2findings for jewelers – 67.6

Hardware Hacker

xiii

FinePrint – 55.2fire department – 60.4fire hazard – 63.5Fistell Microelectronics – 55.6Flash, The – 51.5, 54.5flashlight cell – 52.2flattenpath – 66.2flexographic printing – 66.3flood zone risks – 64.4fluid – 64.4fluidic rate gyro – 58.3fluxgate – 58.1, 70.5fluxgate compass – 70.1fluxgate construction projects – 58.2fluxgate sensor – 70.5flywheel – 64.3FM – 50.1, 70.4FM antenna – 52.4, 57.1, 58.4, 58.5FM booster – 57.2, 57.4FM booster antenna unit – 57.3FM booster base unit – 57.4FM broadcast signal – 50.1FM DX – 67.3FM DX reception – 67.1FM receivers – 57.5FM reception – 57.2FM Tee antenna – 57.3FM trap – 67.1, 67.3, 67.4FM wireless broadcasters – 52.2, 54.1FMYAGI.PS – 57.3Foam Specifier Kit – 50.4foams – 50.4foils – 50.4folded dipole – 58.4Foleys – 71.3font – 72.4font eliminator – 72.4font software – 60.2FONTELIM.PS – 72.4four ET rating – 57.2four quadrant multiplier – 54.2Fourier – 56.4Fourier transform – 50.1, 54.44WD-on-demand – 62.5F-P Electronics – 69.6FPGA – 50.3fractal – 71.3fractal compression – 69.5fractal decompression software – 54.5fractal modeling – 61.5FRACTFRN.PS – 69.5frame bitmap – 62.3frame device – 55.1frame grabber – 60.2frame synchronizer – 60.3

framestore – 60.2free energy – 49.1, 59.2free energy resources – 67.1, 67.4, 67.5free kits – 62.5free samples – 64.5freewheeling diode – 62.5French curves – 59.3frequency – 62.5, 70.3frequency lock loop – 50.1, 52.2frequency selective – 59.2frivolous litigation countersuit – 53.1Fromm’s Big Blue Book, Randy – 63.6Fujitsu – 56.6full reversibility – 64.3furnace igniter – 63.4fusion rebuilding – 59.6fuzzy data – 62.3FUZZYBEZ.PS – 62.4

Gain – 58.5, 71.4gaffers – 71.3galactic noise – 58.4game coin mechanism – 71.5gamma – 70.2, 70.4, 70.5gamma correction – 53.3, 56.2, 56.3, 56.4, 70.2gamma curve – 56.3, 56.4, 70.2gamma match – 58.6garbage in, garbage out – 70.2Garden Fresh Replicas – 59.7Garner, Doug – 58.3gas – 64.2gas engine – 64.3Gas Engine – 71.5Gauss – 70.4Gearloose, Gyro – 66.5GE/Harris – 56.6General Electric – 59.6General Instruments – 59.6general purpose – 59.3general purpose computer language – 72.2generation loss – 60.1generator – 65., 65.1GEnie – 50.4, 60.1, 61.5, 62.1, 62.3, 63.6, 64.5, 66.2, 66.5, 67.6, 69.1, 69.2, 70.6GEnie PSRT – 55.1, 55.5, 59.4, 60.6, 62.6, 65.1, 66.5, 67.6, 70.1, 70.4, 72.5GEnie RADIO – 49.5genlock – 60.1, 60.2, 60.6, 63.1genlocking video encoders – 65.5geological formation – 70.4Geo-Monitor – 56.6Gerber – 65.5, 72.2

germanium – 61.2GhostScript – 59.4, 60.3, 62.3, 72.2Gila River – 64.4glitch – 49.1, 60.2, 62.2, 70.2Global Engineering Documents – 71.5Global Positioning Satellite – 51.1, 67.1global positioning system – 58.1glyphpath transform – 67.2Godzilla vs the Night Nurses – 69.4, 72.4goodwill ambassadors – 65.4gongs – 59.3GONZO15.PTL – 59.4GONZO15A.PTL – 62.4Gottleib, Mark – 55.6Gould – 59.6GoVideo – 60.3GPS – 55.6, 67.1GPS: A Guide to the Next Utility – 70.6GPS books – 70.1GPS Data Receiver, A – 51.1GPS front end – 58.2GPS navigation – 51.1, 53.5, 54.4GPS receiver boards – 67.1GPS receivers – 51.1GPS Resource File – 51.1GPS satellites – 58.1GPS World – 58.2, 67.1GPS World Showcase – 58.2graceful curves – 62.1grade Z horror flick – 57.2grain – 70.1grainy dots – 70.3Grantham Polly-Stamp – 66.3graph – 62.1graph space – 62.2graphic command – 69.2Grass Valley Group – 60.3, 64.5Gratzel, Michael – 53.2gray levels – 55.1, 70.2gray scale image – 56.3gray steps – 70.3Grecian urns – 56.6, 57.1Griffiths, Stan – 72.5grips – 71.3ground clip – 49.1Guitar Digest – 57.5guru – 59.4Gyration – 62.1GyroChip – 58.2, 58.3GyroPoint – 62.1gyro – 58.1, 62.1, 63.2Gyrostar – 56.1, 58.2, 58.3

Hardware Hacker

xiv

Hacker data format – 72.1, 72.4hacker integrated circuit – 63.1hacker microcontroller – 66.1hacker misconceptions – 63.3HACKFG51.PS – 51.2HACK56.PS – 69.5HACK59.GPS – 59.4HACK69.PS – 69.5hairpin loop – 58.5half power points – 59.2halftone – 70.1, 70.3halftone cell – 55.1, 55.3halftone process – 55.2halftone spots per inch – 55.2Hall compass – 70.5Hall effect – 58.2, 70.5Handbook of Chemistry & Physics – 65.3handicapped monitoring – 52.3Hapgood, Fred – 68.6hard disk – 66.2, 69.5hard paper – 56.5Hardware Hacker – 50.4, 52.6, 57.5, 58.6, 61.5, 66.4, 67.1, 69.5, 70.6Hardware Hacker reprints – 62.5Hardware Hacker III – 58.2, 59.3Harris Semiconductor – 59.6, 64.4, 64.5HDS Systems – 60.4HDTV – 69.4headphones – 51.2Hearst Business Communications – 50.2heart – 68.5Heartland America – 58.6heat – 68.1heat engine – 64.1, 64.2, 64.3, 64.4heat engine basics – 67.5Heat Engines – 53.2, 64.5heat flux – 68.2heat flux calculations – 68.1heat pump – 64.1, 64.3heat pumping curve – 68.1Heath Nostalgia – 68.6Heathkit – 55.1, 68.6heating – 49.2, 68.2heatsink – 62.5, 68.1Heatsink Application Handbook – 51.5heatsink thermal impedance – 68.2heavy metal – 52.5heddles – 69.6height – 58.6helical resonator – 67.4Hello Direct – 49.5Herbach & Rademan – 49.2, 53.5

herpes – 49.1Hewlett-Packard – 51.5, 55.2, 58.2, 59.6, 59.7, 69.6, 71.3hex format – 69.3H-field machine – 65.2Hi-8 – 60.1hidden factors – 67.5hidden PostScript grays – 55.4high ASCII – 69.2High Energy Enterprises – 56.1, 61.5, 67.6High Energy Research – 49.1high gain – 57.2high impedance – 59.3, 63.5high res typesetters – 70.1high side driver – 59.4, 59.5high vacuum – 68.4high voltage lines – 62.5highpass filter – 71.4hired gun – 55.5histo plot – 70.2histogram – 56.4, 56.5histogram equalized – 55.2histogram equalization – 56.2, 56.3, 56.5, 70.2Hitachi – 56.6, 64.5hoax – 57.1hole carriers – 58.1Holistic Technology – 57.5home automation – 71.1Home Office & Small Business – 55.6Home Power Magazine – 69.6Home Shop Machinist – 63.5homebrew PostScript – 66.2Hong Kong ripoff – 58.3Hong Kong Trade Council – 62.1horizontal offset – 67.1horizontal scale – 67.1horizontal scan rates – 53.3horizontal sweep circuitry – 59.3HOSB – 55.6Hoskins – 63.1hot method – 54.5hot spot – 58.6hot wire cutters – 61.2Hotronic – 60.3house paint – 53.2house trailers – 61.3HP laser service manuals – 51.5HPGL – 72.2Hughes – 49.5hum – 53.4human readable – 69.4, 72.2humidity sensor – 58.6Humphrey Products – 58.2

Hurst – 66.3HVAC Contractor – 68.4Hygenic Manufacturing – 67.6Hypercard – 72.2

IBM – 60.1IC Master – 50.2IC Sensors – 58.2ice – 68.3icemakers – 64.1id header – 50.2Iden – 60.3IEEE – 50.1, 58.1IEEE Press – 58.2IEEE Sonics & Ultrasonics – 63.3Ikegama – 60.3illegible artwork – 56.2illustration program – 72.3image – 69.2image operators – 55.3image processing – 56.2image quality – 69.5image striking – 58.3IMAGEKIT.PS – 56.3, 56.5, 69.5imaging tiles – 55.3impedance – 65.3impedance mismatches – 65.2incandescent bulb – 71.4incandescent lamps – 59.5inclination – 70.4Incredible Secret Money Machine – 50.4, 51.2, 52.5, 53.5, 55.6, 57.2, 58.6, 59.7, 61.3, 61.5, 62.3, 62.4, 63.5, 63.6, 65.2, 67.6, 70.6Incredible Secret Money Machine II – 65.5, 66.5, 68.6, 71.3, 71.5, 72.4india ink wash gray – 55.4inductive coupling – 68.5, 68.6inductor – 59.2Industrial Arts Supply – 67.6Industrial Laser Review – 64.5Industrial Marketplace – 59.7industry insider – 56.1inference and innuendo – 56.2inflection point – 62.2, 65.2, 65.3influence point – 62.2, 62.3information content – 70.4Information Display – 70.6Information Storage Devices – 72.1Information Unlimited – 67.6infrared – 65.5, 68.4Infrared Control ICs – 65.5infrared data communications – 65.5infrared detector – 68.4infrared diodes – 63.2

Hardware Hacker

xv

infrared people detectors – 63.3infrared viewer – 68.6initial point – 62.2injection molding machines – 67.6inrush filter – 59.5INSPEC – 69.1instruction set – 66.3insulated – 63.6insulator – 61.2, 65.2integrate – 54.2, 58.2integrated circuit manufacturers – 56.6Integrated Circuit Systems – 63.1Intel – 52.6interface – 49.3, 61.3Interface – 71.5interfering signal – 67.4interlace – 51.2interlaced scans – 53.3Int’l Assn for New Science – 68.1International Rectifier – 59.5Int’l Symposium on New Energy – 68.1International Transducer – 63.2Internet – 71.3Intersil – 59.6Intro to Magnetic Resonance – 70.5INVENORG.PS – 59.7invention marketing firms – 55.5Inventor Assistance Source Directory –69.6Inventor-Entrepreneur Network – 55.6inverter – 56.2Iron-Man Album – 71.5irreversible process – 64.2IRS – 55.1Is Anybody Out There? – 65.3ISAM – 58.3ISD – 72.1ISD1000A – 72.1, 72.2isoentropic heat death – 67.5isolate – 65.5isolation transformer – 63.6isometric – 67.2 isometric mapping – 67.1isopod – 68.6Isopod – 65.5isothermal process – 64.3Iterated Systems – 54.5, 69.5ITW/Fastex – 50.4

Jenison, Tim – 60.1Jerryco – 53.5Jet USA – 66.4jitter – 60.3Joint Photographic Experts Group –

69.4Jones & Bartlett – 49.1, 50.1Jones, Marlin – 53.5Joules – 49.3Jnl Acoustical Society America – 63.3Jnl Audio Engineering Society – 50.4Jnl Borderland Research – 67.6Jnl Computer Game Design – 57.5Jnl Institute of Navigation – 51.1, 58.2Journal of Navigation – 70.6JPEG – 69.4JS&A – 52.6junk science – 70.1

Kara Computer Graphics – 60.4KDKB – 58.5, 67.4Kelvin – 64.3Kepro – 53.5, 54.5, 66.3keyboard stretching – 50.3Keyboard Systems – 55.6keyer – 60.2kilowatt-hour – 49.4, 64.4Kimoto – 66.4kinetic energy – 59.3kit – 49.5, 50.2, 51.2, 57.2KJZZ – 67.4Kleerdex – 52.6KMC – 56.6knurled knob – 71.5Kodak – 60.3KPR – 66.3Kroy Color – 54.5Kukla, Fran & Ollie – 65.4KVH – 58.2Kydex – 52.6Kynar – 63.3, 63.5

L + R – 51.3L - R – 51.3LA basin – 71.3lab data – 49.1lab work – 56.1Lancaster Classics Library – 50.4, 54.5,56.6, 70.6Laplacian – 56.4Large Induction Coils – 57.5Larmor precession – 70.5Laser Diode Guidebook – 49.5Laser Focus Wrold – 63.3laser gyroscopes – 58.2laser pointer – 63.6laser printer – 54.5, 55.1, 62.2laser printer repairs – 51.4, 51.5laser repair – 59.6laser resolution – 56.5

Lasers & Optronics – 63.3LaserWriter Corner – 65.1LaserWriter G – 55.1, 55.6, 56.4LaserWriter Secrets – 52.6, 57.5, 61.5LaserWriter IIg Developer Notes – 56.4LASGCAL.PS – 56.4LASGNOTE.TXT – 56.4late night talk shows – 52.2latent heat recovery – 53.2lateral charge migration – 52.1latitude – 67.2lava tube cave hunting – 70.4laws of thermodynamics – 56.1, 64.1layer – 69.5Lazer Products – 51.5, 54.5LC product – 59.2LC ratio – 59.2LCD – 70.6lead zirconate titanate – 63.2leading zeros – 72.4lean – 67.1learning curve – 60.2LED – 70.6lefthand motor rule – 58.1Lempel-Ziv-Welch – 69.4Lena – 70.1Lena digital image – 56.4Lena image – 69.6LENA.PS – 55.5, 56.3, 56.6, 69.5LENAHIST.PS – 55.5, 56.6, 69.5length – 62.3lepcon – 49.3letterhead – 56.6Lexmark – 55.4light bulb – 71.4lighten – 56.3Lighting Dimensions – 53.5Lightning Bolt Generators – 57.5lightning protection – 57.4Lightwave 3D – 60.2limited grays – 70.2Lindsay Publications – 49.1, 57.5, 60.6, 67.6line – 62.5, 67.2line level audio – 52.5linear – 50.1linear amp – 68.5Linear Circuits Handbook – 63.6Linear Circuits Data Book – 70.6linear data books – 55.6linear graphics transform – 67.1linear reactance modulator – 52.4linear regulator – 62.5linear stepper – 66.3

Hardware Hacker

xvi

Linear Technology – 59.5, 68.5, 71.3linearly swept FM – 54.4lineto – 67.2lingo – 56.1lithium coin cell – 68.6lithium salt – 53.2litho paper – 56.5live steam – 53.1, 63.3LM1881 – 51.2local area network – 64.5local maximum – 65.3local minimum – 65.3lock-in amplifier – 54.1log – 50.1long distance FM – 57.2long distance FM antenna – 58.5long line canceller – 67.4long line trap – 67.3longitude – 67.2loop – 62.2Lor’d – 61.5, 67.6lossless – 69.4low ASCII – 69.2low level fields – 70.4low sensitivity – 70.5lower case – 69.2lowpass filter – 56.4, 71.4Loyola Enterprises – 51.1LT1037 – 71.4lubricants – 58.4lumeloid – 49.3, 49.4luminance – 51.4, 56.3Lutech – 71.5LZW compression – 69.4

M&R Marking Systems – 66.3Mac – 60.1, 60.3Mac Video Gateway – 60.3machine language – 66.1macros – 66.1mag stripe readers – 70.6Magazine of Service Management – 55.6magic – 69.6magic cookies – 57.1magic resources – 69.4magnetic compass sensor – 58.2magnetic field – 62.5, 65.2magnetic resources – 70.6magnetic sensor – 58.2Magnetics – 70.6magnetoresistor – 70.5magnetostriction – 61.2Mahantango Manor – 69.6MANDRILL.PS – 69.5

man-made noise – 58.4marketing scam – 53.2Markowitz, Jerome – 55.6Marks, Alvin – 49.3Marlin Jones – 53.5mask signal – 54.2master flip flop – 56.2matching – 63.3MathSci – 69.1, 69.2matrix – 51.3matrixed stereo – 51.3Maxim – 59.5, 62.5, 68.5maximum – 65.2maximum power transfer – 65.1maximum power transform theorem – 65.1max-min theory – 65.2, 65.3MCM Electronics – 54.5, 63.6McMaster-Carr – 66.5MeadowLake – 54.5meals in minutes – 52.6Measurement & Control – 58.2mechanical force – 63.1mechanical gryo – 58.2, 62.1mechanical motion – 63.2, 70.5mechanical resonances – 61.2mechanical stuff – 56.6mechanical work – 64.1Media Magic – 50.4medical therapy – 68.4medieval armor – 72.5meditation – 50.3megabytes – 72.1Melcor – 68.1memory use efficiency – 55.4Meowwrrr – 62.4MER Inc – 58.4Merigraph – 66.3metal barrier diode – 53.2metal disintegrator – 60.4, 60.5Metal Disintegrator – 60.6Metalfax – 60.6Metermaster – 70.6Michelin Guide – 57.2Michigan Inventor’s Council – 53.2Micro Cookbook I – 52.2, 66.2Micro Mint – 55.1, 55.6Micro Switch – 58.2Micro-Avionics Newsletter – 53.5MicroChip Data Book – 66.1Microchip Technology – 66.1microcontroller – 52.2microinch machining – 60.4microlithography – 49.4microOhm-centimeters – 61.2

micropositioner – 63.2micropower crystal oscillator – 64.4, 64.5microprocessor – 52.2microscope stage – 68.4microsizing – 66.5, 72.2Microwave News – 62.4microwave plasmas – 50.4Microwaves & RF – 58.2Microwaves New Product Digest – 63.2MIDI – 50.3, 55.6, 63.1, 69.2Midnight Engineering – 53.2, 54.5, 55.6, 69.6mini-amplifier – 51.3Minicel – 64.5Mini-Circuits Labs – 57.2minimum – 65.2ministry of propaganda – 60.4Ming Engineering – 72.1mirror patterns – 54.3misinterpretation of data – 67.5mismatch – 65.2MIT – 68.6MIX Bookshelf – 50.4MK50240 – 50.2Modem Databook & Applications – 51.5modifying – 67.2module – 68.1, 68.2Moire patterns – 55.3Mondo-tronics – 68.6monitor resolution – 53.4monolayer – 53.2Morse Code – 54.1MOS power transistor – 59.1MOSFET – 59.4MOSPower Applications Handbook – 59.1most putrid gray – 55.4Mostek – 59.6Motion – 59.1motion artifacts – 68.4Motion Control – 59.1motion estimation – 69.4Motion Pictures Expert Group – 69.4motor controls – 62.5Motorless Motion – 68.6Motorola – 49.5, 50.1, 50.2, 57.5, 58.2, 59.5motors – 49.1mouse – 60.2moveto – 67.2movie – 71.3MPEG – 69.4

Hardware Hacker

xvii

MPEG compression – 60.3MSC – 66.5MSM – 55.6multi-level marketing – 65.4multimedia – 60.4multimedia editing – 58.3Multimedia Gulch – 65.5multimedia resources – 71.3multimedia slide show – 71.1multi-message – 72.2Multi-Out connector – 51.2, 51.3multipath – 57.3multiple master fonts – 72.4multiplexed audio – 52.4multiplexed stereo – 53.4multisyncing monitor – 53.3multi-tasking UNIX – 66.1mumbo jumbo – 56.1munchkin division – 53.4Murata – 56.1, 58.2, 58.3, 63.2museum – 72.1music – 72.1music frequencies – 50.2music synthesizer – 63.1musical toys – 50.3Musty Manuals – 55.1MWS-675 – 61.3MWS Wire Industries – 61.3MX-Comm – 58.6, 71.1MX275 – 71.2MX315A – 71.2MX365A – 71.2MX375 – 71.2mylar blades – 63.3

N channel – 59.4N channel power MOSFET – 59.4Names & Numbers – 51.1narrowband Yagi – 58.5NASA – 58.3Natl Assn for New Science – 67.6National Hair Technologies – 72.5National Semiconductor – 62.5Nature – 53.2navicube – 58.1, 62.1navicube resources – 58.6Navitech Book & Software Store – 64.5Navtech Information Service – 55.6NEC – 59.6, 63.3, 65.5negative – 58.1negative acting – 66.3negative energy – 63.4Neo-Geo – 53.4Neo-Geo connector – 53.3

Neo-Geo interface – 53.1, 53.4neon lamp relaxation oscillator – 60.5New Age Alternatives Discount Catalog – 61.5new age nineties – 58.1New Energy Technology – 49.3New Mexico – 57.2new microcontroller – 66.1New Science News – 67.6NE605 – 54.2Newman Motor – 52.2NewTek – 49.5, 60.1, 71.3Nichrome – 61.3Nichrome wire – 61.2Nikrothal 6 – 61.3Nintendo – 51.4Nintendo game cartridge – 63.6Nintendo interface – 52.1Nintendo-to-anything interface – 51.2ninth grade algebra – 67.1noise – 70.3noise effects – 66.1noise figure – 57.5noise levels – 58.4noisy FM signal – 57.4non-interlaced scans – 53.3non-ionizing radiation – 62.4nonlinear editing – 71.3nonlinear graphics – 67.1nonlinear graphics transform – 67.1Nonlinear Nonsense – 61.5nonlinear resistance – 71.4nonlinearities – 56.4non-transparent – 69.2nonvolatile array – 72.1Nonvolatile Serial Programmable Devices – 49.5non-Von – 66.1NOPATENT.PS – 59.7NOPATENT.TXT – 53.2normal – 67.2normalization – 65.3NovaSensor – 58.2NPN power transistors – 59.4NTE – 50.2NTSC – 51.2, 53.3, 53.4, 60.2, 63.2Nuclear Magnetic Relaxation – 70.5null – 67.4numeric analysis – 50.1Nuts & Volts – NUTS3.PS – 53.5, 54.5NUTS9.PS – 59.4NUTS10.PS – 60.6

Object – 72.3

obscure religious references – 56.2obscure rural newspapers – 56.2obscure tech books – 67.6obtuse – 69.1Ockham’s razor – 52.1, 57.1Ockham, William of – 52.1octal notation – 69.3octave – 50.3odd and even fields – 51.2off-hook – 61.4offset – 62.3Ohm’s law – 61.3ohmic – 59.4ohmic terminal – 59.4OKI Semiconductor – 53.5, 61.5, 72.1Old Colony – 55.1old-line flicks – 71.3Olympus – 72.5on resistance – 59.4on-demand publishing – 51.1on-hook – 61.4one way publication – 72.2opaque mask – 56.5optical antenna – 49.4Optical Engineering – 58.4optical film – 49.3optical link – 57.3optical mouse – 65.5optical wavelets – 58.4opto chips – 65.4, 65.5Optoelectronic Designers Catalog – 69.6Optoelectronic Products Catalog – 56.6optoisolator – 61.4O’Regan, Brian – 53.2Orgone Energy Blankets – 67.6Origin of Radar – 59.1oscilloscope – 49.1, 51.2, 53.4, 71.1Oscilloscopes: Selecting & Restoring –72.5Otto cycle – 64.2Oughtred Society – 68.6output power – 65.3outright cons – 67.5outright hogwash – 68.1Outwater Plastics – 56.6overlay bus – 60.2overload – 59.4, 67.4oversampling – 70.2

P channel MOSFET – 59.5P-38 can opener – 71.3page bitmap – 55.1page descriptions – 69.5Page, Robert – 59.1

Hardware Hacker

xviii

pagemaking program – 72.3pagers – 58.6PAIA Electronics – 50.3, 50.4, 55.1, 55.6PAL – 53.3paleomagnetism – 70.4, 70.6panning – 58.3paper grade – 70.1paperless office – 72.2papermaking – 60.4parabola – 65.3Parallax – 66.1parallel – 69.2parallel port – 66.1parallel resonance – 52.4parallel resonant circuit – 59.3parallelogram – 67.2parameter – 62.2paranormal – 67.6parasitic elements – 57.3part 68 interface – 49.3, 49.5, 50.2part 68 telephone interface – 61.3Parts Express – 67.6pass through type approval – 61.3passive repeater – 57.3patent system – 55.5patents – 49.3, 53.1patents – see Case Ageinst Patentspathforall – 66.2PC host – 66.1PC Techniques – 67.3PCBF-1000 – 54.5PCIM – 59.1, 59.6pel – 56.3, 70.2Peltier effect – 68.1penny stock – 49.3periodical chart – 65.5perpetual motion – 49.1, 56.1, 64.1, 67.6perpetual motion machine – 52.2personal computers – 56.2personality disorders – 57.1perspective storefronts – 67.1Peterbilt trucks – 55.1Phaedra – 57.2, 71.5phase – 49.1phase angle – 49.2phase cancellation – 67.4Philips – 59.6, 62.6phone signalling – 63.6photo film – 56.5photo halftones – 55.1PhotoCD – 60.3PhotoGrade – 55.4, 56.4Photonics Spectra – 58.4

photons – 53.2photopolymer resources – 66.4photopolymers – 66.3photos – 72.2Photoshop – 60.3photosynthesis – 49.4, 53.1, 53.3, 64.1Phototherm – 49.3phototypeset – 59.3physical laws – 61.5physics – 64.1piano & organ resources – 50.3, 50.4piano tuning – 50.3piano tuning aides – 50.3Piano Tuning & Allied Arts – 50.3PIC – 66.1PIC16C56 – 66.1picket fence – 57.3picture element – 56.3, 70.2picture-in-picture – 60.2picture-in-picture controller – 64.5picture quality – 53.3picture resolution – 53.3Pierce oscillator – 52.4piezo – 58.2piezo device – 63.3, 63.4, 63.5, 65.2Piezo Electric Products – 63.3piezo fans – 63.3piezo gyro – 58.3piezo gyroscope – 56.1Piezo Kinetics – 63.3piezo micropositioner – 63.2piezo oscillator – 58.3piezo power generation – 63.5piezo rate gyro – 58.2piezo resources – 63.4, 63.5piezo striker – 65.2, 65.3piezo trade journal – 63.5piezo transducer – 63.3Piezoceramic Manufacturer’s Assn – 63.3piezoelectric effect – 63.1, 63.2piezoelectric generator – 53.1piezoelectricity – 63.1piggy bank – 59.1, 59.3pilot – 52.4pilot light – 71.5pilot project – 68.3Pioneer – 52.2, 52.3pipe dreams – 64.1pitch blending – 50.3pitch references – 50.3Pixar – 60.3pixel – 56.3, 70.2pixel dot sizes – 55.6Planetary Assn for Clean Energy – 49.3

Plass, Michael – 62.4plate-through holes – 58.4Play Meter – 58.6, 71.5playback – 72.1Player Piano Company – 50.3. 71.5"Please buy my house" – 52.3Plessey – 67.1plethsymograph – 68.4PLD Shell Plus – 52.6Plot Data Format Reference Book – 65.5plotter pen – 66.2P-N junctions – 59.4point – 67.2Polar – 68.5polarize – 52.2polarization – 57.4poles – 59.2police radar – 62.5pollution – 49.3Pollution Equipment News – 54.5polyacetylene – 49.4polymeric release coating – 56.1Popular Electronics – 50.3Popular Science – 63.5pork fat sandwich – 68.4porphyrin – 49.4position – 58.2positive – 58.1positive feedback loop – 69.6Post-Newsweek Cable – 57.2post-production – 60.1PostScript – 52.5, 54.2, 54.3, 54.5, 55.1, 55.2, 55.3, 56.3, 59.3, 59.4, 60.3, 60.6, 65.1, 65.2, 66.2, 66.4, 68.4, 69.1, 69.5, 70.4, 72.2PostScript books – 62.6PostScript code – 59.3PostScript level II – 69.4PostScript photo halftones – 55.4PostScript Reference Manual II – 69.5PostScript Secrets – 62.4, 72.5POSTVECT.PS – 66.2potassium sodium tartrate – 63.2potential energy – 59.3potting – 61.1power – 49.1Power & Bulk Solids – 57.1power density – 65.2power distribution – 52.4Power Engineering – 64.5power factors – 53.1power generation – 63.5power generator – 65.3power inverters – 62.5

Hardware Hacker

xix

power lines – 62.4power MOSFET – 59.5power relay – 59.5power semiconductor – 59.6power supply ripple – 68.3Power+Arrays – 67.6PowerTechniques – 59.1Poynter, Dan – 72.2predriver – 52.5Premium Parts+ – 67.6preview bus – 60.2price list – 56.6, 61.5printed circuit – 53.5, 54.4, 56.1Printed Circuit Board Transfer Film – 56.1printed circuit supplies – 66.3Printer’s Devil – 61.5PRNCRCT.GPS – 53.3, 53.5, 54.5Product Databook – 56.6, 56.7Product Handbook – 58.6product marketing – 55.5product marketing resources – 55.5, 55.6program bus – 60.2Programmable Devices Wall Chart – 62.6Programmable Peripherals Design – 52.6progress detector ics – 63.6Projects Unlimited – 63.2proof copy – 59.3proprietary code – 72.2protection – 59.5proton precession magnetometer – 70.5Prototype Development Providers – 69.6pseudo radio astronomy – 52.1pseudoscience – 56.1, 56.2, 57.1, 70.1PSRT – 67.6, 69.5P-substrate – 59.4psychological needs – 57.1pulse – 63.4pulse monitor – 68.2, 68.4pulse monitor chips – 68.6pulse monitor resources – 68.4push to listen – 71.2puss de resistance – 62.3, 62.4p-v diagram – 53.2, 64.1, 64.4PWM – 66.1pyroelectric – 63.2, 63.3PYXIS Backpacker’s GPS receiver – 67.1PZT – 63.2

Q – 59.1, 59.2

Q values – 67.3QMS – 51.5, 55.4, 59.6quacks like a duck – 56.1, 57.1quadrant – 59.5quadratic spline – 62.2quality – 59.2, 69.4quality factor – 59.1Quality Technologies – 56.6quarter wave plate – 49.4quarter wavelength – 67.5quartz – 63.1QuickTime – 60.3quieting – 67.4Quik Voice – 72.1quinone – 49.4

R + L – 53.4R - L – 53.4R&D Electronics – 53.5rabbits – 69.6Rad Lab One – 59.1radar – 54.4Radar Handbook – 59.1radar range – 59.1Radar Systems Engineering – 59.1Radio Observer – 65.3Radio Research Instruments – 58.2radio restoration – 68.6Radio Shack – 53.5, 57.4, 57.5, 58.2, 71.1, 72.1radio star – 65.4Radio World – 60.6Ragtime – 64.5RAM – 72.1RAM based video – 60.3random – 70.4random byte – 69.2random number – 67.3RANDOM number generator – 66.1range – 52.5Rankin cycle – 64.2Rankine – 64.3, 67.5radio restoration – 68.6rate gyro – 58.2, 62.1, 63.3rathole – 64.2ratty – 67.3RCA – 59.6RCA Review – 57.4reactance – 59.2reactance modulator – 52.4reactance plot – 67.5reactive power – 49.2reactive voltage – 59.2real science method – 56.1reality check – 64.4

receiver front end – 67.1Recharger – 51.5, 54.5recorders – 60.3rectangle – 67.2rectifier – 53.2recycle – 52.2red book – 69.5, 72.5redefining gray levels – 56.4Redmond Cable – 51.1, 51.2, 53.5, 55.6Rees, John – 69.6, 70.6, 72.1reflection – 65.1, 65.2reflector – 57.3refrigerator – 64.1, 64.3regulator – 49.2REI – 68.5rejected heat – 64.4relay – 56.2relaxation oscillator – 60.5remote controls – 67.6remote robotics – 71.1Renderman – 60.3rent-a-vid chain – 60.4repeating artifacts – 70.3RePlay – 58.6, 71.5reprints – 72.1reprogray – 55.4resin molding – 72.4resistance – 61.2, 61.3resistance values – 61.2resistance wire – 61.2, 61.3, 63.1resistive – 63.4resistivity – 61.1, 61.2resistor – 59.4, 59.5resolution – 55.1, 70.1Resolution Enhancement – 55.2resonance – 59.1resonance frequency – 59.1, 63.1Resonance Research – 66.5, 67.6resonant coil – 68.5resonant power – 59.3resonant swithcing tricks – 59.2resonant voltage increase – 59.2Resource Bin – 57.5, 61.5, 65.1, 67.6Resource Central – 64.5resource sidebar – 51.1Resources Unlimited – 68.6Reticon – 59.7RETOUCH.PS – 70.4reverse slash – 69.3reversible – 64.2reversibility – 64.1Rex Research – 70.1Rexearch – see Rex ResearchRF Design – 65.5rf transmission lines – 65.1

Hardware Hacker

xx

RGB – 53.5RGB video – 53.3rho – 61.2rhombic antenna – 57.4rhombic FM antenna – 57.2Ridenour, Louis – 59.1Rife Resonators – 67.6righthand generator rule – 58.1ring detection – 49.5, 50.2ring detector – 61.4ringing decay time – 59.2ringing time – 59.3RMS power – 49.2Roadable Aircraft – 66.5Roberts Electric – 69.6robotic muscles – 62.5Rochelle Salt – 63.2Rockwell – 58.2rodeo events – 60.4Rodeo Video – 60.4Rohm – 52.4Roller Derby – 65.4ROM – 72.1rootbeer – 67.3rootbeer cup – 67.1rosette grips – 71.5Rotary Flight International – 66.5rotating – 67.1RoundTable – 69.1royalty – 72.3royalty-free interface – 66.4RS-232 – 50.2RS423 serial comm – 66.2rubber iguana – 53.5, 57.1rubber stamps – 66.3run length encoding – 69.4ruthenium dye – 53.2Rutland – 51.5

SAE Library – 64.5Sagan, Carl – 56.2, 67.6sample idea kit – 51.5Sams – 55.1sapphire – 61.3Santa Claus machines – 54.5, 66.3satellite book – 51.5Satellite Watch News – 61.5saturable toriod – 70.5saturation effect – 59.4SAW device – 52.4, 63.2SAW Scene – 67.6Sawtek – 67.6scaling – 67.1scam – 49.1, 64.4scavenging cycles – 53.2

schematic – 52.4, 68.6Schmidt trigger – 56.2school paper – 49.3, 62.5School Shop catalog – 51.5Schottky diodes – 54.4Science – 62.4, 62.5Science Citation Index – 70.6science fair – 49.3, 68.4science fair project – 62.5Science Under Siege – 66.5scientific method – 67.6scope – 68.5Scrambling News – 61.5Screamer – 71.3screen angle – 55.3screen size – 55.2scribble – 67.3SCSI – 59.3, 69.3SCSII disk comm – 72.5Seattle Robotics Society – 61.5SECAM – 53.3secret gray map – 55.4secret tricks – 56.4secret waveforms – 68.5SECRTEMP.GPS – 59.4selective calling – 71.1self-collating – 72.2self-publishing – 69.6semiconductor – 59.6, 61.2semiconductor chip houses – 56.6Semiconductor Master Selection Guide– 70.6Semiconductor Reference Guide – 50.2semiconductor resources – 61.5semiconductor resources I – 56.6semiconductor resources II – 59.6semiconductor resources III – 61.4Semiconductor Sensors Data Handbook – 62.6semi-log – 59.3semilog artwork – 59.3semitone – 50.3semi-wireless – 52.3Sensors – 58.2, 62.6SenSym – 58.2sequence – 67.1serial – 69.2serial computer control – 71.2serial data receiver – 66.1serial EEPROM – 66.1serial port – 69.2series resistance – 52.2series resonance – 59.3series resonant circuit – 59.1Serigraph – 51.5

Serpac – 49.5SETI resources – 65.3, 65.4set-reset flip flop – 56.2setscreen operator – 55.374HC13 – 56.2sewing machines – 68.4SGS/Thompson – 51.5, 59.6shake the box project – 51.1shared information – 69.1Sharp – 65.5, 69.6sharpen – 56.4Sharper Image – 52.6Shear-Loc – 71.5sheet rubber products – 67.6Sheldahl – 58.4Sherlock, Mike – 57.2shielded cables – 51.3, 53.4shielding – 57.3shifted autocorrelation – 54.2, 54.3shifted autocorrelation functions – 54.3, 54.4shifted bit patterns – 54.3short – 59.1, 59.4, 67.5short form catalog – 56.6short haul telemetry – 65.4, 65.5, 68.4, 68.5, 68.6SIAM – 58.3Sierra – 60.6Siggraph – 62.4sign routing machine – 69.6signal to noise ratio – 57.4, 58.5signcutter – 62.1Signetics Philips – 50.4, 54.2, 56.6, 65.5silicon – 59.4, 61.2Silicon Systems – 64.5, 71.1Siliconix – 59.5silver – 61.2silver halide – 56.3simple latches – 56.1simple switcher – 62.5Simonton, John – 55.6sines – 67.2sinewave – 49.1, 50.3sinewave generator – 71.3single frame edit – 60.3single frame writes – 60.1, 60.2single pole – 71.4singles bar pickup line – 60.3sink – 49.3size – 72.4SK – 50.2Skeptical Inquirer – 57.2, 67.6, 72.5skeptical inquirer – 57.1Skilling – 59.3Skolnick, Merrill – 59.1

Hardware Hacker

xxi

Skyvision – 51.5slave flip flop – 56.2sleep mode – 66.1slope – 62.3, 65.2, 65.3slope of the slope – 65.3slopping-in-the-slush – 56.3slot canyon photos – 56.5slow blow fuse – 59.5small hole EDM – 60.4Small Parts – 51.5, 66.5smart – 59.4smeared ink – 56.2Smith Chart – 49.1, 59.4, 67.5Smith Chart drawing routines – 59.4SMITHCHT.PS – 49.1, 59.4smog – 71.3smooth gradient – 70.2SMPTE Time Code – 63.1snap action – 59.5Snaptron – 52.6S/N ratio – 58.4Society Automotive Engineers – 64.5Society Industrial & Applied Mathematics – 58.3Society Optical Engineering – 53.5socket head caps – 71.5sodium triphosphate – 66.3soft focus – 56.4soft paper – 56.5solar breakthrough – 53.1, 53.2solar cells – 49.4, 65.1solar energy conversion – 53.2solar fiasco – 68.3Solar Mind – 57.5solar panel – 64.4solar power – 64.1solarize – 55.3solder – 63.3solder mask resists – 66.3Solid State Camera Products – 59.7sonar – 63.2Sony – 51.4, 52.3, 53.1Sony Betacam – 60.1Sound & Communications – 62.6Sound & Video Contractor – 62.6sound effects – 72.1sound installers – 62.6Sound Practices – 72.5source – 49.3source code – 72.2source impedance – 53.4Southern Sign – 66.3Space Systems Division/MZEE – 51.1spacial filtering – 67.4spacing – 58.6

spark gap transmitter – 60.6spark machining – 60.4sparking – 49.3sparse data – 62.2, 62.3sparse data set – 62.1, 67.2, 69.5Special Editions – 53.4special effect – 71.3, 72.4specialty booksellers – 67.6specialty hardwoods – 57.1speech application notes – 53.5speech chips – 72.1speech recognition – 54.1speech scrambling – 58.6, 71.2speed – 66.1, 72.4speed penalty – 72.4SPEEDUP.PS – 59.4, 69.5, 72.4Speleonics – 59.7, 67.6, 70.6sphere – 67.2spherical mapping – 60.2SPIE Technical Publications – 53.5, 58.2spline equations – 62.3splines – 59.3spot cooling – 63.3spot densities – 55.2spot patterns – 55.2spotless halftones – 70.1, 70.3SPOTLESS.PS – 70.4Sprague – 59.6spread spectrum – 54.1spread spectrum codes – 51.1spread spectrum communications – 54.3, 65.4Spread Spectrum Handbook – 61.5Spread Spectrum Scene – 55.6spurs – 57.5square – 67.2square law response – 56.4square pixel – 56.4squelch tails – 71.2SRS Encoder – 61.5standing waves – 65.1, 65.2Stanford Telecomm – 54.2, 61.5star wars lettering – 67.1STARTUP.PS – 66.2, 69.5Statek – 63.2station sync – 60.3status quo – 71.4steam calliope – 63.6step method – 62.2steps – 70.2stereo broadcaster – 52.4, 52.5stereo FM broadcaster – 61.1stereo sound – 51.2stereolithography – 54.5

Stewart, RA – 66.3Stirling – 64.5Stirling cycle – 64.2Stirling engine – 64.2Stirling Machine World – 69.6stock market analysis – 72.2stock quotes – 51.2Stone, Maureen – 62.4stopwatch – 68.5, 68.6store display fixtures – 56.6stored energy – 59.3storyboards – 60.1stretched banners – 67.3stretched keyboard – 50.4string – 54.3, 69.5stroke – 62.2strong clear adhesives – 52.6STR2FILE.PS – 69.5Stuart, WF – 70.4student paper topic – 62.6studs – 60.5subaural – 71.2subharmonic lumps – 52.4submicron distances – 49.4subscripting – 72.4substrate – 59.4substrate diode – 59.1Subsurface Exploration Technology – 66.5Sunday funnies – 70.1Sunday funnies effect – 55.3super efficient heatsink – 68.1Super Nintendo – 51.1, 51.2, 52.1, 53.4Super Nintendo connector – 51.3Super Nintendo interface – 51.4, 53.5Super Science – 67.6super VHS – 51.4, 52.1, 60.1superconductors – 61.2superinsulated – 68.2, 68.3supersearch – 69.2Supplies Unlimited – 54.5surface modeler – 62.1surface wave devices – 63.2surplus – 68.1surplus resources – 53.5Surplus Traders – 53.5switch – 49.3switcher – 60.2switching regulator – 62.5switchmode regulator – 62.5switchmode resources – 62.4, 62.5sync amplifier – 53.2sync demod – 54.2sync lines – 53.4sync separation – 51.1

Hardware Hacker

xxii

sync stripper – 51.1sync tips – 53.4synchronous demodulator – 54.1synchronous full wave rectifier – 54.2synchronous rectifier – 54.4, 59.1, 59.5Synergetics – 51.5, 53.5, 55.6, 56.6, 58.6, 60.6, 61.5, 63.5, 63.6, 65.5, 66.5, 68.6, 70.6, 71.5, 72.4, 72.5Synergetics Consultants Network – 55.6, 60.6synthesized receiver – 52.5synthesizers – 63.1system noise – 50.3Systron-Donner – 58.2, 58.3SX fusion assembly laser – 59.6SX Fuser Assembly Master Kit – 59.6

T-Rex – 72.4Tab – 55.1tabloid news – 55.2takeup reel – 60.4talk-off – 71.2talking card – 72.1tangent – 62.2, 65.3tapicoa pudding – 69.4taps – 60.5target phase histories – 54.4target zone – 68.4Taylor, Rolf – 64.5TDK – 62.6TE module – 68.6TE module guidelines – 68.3TEC-200 – 54.5tech education products – 67.6tech hotline – 59.7Tech Notes from a Telephone Engineer– 66.5technical ceramics – 63.2technical illustrations – 72.2technical innovation – 69.6technically weird – 70.1Techniks Incorporated – 53.5, 54.5, 72.2tee-handles – 71.5teenage sex – 55.1Tektronix – 72.5telco – 56.6telephone fundamentals – 66.5teletext – 52.6Teltone – 63.6, 71.1temper – 60.5temperature coefficient – 61.3temperature difference – 68.2temperature drop – 68.1temporal content – 58.3

Ten Lectures on Wavelets – 58.3tensile strength – 61.3tension – 62.2terabytes – 71.3Teracubes – 71.3terminal impedance – 58.5Tesla Bookstore – 67.6Tesla Coils video – 66.5Tesla Coil Builder’s Assn – 67.6Tesla, Nikola – 56.2, 67.6Tesla Society – 67.6TEX – 62.1, 62.6Texas Instruments – 55.6, 59.5, 66.3the edge – 57.1theater arts – 60.4theater lighting – 53.5thermal agitation noise – 57.4, 58.4thermal energy – 64.1thermal impedance – 68.2thermal inertia – 71.4thermo laws – 64.1, 64.4thermodynamic – 49.3, 53.1, 64.1thermodynamic cycle – 64.2thermoelectric – 68.1thermoelectric coolers – 68.1thermoelectric cooling modules – 68.1thermoelectric guidelines – 68.2thermography – 49.5Thomas Registry – 57.2, 69.2Thomson Consumer Electronics Publications – 50.2Thompson, Don – 51.5, 54.5, 66.53-D movies – 49.33-D Systems – 66.4threshold value – 59.4thumbscrews – 71.5tiling artifacts – 69.4timber management – 60.4time – 62.2time base corrector – 60.3time base correction – 60.2time code – 60.3time constant – 63.4Time Line – 53.5time sequence – 58.3time to breakeven – 64.4time value of money – 49.4, 63.5, 64.4timed output – 66.1Timmins/Kingsway – 60.4tinaja quest – 53.5, 57.2, 61.3, 66.5, 67.5, 71.3, 72.4tinaja questing – 57.1titanium dioxide – 53.2Toast and Coffee – 60.4Toaster – 49.5

toaster – 61.2ToasterPaint drawing program – 60.2tokenize – 66.1tokenized instructions – 66.1tone – 66.1, 71.1, 72.1tone decoder – 71.2tone encoder – 71.2tone signalling – 58.6, 71.1toner – 54.5Toner Transfer System – 54.5, 56.1TONERTRX.PS – 54.5top octave generators – 50.2, 50.3top secret gray map – 55.3Toshiba – 72.1touch tones – 71.1toy gyroscope – 58.2trade journals – 61.1, 62.5, 64.5Trade Winners – 59.7traditional photography – 70.1transducer – 63.1transform – 67.3transform plane – 56.4transformer – 61.4transient – 59.3transistor – 65.5translation – 67.1translator – 57.3transmission line components – 67.4transparency – 69.2transparancy schemes – 69.3transverse current – 70.5trapezoid – 67.2Trek – 68.5trellis modulation – 65.4triacs – 60.6tricks – 72.3Trident – 64.5Trimble Navigation – 67.1trinary cycle – 64.4triple distilling – 72.3TriQuint Semiconductor – 68.6Triumphs & Trials of an Organ Builder– 55.6Trophet C – 61.3TRW – 54.2, 60.6t-s diagram – 64.1, 64.4t-squared problem – 58.2TTL – 50.2, 52.1, 53.4, 59.5TTL Cookbook – 56.6, 60.6, 65.5, 70.6TTL monitors – 53.3tube sound – 72.5tune – 59.2Tuner’s Supply – 50.3tuning fork – 58.2, 58.3tunneling – 49.4

Hardware Hacker

xxiii

TV satellite – 51.5TV Technology – 60.6tweening – 58.3twinlead – 57.5, 67.4twisted film effects – 67.3two-dimensional transform – 67.1two-mast mount – 67.32N918 – 52.5two-point perspective – 67.2two-port buffer – 60.3two-set splitter – 67.3tye wrap – 59.6type approval – 61.4type-D clocked flip flop – 56.2typograhpy – 62.1, 62.3, 62.4

UFO crowd – 65.3UFO Magazine – 57.2UFO Marathon, The – 57.2UFO resource base – 57.2UFO resources – 57.5UFO stuff – 60.4UFO’s – 57.1ugly rumor – 65.2UHF – 65.5Ulano – 66.3Ulrich’s Periodical’s – 53.1, 69.2ultimate hacker’s language – 65.2ultra range FM antenna – 58.6ultrasonic cleaning – 63.2Ultrasonic Industry Mfg Assn – 63.3ultrasonic microphone – 63.2ultraviolet light – 66.3Ultrawave Explorer – 49.1UMI – 49.3, 53.1, 56.1underlying foundation – 64.1undersampling – 70.2unintelligent senators – 65.3Unitrode – 63.6universal hacker’s language – 68.4universal video interface – 51.2Untapped Technology in Review – 72.5unusual goodies – 53.5Up the Infinite Corridor – 68.6upper case – 69.2Usenet – 69.1utility lineman – 52.1

Vacuum systems – 64.1vacuum tubes – 58.1varactor diodes – 52.2, 52.4variable load – 65.2variable resistors – 67.4variables – 67.2

varistor – 50.2vector – 62.2, 70.4veggies – 63.6velocity – 58.2, 62.2verbose – 69.1vertical offset – 67.1vertical scale – 67.1vertical sync pulses – 60.2Vetta – 68.5VGA to NTSC – 63.1VHF – 65.5VHF amplifier – 57.5VHF/UHF amplifiers – 57.2VHS – 60.1, 60.3vibrating piezo structures – 58.3Victory Engineering – 58.6video – 65.1, 69.6, 71.3, 72.1video actor – 52.3video compression – 50.1, 54.1Video Data Handbook – 50.4video demo – 60.4video editing – 60.2video game – 58.6, 63.6, 66.1video game repair – 63.6video interface – 51.1Video Toaster – 60.1, 71.3Video Toaster User – 60.4video tracks – 60.1Video View – 64.5Videoimagescope – 72.5videotape – 59.6vinyl – 66.4vinyl sign cutter – 65.5, 66.2virtual reality – 65.5, 71.1VISA – 51.5viscosity – 62.5visual artifacts – 55.3, 69.4voice – 71.1voice email – 72.1voice messaging – 72.1voice recorder – 72.1Voice Synthesis LSI – 72.1Volara – 64.5Volextra – 64.5voltage – 65.2voltage regulator – 49.2Voltek – 50.4, 64.5voltmeter – 63.4volume control – 51.3, 53.4Vortec – 68.4vortex cooler – 68.4, 71.5vortex CPU cooler – 68.4Vox Humania Press – 55.6

Walker Scientific – 62.4, 70.6

warming curve – 68.3water hole – 65.4waterfalls – 70.3watt – 68.2Watt, James – 64.1watthour meter – 49.2wattmeter – 49.2, 65.2watts of cooling – 68.2wavelet – 49.1, 50.1, 56.4, 58.3, 71.3wavelet compression – 69.4, 71.3Wavelet Packet Library – 49.1wavelet shareware – 58.3wavelet transforms – 58.4WAVELET.PAK – 49.1, 50.2Wavelets & Their Applications – 50.1WAVELETS.PS – 58.4waving flag – 67.3weak magnetic fields – 70.4weather satellite – 56.6WeatherSat Ink – 56.6weaving – 60.4weaving loom – 69.6Wein Bridge oscillator – 71.4weird science – 70.1weird stuff – 53.5Well, The – wet cell battery – 53.2wetware correlation – 54.1white noise – 66.1Whole Earth Review – 53.2, 55.6, 56.1Whole Works – 62.6, 66.5, 72.5whoops – 53.1William of Ockham – 52.1Winegard – 58.5, 67.3wipes – 60.2wire EDM – 60.4wire gauges – 61.2Wired – 65.5wireless broadcasters – 52.2wireless communication – 65.4Wireless Communication IC Summary – 70.6Wireless Design & Development – 68.6wireless mice – 65.5wireless modem – 64.5word processor – 59.3, 62.4World Cogeneration – 64.4work – 64.2, 64.3working fluid – 64.1, 64.3workpiece – 60.4, 63.6

X position – 56.3XA-7A – 50.1, 52.3, 52.5, 53.1Xerox-of-an-Xerox – 56.2

Hardware Hacker

xxiv

XMODEM – 62.6, 69.3X-ray – 61.1, 68.6

Y position – 56.3Yagi – 57.3, 57.4, 58.5Yagi antenna – 58.6Yagi Antenna Design – 58.6Y-C video – 51.4Your Hit Parade – 65.4yuppy surplus resellers – 67.1

Zener – 52.4zener diode – 49.3zero point scalar energy – 56.1, 67.6zero royalties – 66.2zero slope – 65.3Zilog – 61.5Zimmer Foundation – 53.2Zlink 1900 – 58.4zoom – 50.1

GEnie

IMAGEKIT.PS – 56.3, 56.5, 69.5SPOTLESS.PS – 70.4

084 FRACTFRN.PS – 69.5162 NOPATENT.TXT – 53.2186 DISTILL.PS – 72.4335 SECRTEMP.GPS – 59.4336 FASTFERN.PS – 69.5337 STARTUP.PS – 66.2, 69.5365 WAVELET.PAK – 49.1, 50.2367 SMITHCHT.PS – 49.1, 59.4387 POSTVECT.PS – 66.2388 LASGNOTE.TXT – 56.4397 HACKFG51.PS – 51.2401 PRNCRCT.GPS – 53.3, 53.5, 54.5, 59.4410 BOOKDEMD.PS – 55.1411 BOOKDEMD.TXT – 55.1419 NUTS3.PS – 53.5, 54.5427 AUTOCORR.PS – 54.3451 LASGCAL.PS – 56.4460 SPEEDUP.PS – 59.4, 69.5, 72.4463 LENA.PS – 55.5, 56.3, 56.5, 69.5464 MANDRILL.PS – 69.5465 WAVELETS.PS – 58.4468 LENAHIST.PS – 55.5, 56.6, 69.5477 NOPATENT.PS – 59.7484 HACK56.TXT – 69.5485 HACKFG56.PS – 69.5494 EMERGOP2.PS – 58.4511 NUTS9.PS – 59.4515 FONTELIM.PS – 72.4

517 GONZO15.PTL – 59.4, 62.4520 INVENORG.PS – 59.7522 FMYAGI.PS – 57.3523 NUTS10.PS – 60.6588 FUZZYBEZ.PS – 62.4751 EXERCISE.GPS – 68.6753 FERMAT.TXT – 69.1769 STR2FILE.PS – 69.5779 RETOUCH.PS – 70.4785 HACK69.PS – 69.5

Hardware Hacker

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