1 observation student

8/12/2019 1 Observation Student

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You have observed something.

Do you know why youre seeing what youre seeing ?

And why ?

Even during visual fixation of a stationary target, our eyes perform

rather erratic miniature movements, which represent a random walk.

These fixational eye movements counteract perceptual fading, a

consequence of fast adaptation of the retinal receptor systems to

constant input.

The most important contribution to fixational eye movements is

produced by microsaccades;


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Participation in class

A few in-class exercises

Building some electrical circuits

What we are going to do.

Explore topics common to all fields of engineering

See how engineering affects yourlife

Study a little Electrical Engineering

Study a little Computer Engineering

Well use nothing beyond grade school arithmeticand a little high school geometry.

Oh yes! Also a little common sense.


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Engineers solve problems, improve lifeby using existing science and materialsto engineer new products and systems.

Design solutions with a maximum ofsuitability and safety and a minimumof cost and materials.

Scientists try to discover new things.New chemical, drug, food flavoringNew materialsNew physical lawsetc

Difference between a scientist and an engineer.

How does an engineer answer the question ?

Lets do a little quiz to see how observant we are.


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Observing things and understanding why is fundamental to engineering.

From experience, you get ideas of how to solve future problems.


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Why is the sky blue ?

Why is it red ?


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By the time it passesthrough all that

atmosphere, all the blueis gone.

Sunset Orange

Knowing why the sky is blue has benefits.

Helps designers of eyeglasses

Instruments for astronomers (starlight must pass thru atmosphere)

The Hubble telescope

Thermal glass for houses

Safety glass for autos

Added benefit of knowing some geometry about the 3rdrockfrom the sun.


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The Raytheon Story

Re-entry causes bow shock of ions

Cold War fear of MIRVs.

De-orbit starts over China to hit US

Unambiguous range accuracy of 2 meters at 4,000 miles

Government asked, Raytheon proposed, Government awarded contract

In todays dollars about $100 Million. Atomic clock; Huge power

From an engineering perspective, did this contract make sense ?

not to scale

Lets park a boat half way between Hawaii and Japan, Thats about4,000 miles from China

Lets park there and look out (straight line) 4,000 miles

Boat


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Drawings are to scale

How did I benefit ?

While were on subjects Earthly

A person has just thrown a ball up in the air at about a 60 degreeangle. It goes up, arcs, peaks, and falls to the ground.

Draw a ball in the lower left corner of a page.

Draw a series of balls along the complete trajectory.

Now, for each position of the ball draw arrows to show what sorts of forcesare acting on the ball, both the strength and direction of those forces.

If a force becomes greater, use progressively larger arrows.If a force becomes smaller, use progressively smaller arrows.


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Still on subjects Earthly

Lets see what you were taught.

Write a paragraph or two explaining why thereare seasons on earth. You might include somedrawings to illustrate your argument.


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Cowboys & Stagecoach Wheels

What, physically, is a movie ? How do they work ??

Street lights - Mercury vapor or Sodium vapor


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Voltage and Current

Information is generally processed as a changing voltage over some period of time

Temperature to voltage driving meter

Just like water pressure and resulting flow (current)

Show that vapor lights go completely dark 120/sec (Howoscilloscope works)

Use signal generator to

show voltage v time

also frequencies & how to

measure them


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low frequency

high frequency

Just like white lightcombination of constituent freqs

Use the prism to separate white light into its constituent colors

Shine colors onto same spot combines them back to white

Lets look at doing the same with voltage signals

Put multisim demo of this here


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Talk about frequency content (so much of this frequency, so much of that)

Microphone converts air pressure variations into voltage variations

Voltage vs Time


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Voltage vs Time

ee ah

Analog - Digital


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Sampling theorem

Sample at a rate that is twice the highest frequency in the signal, you

can absolutely recover the original signal

Highest freq is 3,500 - so, digitize 7,000 per second.

Need a new number every 143 millionth of a second. of 143 usec

A day is a short amount of time for humans

After birth, takes around 6,000 days before you have kids

Takes 265 days gestation

27,000 days = 1 life time.

Some insects stuff whole lifetime into one day !

For electricity, 1 microsecond is a very long time.

If I transmit each number for 1 usec, I can put 143 calls on the

same wire.

Make use of this effect - Multiplexing

If I transmit numbers for1 usec, I can put 143 callson the same wire.


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Multiplexing

7-segment Display


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Multiplexing part 2


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Some of the best stuff comes from failures


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Modern penicillin- Blue-green mold

In 1948, Sir Alexander Fleming was tryingto grow bacteria (staphylococcus),

and something kept killing his cultures.

Penicillin was in use much earlier. Any guesses ?

At least as early as the US Civil War


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Its been known for many centuries thatdung from animals thateat a lot of grass is somewhat antibacterial when rubbed in anopen wound.

Again, my question is who first said Gee Ralph, thats a nastylooking stab wound you have there, lets rub some

My guess is that early farm type people noticed that their footwounds did not get infected very often and they observed that theyfrequently walked in cow droppings. They put 2 and 2 together.

The ancient practice of using maggots to clean burn wounds is re-emerging in western medicine. How was this discovered ?

The question that Ihave absolutely no ideahow to answer is :

Who first said Gee, Bob,

Failure Observation - Imagination


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You dont have to be Albert Einstein to be successful andproductive (in Engineering).

One summer day in 1948, George de Mestral as Swiss amateur

mountaineer and inventor decided to take his dog for a nature walk.

The success of de Mestral resulted from

1) being observant,2) being imaginative (creative) and3) having a knowledge of materials.

It had nothing to do with specific school subjects.


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All warfare is based on deception.

Never take what your enemy offers.

Politics, the media, and winning debates

Purposeful mis-representation will bias your understanding/beliefs.


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Sensationalism think the greenhouse effect

To effectively communicate we need;

Common terms

Standard definitions

Well defined units


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Mercator Projection map throughout our school systems.

There is no intent to mislead here, but mislead it does.

If only subconsciously, most people equate size with significance or importance.

Greenland 0.8 million square miles

Africa 11.6 million square miles


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Sweden/Norway 322,478 square miles

Mexico 761,600 square miles

Alaska 322,478 miles2

Australia 2,968,000 miles2


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Its unlikely that any two things in the universe are exactly the same.

In engineering, how close to being the same is close enough?

Interchangeable parts for an assembly line. Say, 2.143 0.001 inches?

What definitions do we use for units?

For example; How long is a day (for simplicity, at the equator)?

So, How long is a day?


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For example; How much do you (or anything else) weigh?

If you stand on a very accurate scale at the equator,you will weigh more at noon than at midnight.

Engineers must be very specific regarding all factors that influence.

How long is a second? Ask NIST.

We get more accurate as theyears go by.

Current standard is 1 second in 60 million years.

Time standards are particularly important inelectrical and computer engineering.


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Why we care about very accurate time standards.

Triangulation is a basic engineering technique.

GPS has become an integral part of our everyday life.

Signal travels 12,500 to 16,000 miles@ 186,000 miles/s

To determine distance within 10 ft,need to have time correct to within0.000,000,01 of a second.

That requires a primary time standard(atomic clock).


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Good engineers develop keen observation skills

Multiplexing images or voltage signals in time

Frequency content of a signal (also the Sampling Theorem)

There is sometimes great value in failed experiments

Be aware that information can be communicated so as to mis-lead

Units can be tough to nail-down

We live in a world saturated with products ofElectrical and Computer Engineering

1 observation student

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