picking & planning a project… test & debug basics from classes ee182 & ee183 prof....

Picking & Planning a Project…Test & Debug Basics

From Classes EE182 & EE183Prof. Tamara Schmitz

“Dr. T” and Ty

Outline

•Six-Pack of Bad Assumptions

about Senior Projects

•Sample Engineering Division of

Labor

•Defining a Project

(Importance of Test)

•Helpful Hints

•Debugging Strategies

•Project Ideas

Six-Pack of Bad Assumptions


1. The Project will be defined for me.

This is NOT a homework assignment or class project

This is YOUR SENIOR PROJECT.Instead of solving someone else’s problem, you have the challenge of…1.discovering a problem

2.defining it for yourself3.breaking it into manageable (and

testable) chunks4.designing/building/testing these chunks5.integrating them into a product6.improving/refining/packaging7.quantifying success8.presenting your work

EE198A

EE198B


2. The Project will be neat/clean/easy.

On the contrary, your project will most likely be messy.

You will have to try multiple configurations to successfully build a circuit.

There is a large gap between theory and practice.

Will it work just because you designed it?

How good is your design?How realistic are your models if you simulate?How good are your components? (% tolerance)

How good is your assembly?


3. Friends make the best project partners.

Hanging out and working together are very different.

Choose partners for their:Talent or Special Skills (RF, software)

Communication abilityComplementary skills

DedicationAbility to commit time

Other things important to you…


4. More group members means less work for me.

This is NOT a LINEAR relationship.

2 people 50%YOU + 50%ME OR

3 people 33%YOU + 33%ME + 33%OTHER

It’s more like

2 people 75%YOU + 75%ME OR

3 people 65%YOU + 65%ME + 65%OTHER

(& that’s only if everyone contributes equally… rare.)


5. “I’m about to graduate with an EE degree, so whatever I design and build will just work.”

The nature of a project is more than design; It is also implementation!

This is not something you have a lot of practice or experience with. You absolutely MUST plan for time to learn, time to

make mistakes, time to bang your head on the wall. Making a project work means you have taken EVERY important issue

into account.

So… save lots of time to debug and improve your project. Set deadlines early. Don’t let them slip.

If they slip, make up the workto get back on schedule.


6. My group will break up work into analog, digital, and software parts.

This only breaks up the design work!

There is SO MUCH MORE to completing a project.

Allow me to offer an alternate plan,based on the structure in the IC industry…

Engineering Division of Labor

Test

Design

Marketing

ApplicationsProduct


Test

Design

Marketing

ApplicationsProduct

Design deals with theory.They run simulations and improve models.

They innovate.They built what has never been built

before.


Test

Design

Marketing

ApplicationsProduct

Applications demonstrate the usefulness of a design.

They evaluate the competition, find 2nd sources for parts, help customers debug problems,

write articles and develop improvements for projects.


Test

Design

Marketing

ApplicationsProduct

Test engineers are in charge of evaluation of the design, fab, and assembly process. Their strongest skills are in debugging—hardware, software, interfaces, equipment limitations.

(more later)


Test

Design

Marketing

ApplicationsProduct

Sales and Marketing engineers interface between a company & its customers. They build relationships, make presentations and make the sale. They return feedback from the customers

to the rest of the team.

$$$$ $

$$ $


Test

Design

Marketing

ApplicationsProduct

Product engineers are devoted to a particular project. They make sure everyone else is doing their job efficiently and on-time, to ensure the

company will make money. They analyze yields, synthesize large amounts of data and coordinate

subcontractors.


Test

Design

Marketing

ApplicationsProduct

How could this apply to your project?(Assuming group of 3, students A, B, and C)

(Entire Group—A,B,C)

(Project Lead-B)(Hands-on, Methodical-

A) (Make sure it works like the customer

wants-C)


Test

Design

MarketingApplications

Product

(Entire Group—A,B,C)

(Project Lead-B)(Hands-on, Methodical-

A)

(Make sure it works like the customer

wants-C)Makes sure design can be verified and

operation quantified.

Understands multiple interfaces

(analog/digital, software/hardware)

Detail-oriented.Calm demeanor.

Organize meetings.Enforce

deadlines.Enable group

members.Evaluate alternate solutions.

(cheaper/faster/better?)

Take personal responsibility for

success of project.

Investigate competition. Order parts.

Find 2nd sources.Point person for

assembly.Make back-up

plans.Develop

improvements.Consider

packaging (customer interface).

Finding & Defining a Project

Where do we start???

Finding & Defining a Project

•The internet•Professors have interesting

(weird?) ideas•Ask friends what they need or

would like to have•Ask your mom•Ask a 5 year old•Use IEEE resources•Brainstorm•Call tech support at a company where you want to work and ask for an idea•Identify EE impact on various professions (firefighter, teacher, vet, gardener, brick layer…)

Narrowing down the List1.Sit down with your group2.Let each member pick 3 favorites and 3

non-favs3.Compare notes and agree on 3 ideas to

focus on

Before approaching an advisor, construct a block diagram of each of the 3 project ideas.

1.What will each project involve?

2.What are the trade-offs in your design?

3.What competition exists for your product?

4.Check on the availability of parts

5.If unsure about operation, build functional prototypes to verify ideas

Setting your Plan of Action

• Find an Advisor• Be prepared• Share business plan and backup plans• Clarify requirements and expectations

• Get Going• I encourage my students to have part of their design built by the end of EE198A to show viability of design.• Trouble hides in strange places. You need to dive in to find it and handle one issue at a time.

Design with Test in Mind

• How are you going to prove that your project works? (What if only parts of it work?)

• Include measurement access points

• Document testing and share with advisor

• As you build pieces to test, keep working sections in a safe place.

• Build a copy if you want to improve/mess with the design. If you ruin it, you’ll still have the original. (Helps in debugging to have a comparison.)

Stages of Prototyping

1.Simulation

Quality of modeling (ideal?)

2.Breadboard

Frequency limitations

1pF between adj. holes

3.Protoboard (soldered breadboard)

4.Printed Circuit Board (PCB)

~ $50 to $500

Test Each Block in theBlock Diagram1.Test circuits early

2.Test sections one at a time

3.Test sections in pairs (watch for

loading)

4.Test complete design

Don’t wait until Presentation Week to start testing! Get a simple

prototype as quickly as possible.

Helpful Hints

Helpful Hints

Bypass Capacitors on every chip near power supply pinon power supply (even if using

batteries)across motor terminalsuse ~ 1F or more

Label wires/Use color codes

Breadboards can have hidden shorts

Chips burn out (buy extras)

Surface-mount parts are difficult to

work with

(packages: DIP, SMD, BGA, axial,

0805)

Use sockets when possible

More Helpful Hints

Batteries have issuesseries resistancemaximum current deliverable

(much less than the bench power supply)

voltage decreases with use

Use Voltage Regulators (ex: LM7805)

AC power is not DC voltage

Single-supply vs. Dual-supply ICs

Ground planes

Helpful Places for Parts

Halted Specialty Corporation (

www.halted.com)garage-sale of electronic parts10% discount with student IDhelpful staff (Dr. T’s favorite EE place!)

Anchor Electronicssmaller selection, better organized than Halted

Fry’s – be careful of returns/opened boxes

Digikey – parts supplier (www.digikey.com)

Mouser – parts supplier (www.mouser.com)

Local IC Companies – free samples (order

EARLY)

Debugging a Circuit

Debugging a Circuit

1.Check connections with continuity on DMM

2.Turn on power3.Check DC bias levels4.Apply simple test signal (like 1kHz sine

wave)5.Check signal with scope through signal path6.If there is a problem, test one stage at a time

driving problem? (prev stage not strong enough)

loading problem? (need a buffer)7.Use ONE hand–is something really hot?

too much currentlower current or add a fan

Debugging a Circuit

Remember the basics:

• Series or Parallel connections• Thevenin and Norton equivalents• Are you measuring a voltage or a current?• Op Amps can only be stable with negative

feedback.• Don’t expect voltages beyond the power

supply.• Use logarithmic and/or not linear steps

Debugging a Circuit

The first step to finding a problem is to locate it.

Verify as many blocks as possible.

Probing signal nodes and looking for a change help you find sensitive places.

Example: add capacitance to one node at a time and watch for the frequency of some unwanted

ringing to change.

(FYI: Finger is a convenient capacitance.)

Debugging? What doesn’t work?

Tester/Equipment

DUT or component

Board and Connections

Software

Be SystematicBe PatientCheck and Recheck

Is there Power?What is the Bias?Follow the Signal…

Simple Debug Steps Summary Verify power and grounds Verify inputs and outputs against

data sheet norms Verify mechanical components

(wires) Check for physical shorts and opens

Use ohm meter Visual inspections

Check for missing or wrong components Check for heat, smoke & fire

A Few Project Ideas

A Few Project Ideas

Two Favorites from Last Year

Windspeed Monitor for BridgesSum of ClassesMechanical IssuesMultiple TransmittersDigital/Analog/RF“Elevator Description”

Digital Picture FrameFPGA10-layer PCBAuto-correction for small filesBuilt-in MP3 player, too

A Few Project Ideas From Me

• Test Equipment using USB on laptop• Interview doctors, librarians, umpires… what would they like?• Designs to help 3rd world communities

The End

Good Luck!!!

picking & planning a project… test & debug basics from classes ee182 & ee183 prof....

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