Printed Circuit BoardPrinted Circuit BoardAnarchy DriveByAnarchy DriveBy

ITP - November 13, 2006ITP - November 13, 2006

Nick Sears – Nick Sears – http://jamesnsears.comhttp://jamesnsears.com

Michael Ang – Michael Ang – http://michaelang.comhttp://michaelang.com

What we’re going to doWhat we’re going to do

Comparison of prototyping Comparison of prototyping techniquestechniques

Designing a boardDesigning a board Schematic captureSchematic capture Board layoutBoard layout

What we’re going to do What we’re going to do (contd)(contd)

Making a boardMaking a board Output file generationOutput file generation Online fabricatorsOnline fabricators DIYDIY

Resources and linksResources and links Surface-mount soldering demoSurface-mount soldering demo

Breadboard vs Breadboard vs Protoboard vs Printed Protoboard vs Printed

Circuit BoardCircuit Board

BreadboardBreadboard

Fast!Fast! Susceptible to Susceptible to

vibration, droppingvibration, dropping Can document with Can document with

good photogood photo Easy to debugEasy to debug

BreadboardBreadboard

Being neat is worth it!Being neat is worth it!

(don’t do this)(don’t do this)

ProtoboardProtoboard

Cheap!Cheap! Slower than Slower than

breadboardbreadboard Hard to capture Hard to capture

layoutlayout Good reliabilityGood reliability Thought Thought

required while required while assemblingassembling

Circuit boardCircuit board

More startup cost/timeMore startup cost/time Good debuggingGood debugging Easy to make more Easy to make more

boardsboards Good reliabilityGood reliability Good for Good for

communicating designcommunicating design Smallest!Smallest!

Design StepsDesign Steps

Schematic captureSchematic capture Board layoutBoard layout

Schematic captureSchematic capture

Add partsAdd parts Connect parts (create “nets”)Connect parts (create “nets”) Create new devices (if necessary)Create new devices (if necessary) Electrical Rule Check (ERC)Electrical Rule Check (ERC)

Board DesignBoard Design

Create board from schematicCreate board from schematic Place componentsPlace components Route tracesRoute traces Design Rule Check (DRC)Design Rule Check (DRC)

Common sizesCommon sizes

Check with board house for available drill Check with board house for available drill sizes and trace widthssizes and trace widths Some provide DRC file for EagleSome provide DRC file for Eagle

HolesHoles Vias - 20 mils (or smallest from board house)Vias - 20 mils (or smallest from board house) Holes - ~50 milsHoles - ~50 mils

TracesTraces 10 mils (larger for power and where possible)10 mils (larger for power and where possible)

Board LayersBoard Layers

Top – top traces and SMT padsTop – top traces and SMT pads Bottom – bottom traces and SMT padsBottom – bottom traces and SMT pads Pads – through-hole component legsPads – through-hole component legs Vias – connect top and bottom signalsVias – connect top and bottom signals Dimension – outline of boardDimension – outline of board tPlace, (bPlace) – silkscreentPlace, (bPlace) – silkscreen tStop, bStop – soldermasktStop, bStop – soldermask (And a few more layers, e.g. for (And a few more layers, e.g. for

autorouter)autorouter)

Generate Output FilesGenerate Output Files

Generate Gerber filesGenerate Gerber files Generate layer imagesGenerate layer images

Sample PricingSample Pricing

Most do boards up to a given size, or Most do boards up to a given size, or full panelfull panel

Can put multiple designs or copies on Can put multiple designs or copies on a single board/panela single board/panel Fabricator charges to score or cutFabricator charges to score or cut

Group orders a good ideaGroup orders a good idea

Sample Pricing Sample Pricing (contd)(contd)

http://batchpcb.comhttp://batchpcb.com $10 + $2.50/sq in (cheapest for small $10 + $2.50/sq in (cheapest for small

boards)boards) Wait while orders are batchedWait while orders are batched Shipping included (n weeks, where n=??)Shipping included (n weeks, where n=??)

http://goldphoenixpcb.bizhttp://goldphoenixpcb.biz $120 for 14.5x10” panel$120 for 14.5x10” panel Shipping included (~1 week)Shipping included (~1 week) Depanelize??Depanelize??

Sample Pricing Sample Pricing (contd)(contd)

http://custompcb.comhttp://custompcb.com 2x 4x5.5” for $582x 4x5.5” for $58 $12 shipping$12 shipping De-panelize for $.50/pieceDe-panelize for $.50/piece

Advanced Circuits Advanced Circuits (http://www.33each.com/)(http://www.33each.com/) $33 for 60 sq in (min 1 with student $33 for 60 sq in (min 1 with student

special)special) Not sure about shippingNot sure about shipping

DIY Board EtchingDIY Board Etching

ITP Board Etching Tutorial ITP Board Etching Tutorial (thanks Todd!)(thanks Todd!)

Use laser printer to print top and Use laser printer to print top and bottom layersbottom layers

Transfer toner to copper clad boardTransfer toner to copper clad board Etch away excess copper using FeClEtch away excess copper using FeCl

Put in Hazmat when done!!!!Put in Hazmat when done!!!! Drill holesDrill holes

Next StepsNext Steps

Design a boardDesign a board Get it fabricatedGet it fabricated Make a nice enclosureMake a nice enclosure Have your projects travel the worldHave your projects travel the world Sleep soundly at nightSleep soundly at night

ResourcesResources

Blog post will be updated: Blog post will be updated: http://www.michaelang.com/a/102/prhttp://www.michaelang.com/a/102/printed-circuit-boards-driveby.htmlinted-circuit-boards-driveby.html

Questions?Questions?

Nick Sears – Nick Sears – http://jamesnsears.comhttp://jamesnsears.com

Michael Ang – Michael Ang – http://michaelang.comhttp://michaelang.com

(Stick around and watch Nick (Stick around and watch Nick solder!)solder!)