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There are a wide variety of techniques used in electronics. | There are a wide variety of techniques used in electronics. | ||
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− | == | + | == Printed circuit board design/fabrication == |
− | + | === Overview === | |
+ | === Software Design === | ||
+ | See [[#Software_design_tools|Software Design Tools]] below. | ||
− | * [[Solderless protoboard]] | + | ==== Step by Step by using Software Design Tool ==== |
+ | *make sure the dimension and shape of PCB | ||
+ | *make sure the size and location of Via for PCB stand | ||
+ | *Make sure each components footprint. | ||
+ | *each components are placed on suitable place by put on a hardcopy of simulation PCB | ||
+ | *All components get enough clearance between them. | ||
+ | *Silkscreen layout is confirmed. | ||
+ | *PCB is drawn. | ||
+ | *silkscreen adding the following: | ||
+ | **version no. | ||
+ | **organization name | ||
+ | **board name | ||
+ | *Netlist is ran and got a no error result. | ||
+ | *DRC is ran and got a no error result. | ||
+ | *Overall is checked. | ||
+ | *generate Gerber and send to [[PCB Manufacturers]]. | ||
+ | |||
+ | === Manual Design === | ||
+ | Somepeople do this with layout on clear film or by directly drawing on a circuit board, of even by scratching, grinding.... For now let them google this. | ||
+ | |||
+ | === Homebrew fabrication === | ||
+ | Before exploring these techniques, you should understand your options with regard to services such as BatchPCB.com, ExpressPCB.com and PCB123.com. Being able to have several boards fabbed in 2 days for $59 (for example) makes it harder to justify the hassle of etching your own boards at home. | ||
+ | * [http://www.electricstuff.co.uk/pcbs.html "How to make really really good homemade PCBs"] by Mike Harrison 2007 | ||
+ | * [[Toner Transfer]] -- This method involves laser printing your PCB design onto paper, then transferring toner onto copper-clad board. | ||
+ | * [[Photoetching]] -- Exposure of PCB designs onto photosensitized copper-clad board. | ||
+ | * [[Chemical Etchants]] | ||
+ | * [http://groups.yahoo.com/group/pcb-gcode "Mechanically etching or milling PCBs. No chemicals!"] -- Use your CNC router/mill to make PC boards. | ||
+ | * [http://openfarmtech.org/index.php?title=Routed_Circuit_Board Open Source Ecology wiki: "Routed Circuit Board"] | ||
+ | * [http://tech.groups.yahoo.com/group/Homebrew_PCBs/ Yahoo group: Homebrew_PCBs · Homebrew Printed Circuit Boards] | ||
+ | |||
+ | === Commercial PCB fabrication === | ||
+ | * [[Submitting PCB's for fabrication]] -- Common processes for submitting PCB's for fabrication. | ||
+ | * [[PCB Manufacturers]] | ||
+ | * [http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A30196 "PCB fabbing advice"] by Chris Anderson 2008 | ||
+ | |||
+ | ==Best Practices for PCB Layout== | ||
+ | ===Theory=== | ||
+ | *Provide the easiest path (lowest impedance) for current to flow | ||
+ | **Return current tends to flow directly under signal trace (for PCB having ground plane) | ||
+ | **Inductance increases with length of traces | ||
+ | **Inductance increases with the area enclosed by by signal trace and ground | ||
+ | *Prevent digital currents from contaminating analog currents | ||
+ | |||
+ | ===Design=== | ||
+ | *Partition PCB into "analog stuff" and "digital stuff". | ||
+ | *No digital signal traces should cross over analog ground, and vice versa | ||
+ | *For components having both analog and digital signals (e.g. ADC), orientate components so that the analog signal traces goes only over the analog ground plane, and digital signal traces goes only over the digital ground plane | ||
+ | *AGND and DGND of ADC must have a small impedance (i.e. separated by short distance) | ||
+ | *Add decoupling capacitors close to Vcc and DGND of ICs | ||
+ | *Add ferrite beads and capacitors (PI-filter) to power rail for low-pass filtering (reduce ripples). | ||
+ | |||
+ | ===Routing=== | ||
+ | *Place fixed components first (components location that cannot be changed, e.g. connectors, buttons, etc) | ||
+ | * Make installing parts onto the PCB fast: | ||
+ | ** Fastest: No through-hole parts. All surface-mount parts on the bottom side. | ||
+ | ** Next-fastest: All through-hole parts on the top side. All surface-mount parts on the bottom side. ( [http://www.psocdeveloper.com/articles/apple-mighty-mouse-spills-its-guts/the-capacitive-touch-sense-buttons-pcb.html "Mighty Mouse Main Printed Circuit Board (PCB)"] ) | ||
+ | *Separate components into groups | ||
+ | **Digital signals only | ||
+ | **Analog signals only | ||
+ | **Digital and analog (Mixed) signals | ||
+ | **High current devices (e.g. led backlight for LCD/buzzer) | ||
+ | *Do not partition ground into analog and digital planes. | ||
+ | **Use a single ground plane. See the "[[#References | Grounding References]]" below. | ||
+ | *Orientate components that have mixed signals according to the orientation of the ground planes, and straddle components over DGND and AGND | ||
+ | *Place digital only components over DGND | ||
+ | *Place analog only components over AGND | ||
+ | [[File:Pcb layout.png|thumb|800px|center|Grounding Example for PCB]] | ||
+ | *Decoupling capacitors should be as close to the ICs as possible | ||
+ | Vcc | ||
+ | | | | | | | ||
+ | +-----------+ | ||
+ | -------+-+--|-+---------|-------- Vcc | ||
+ | |C| | IC | | ||
+ | -------+-+--|---------+-|-------- GND | ||
+ | +-----------+ | ||
+ | | | | | | | ||
+ | GND | ||
+ | *Lay critical (noise-sensitive) traces first (e.g. crystal, analog signals) | ||
+ | **As short as possible | ||
+ | **Use 45<sup>o</sup> turnings instead of 90<sup>o</sup> | ||
+ | *Paired signal traces (e.g. TX+, TX- in ethernet chips) should run parallel along each other | ||
+ | TX+ -----\ | ||
+ | TX- ----\ \ | ||
+ | \ \ | ||
+ | \ \ | ||
+ | \ \ | ||
+ | \ \------------ TX+ | ||
+ | \------------- TX- | ||
+ | |||
+ | ===References=== | ||
+ | *Grounding | ||
+ | **[http://www.hottconsultants.com/pdf_files/june2001pcd_mixedsignal.pdf Partitioning and Layout of a Mixed Signal PCB]: The importance of single ground plane and partitioning of analog and digital signal trace | ||
+ | ** [http://techref.massmind.org/techref/noises.htm#unsplit_ground Massmind Techref: "Unsplit ground"] | ||
+ | **[http://www.hottconsultants.com/pdf_files/ground.pdf Ground- A Path For Current Flow]: The importance of decoupling capacitors | ||
+ | **[http://www.ece.msstate.edu/courses/ece4512/des1_syllabus/current/PCB_Layout_Tips.ppt PCB Layout Tips]: a power point presentation | ||
+ | **[http://pemclab.cn.nctu.edu.tw/w3news/%E6%8A%80%E8%A1%93%E5%A0%B1%E5%91%8A/TR-040.%E9%9B%BB%E8%B7%AF%E6%9D%BF%E4%BD%88%E5%B1%80%E5%8E%9F%E5%89%87/html/layout.htm PCB Layout Guidelines]: in Traditional Chinese | ||
+ | *Crystals and Oscillators | ||
+ | **[http://www.atmel.com/dyn/resources/prod_documents/doc8128.pdf AVR186]: Best Practices for the PCB layout of Oscillators | ||
+ | *ADC & Analog Filters | ||
+ | **[http://ww1.microchip.com/downloads/en/DeviceDoc/adn007.pdf ADN007]: Techniques that Reduce System Noise in ADC Circuits | ||
+ | **[http://ww1.microchip.com/downloads/en/DeviceDoc/ADN010.pdf ADN010]: Predict the Repeatability of your ADC to the BIT | ||
+ | **[http://ww1.microchip.com/downloads/en/AppNotes/00699b.pdf AD699]: Anti-Aliasing, Analog Filters for Data Acquisition Systems | ||
+ | **[http://ww1.microchip.com/downloads/en/AppNotes/00682c.pdf AN682]: Using Single Supply Operational Amplifiers in Embedded Systems | ||
+ | **[http://ww1.microchip.com/downloads/en/AppNotes/00990a.pdf AN990]: Analog Sensor Conditioning Circuits - An Overview | ||
+ | *EMC | ||
+ | **[http://www.atmel.com/dyn/resources/prod_documents/doc1619.pdf AVR040]: EMC Design Considerations | ||
+ | **[http://www.freescale.com/files/microcontrollers/doc/app_note/AN1705.pdf AN1705]: Noise Reduction Techniques for Microcontroller-Based Systems | ||
+ | ** [http://www.st.com/stonline/books/pdf/docs/4988.pdf AN898: EMC general information] | ||
+ | ** [http://www.st.com/stonline/books/pdf/docs/4967.pdf AN901: EMC guidelines for microcontroller-based applications] | ||
+ | ** [http://www.st.com/stonline/books/pdf/docs/9914.pdf AN1709: EMC design guide for ST microcontrollers] | ||
+ | |||
+ | == Circuit construction (Prototyping - Other than custom PCB) == | ||
+ | |||
+ | * [[Solderless protoboard]] ([http://en.wikipedia.org/wiki/Breadboard Wikipedia:Breadboard]) ([http://www.best-microcontroller-projects.com/prototyping.html a simple example with a small microcontroller]) | ||
* [[Point-to-point]] ([http://en.wikipedia.org/wiki/Point-to-point_construction Wikipedia:Point-to-point construction]) | * [[Point-to-point]] ([http://en.wikipedia.org/wiki/Point-to-point_construction Wikipedia:Point-to-point construction]) | ||
* [[Wirewrap]] ([http://en.wikipedia.org/wiki/Wire_wrap Wikipedia:Wire Wrap]) | * [[Wirewrap]] ([http://en.wikipedia.org/wiki/Wire_wrap Wikipedia:Wire Wrap]) | ||
* [[Dead bug style]] | * [[Dead bug style]] | ||
− | * [[Manhattan style]] | + | * [[Manhattan style]] aka [http://ciphersbyritter.com/RADELECT/BREADBD/BREADBD.HTM "A Modern Breadboarding Technology: Insulating Pads Soldered to a Ground Plane"] |
− | + | ||
− | + | [[http://www.techlib.com/electronics/construction.html "Construction Ideas"]] has nice photographs of the above circuit construction techniques. | |
− | [http://www.techlib.com/electronics/construction.html "Construction Ideas"] has nice photographs of the above circuit construction techniques | ||
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* [[Stripboard]] (Veroboard): ([http://en.wikipedia.org/wiki/Stripboard Wikipedia:stripboard].) | * [[Stripboard]] (Veroboard): ([http://en.wikipedia.org/wiki/Stripboard Wikipedia:stripboard].) | ||
− | + | == Soldering techniques == | |
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* [[Basic soldering]] -- How to use a soldering iron. | * [[Basic soldering]] -- How to use a soldering iron. | ||
* Surface Mount | * Surface Mount | ||
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** [http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/302_jumper%20wires.html official NASA recommendations for adding discrete wiring ("jumper wires") to PCBs] | ** [http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/302_jumper%20wires.html official NASA recommendations for adding discrete wiring ("jumper wires") to PCBs] | ||
− | (Have you seen this [http://hackaday.com/2007/06/04/cnc-solder- | + | (Have you seen this [http://www.hackaday.com/2007/06/04/cnc-solder-paste-pick-n-place/ CNC solder paste/pick n place] ?) |
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− | + | == [[Hardware tool]]s == | |
− | + | A directory of [[hardware tool]]s that you may find useful. | |
− | == [[ | + | == [[software tool]]s == |
− | + | == Software design tools == | |
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A directory of [[software tool]]s that you may find useful. | A directory of [[software tool]]s that you may find useful. | ||
+ | |||
== [[PC-Microcontroller Communications]] == | == [[PC-Microcontroller Communications]] == | ||
+ | |||
Discussion of the various methods to connect a microcontroller or embedded system to a PC... | Discussion of the various methods to connect a microcontroller or embedded system to a PC... | ||
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Humans writing a program almost always do it in a language. Here is a section that discusses some of these languages: [[Programming Languages]] | Humans writing a program almost always do it in a language. Here is a section that discusses some of these languages: [[Programming Languages]] | ||
− | == | + | == Enclosure == |
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* The Earth Signal should short to whole metal Case | * The Earth Signal should short to whole metal Case | ||
* Digital/Analog GND should separate to this Earth Signal, and should connect a Y-cap. to filter the noise between them. | * Digital/Analog GND should separate to this Earth Signal, and should connect a Y-cap. to filter the noise between them. | ||
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== Misc Tips Tricks == | == Misc Tips Tricks == | ||
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[[Misc Tips Tricks]] | [[Misc Tips Tricks]] | ||
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== Further Reading == | == Further Reading == | ||
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* [http://airborn.com.au/method/ "Electronics Design" from Airborn] gives an overview of the complete process: specification, (schematic) circuit design, layout, prototypes, firmware, pilot run, production. | * [http://airborn.com.au/method/ "Electronics Design" from Airborn] gives an overview of the complete process: specification, (schematic) circuit design, layout, prototypes, firmware, pilot run, production. | ||
* EDA electronic design automation software is a subset of CAD in general. Is there a wiki that discusses CAD in general? Until I find it, I'm going to post these tools here: "Google SketchUp is a powerful yet easy-to-learn 3D software tool" http://sketchup.google.com/ ; "Inkscape is the best tool for SVG standard vector graphics" http://wiki.inkscape.org/ ; Visual Wiki http://visualwiki.org/ | * EDA electronic design automation software is a subset of CAD in general. Is there a wiki that discusses CAD in general? Until I find it, I'm going to post these tools here: "Google SketchUp is a powerful yet easy-to-learn 3D software tool" http://sketchup.google.com/ ; "Inkscape is the best tool for SVG standard vector graphics" http://wiki.inkscape.org/ ; Visual Wiki http://visualwiki.org/ | ||
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* [http://www.electricstuff.co.uk/pcbs.html electricstuff.co.uk/pcbs] | * [http://www.electricstuff.co.uk/pcbs.html electricstuff.co.uk/pcbs] | ||
* [http://www.fullnet.com/~tomg/gooteepc.htm fullnet.com/~tomg/gooteepc] | * [http://www.fullnet.com/~tomg/gooteepc.htm fullnet.com/~tomg/gooteepc] | ||
− | * Dave McGuire says "The notion that through-hole soldering is easier than soldering surface-mount devices is, and always has been, [http://archives.seul.org/geda/user/Aug-2004/msg00175.html a myth.]" | + | * Dave McGuire says "The notion that through-hole soldering is easier than soldering surface-mount devices is, and always has been, [http://archives.seul.org/geda/user/Aug-2004/msg00175.html a myth.]" |
* [http://www.instructables.com/id/Intro-into-SMD-Soldering/ Intro into SMD Soldering] | * [http://www.instructables.com/id/Intro-into-SMD-Soldering/ Intro into SMD Soldering] | ||
* [http://PMinMO.com/ PMinMO.com is THE PLACE for DIY CNC driver information] | * [http://PMinMO.com/ PMinMO.com is THE PLACE for DIY CNC driver information] | ||
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== Environmental Issues == | == Environmental Issues == | ||
− | + | ||
+ | see [[better for the environment]]. | ||
+ | |||
[[Category:Techniques]] | [[Category:Techniques]] |