http://www.opencircuits.com/api.php?action=feedcontributions&user=68.243.160.241&feedformat=atomOpenCircuits - User contributions [en]2024-03-28T15:10:07ZUser contributionsMediaWiki 1.34.2http://www.opencircuits.com/index.php?title=Hardware_tool&diff=11131Hardware tool2007-11-17T17:59:53Z<p>68.243.160.241: /* Storeage compartments */</p>
<hr />
<div>Getting started with electronics design takes buying some equiptment, but it can be confusing what to buy. I'm going to list here some of the items that I throught were helpful getting started.<br />
<br />
== Breadboard with power supply ==<br />
<br />
Most people start with electronics by connecting up circuits on a breadboard. A breadboard is great for trying out circuits before moving to more permanent construction techniques such as perfboard or custom PCBs.<br />
<br />
<br />
== Spools of wire ==<br />
<br />
Wire is available as stranded or solid. Solid works best with boardboards and perfboards. Stranded works best when creating cables for interboard connections.<br />
<br />
<br />
== Multimeter ==<br />
<br />
Radio Shack is a good source of cheap multimeters. <br />
<br />
== Oscilloscope ==<br />
<br />
An oscilloscope is critical for debugging analog circuits or communication protocols. I prefer PC based oscilloscopes since they are cheaper then dedicated equiptment and are more automated then a traditional phosphor oscilloscope. Parallax makes a very cheap low end PC based oscilloscope that is great for getting started.<br />
<br />
[http://www.parallax.com/detail.asp?product_id=28014]<br />
<br />
== Storage compartments ==<br />
<br />
As more components are bought, it becomes necessary to store all the components in an organized way and storage compartments are very helpful. These can be bought at the local home improvement or hardware store.<br />
<br />
== Resistor kit ==<br />
<br />
It's important to have alot of different resistor values around as it's almost impossible to buy the correct values in advance. Digikey sells resistors in kits that have a small number of all the standard resistor values.<br />
<br />
== Capacitor kit ==<br />
<br />
Capacitors are like resistors. You need a large number of values. Digikey also sells capacitor kits in addition to the resistor kits.<br />
<br />
<br />
== Microcontroller Programer/ICD ==<br />
<br />
Microcontrollers are a great way to get started in digital electronics. They are essentially a little computer on a single chip. Unlike large computers these processors usually don't run a full blown operating system so dedicated hardware is used for programming an debugging. In Circuit Debugging are the prefered way to go for development since it's a huge time saver to be able to program and debug software without needing to pull the chip from the circuit. Beleve me, spend the extra money it is worth it.<br />
<br />
== Development Boards ==<br />
<br />
If you are willing to spend some money development boards are a quick way to get started. They typically have a microcontroller, voltage regulator, some LEDs, and some sensors all on one board. The downside is that if you break anything on the board you have to buy a whole new board. With descrete components only the broken part needs to be replaced. On the other hand, more and more components are only available in surface mount packages which almost require a custom PCB to use at all. ARM processors are relatively powerfull microcontroller but at present are not available in through hole versions.</div>68.243.160.241http://www.opencircuits.com/index.php?title=ARMUS_Embedded_Linux_Board/&diff=11129ARMUS Embedded Linux Board/2007-11-17T17:56:49Z<p>68.243.160.241: Replacing page with '.'</p>
<hr />
<div>.</div>68.243.160.241http://www.opencircuits.com/index.php?title=Photoetching&diff=11128Photoetching2007-11-17T17:55:22Z<p>68.243.160.241: </p>
<hr />
<div>== Negative Film ==<br />
<br />
Printed Circuit Boards<br />
I start with a hand drawn schematic. The schematic is then prototyped on a breadboard (prototype board). Breadboarding provides a test platform for circuit designs. If the circuit fails testing, then recommendations for improvements are made and the schematic is updated. Once a circuit is thoroughly tested and proven reliable then the circuit is entered into a CAD package for electronic storing, editing and printing.<br />
<br />
A CAD software package was used to design the printed circuit board (PCB) layouts. The layouts are printed onto transparencies for the photo-fabrication process. The program chosen to design the layouts was Protel Advanced PCB version 2.8. The layouts are designed manually from the schematics. Protel allows the creation of a custom library of components. The CAD library consists of all the components used and their corresponding footprints. Each component in a schematic has a footprint. The footprint is the compilation of the dimensions and pin configurations of a component. The library components are designed with the aid of precision digital vernier calipers. Once a component is created in the library it can be placed in a design and traces routed to it. <br />
<br />
The PCBs were made using a positive photo-fabrication process. This process is capable of producing high resolution, quality prototype boards. The PCB material used is a presensitized copper clad board. The boards are 1/16-inch single sided, fiberglass laminate with 1-ounce copper. Before exposing the boards I cut them to the desired dimensions.<br />
<br />
Exposing the boards must take place in a darkroom since the boards are photosensitive. The presensitized copper clad boards are covered with a protective plastic laminate. Beneath the protective laminate is the resist coating over the copper. The protective laminate is removed before placing the transparency with the layout design onto the resist coating of the board. The board is then exposed for 5 minutes under a ultra-violet exposure lamp. <br />
<br />
After being exposed the board is developed using the developing solution. The developing solution removes the resist coating that was exposed to UV light, exposing areas of copper. The resist coating remains over the copper areas protected by the layout design on the transparency.<br />
<br />
The exposed copper is etched in a bubble-etching tank using Ammonium Persulfate solution. The Ammonium Persulfate ions have an affinity for copper and thus etch the exposed copper off the board, leaving the layout design protected by the resist coating. <br />
<br />
The components used for the design are thru-hole and thus require holes to be drilled in the PCB for placement. The holes are drilled using carbide bits. Carbide bits are required to drill through the fiberglass laminate. Regular bits are not durable enough and wear out too quickly.<br />
<br />
<br />
Populating the boards consists of placing the components corresponding to the bill of materials and the component silkscreen. The bill of materials provides the components part numbers and details. The silkscreen printout from the layout design provides the component location on the board. <br />
<br />
The components are soldered on starting with jumper wires, resistors and working up to ICs and larger components.<br />
<br />
== External Links ==<br />
* [http://diypcb.googlepages.com Yet another PCB guide]<br />
<br />
[[Category:Techniques]]</div>68.243.160.241http://www.opencircuits.com/index.php?title=Photoetching&diff=11127Photoetching2007-11-17T17:54:06Z<p>68.243.160.241: </p>
<hr />
<div>[http://samsung-930b.straip.cn/ samsung 930b] {{stub}}<br />
<br />
== Negative Film ==<br />
<br />
Printed Circuit Boards<br />
I start with a hand drawn schematic. The schematic is then prototyped on a breadboard (prototype board). Breadboarding provides a test platform for circuit designs. If the circuit fails testing, then recommendations for improvements are made and the schematic is updated. Once a circuit is thoroughly tested and proven reliable then the circuit is entered into a CAD package for electronic storing, editing and printing.<br />
<br />
A CAD software package was used to design the printed circuit board (PCB) layouts. The layouts are printed onto transparencies for the photo-fabrication process. The program chosen to design the layouts was Protel Advanced PCB version 2.8. The layouts are designed manually from the schematics. Protel allows the creation of a custom library of components. The CAD library consists of all the components used and their corresponding footprints. Each component in a schematic has a footprint. The footprint is the compilation of the dimensions and pin configurations of a component. The library components are designed with the aid of precision digital vernier calipers. Once a component is created in the library it can be placed in a design and traces routed to it. <br />
<br />
The PCBs were made using a positive photo-fabrication process. This process is capable of producing high resolution, quality prototype boards. The PCB material used is a presensitized copper clad board. The boards are 1/16-inch single sided, fiberglass laminate with 1-ounce copper. Before exposing the boards I cut them to the desired dimentions.<br />
<br />
Exposing the boards must take place in a darkroom since the boards are photosensitive. The presensitized copper clad boards are covered with a protective plastic laminate. Beneath the protective laminate is the resist coating over the copper. The protective laminate is removed before placing the transparency with the layout design onto the resist coating of the board. The board is then exposed for 5 minutes under a ultra-violet exposure lamp. <br />
<br />
After being exposed the board is developed using the developing solution. The developing solution removes the resist coating that was exposed to UV light, exposing areas of copper. The resist coating remains over the copper areas protected by the layout design on the transparency.<br />
<br />
The exposed copper is etched in a bubble-etching tank using Ammonium Persulfate solution. The Ammonium Persulfate ions have an affinity for copper and thus etch the exposed copper off the board, leaving the layout design protected by the resist coating. <br />
<br />
The components used for the design are thru-hole and thus require holes to be drilled in the PCB for placement. The holes are drilled using carbide bits. Carbide bits are required to drill through the fiberglass laminate. Regular bits are not durable enough and wear out too quickly.<br />
<br />
<br />
Populating the boards consists of placing the components corresponding to the bill of materials and the component silkscreen. The bill of materials provides the components part numbers and details. The silkscreen printout from the layout design provides the component location on the board. <br />
<br />
The components are soldered on starting with jumper wires, resistors and working up to ICs and larger components.<br />
<br />
== External Links ==<br />
* [http://diypcb.googlepages.com Yet another PCB guide]<br />
<br />
[[Category:Techniques]]</div>68.243.160.241http://www.opencircuits.com/index.php?title=SFE_Footprint_Library&diff=11126SFE Footprint Library2007-11-17T17:50:11Z<p>68.243.160.241: </p>
<hr />
<div><br />
This is the holy grail for [http://www.sparkfun.com Spark Fun Electronics]. Each footprint is a custom layout. This library has been compiled over 5 years and 100s of man hours worth of work. If you are a student, please, enjoy and learn. If you are a professional, please buy something from www.sparkfun.com to help us out.<br />
<br />
<b>Download it now: </b>[[Media:SFE-Custom-Footprints.zip|SFE-Custom-Footprints]]<br />
<br />
Currently we use Protel DXP for 90% of our layouts. Eagle is also used but we don't create as many FPs. The zip file above contains only a Protel library. It does not contain even a minimal one for Eagle. (Is anyone aware of any format conversion utilities which might be helpful? --dave)(''Some format conversion utilities are listed [http://techref.massmind.org/techref/app/format_conversion.htm at the massmind] -- do you know any others? -- David'')<br />
<br />
Please take all these footprints with a grain of salt. Most of the FPs we make are rather exotic and complex. We rarely trust an FP from anyone else thus usually creating our own.<br />
<br />
List of current footprints:<br />
*5-Lead DD PAK - Voltage regulator<br />
*0603 - This is the basic 0603 footprint. Use this or 0603 - OLD1<br />
*0603 - LED<br />
*0603 - OLD1 - Original, tight 0603 layout. Works great, very minimal<br />
*1206 - LED - This is a very revised, nice layout for 1206 LEDs including an expanded paste layer for a nice solid solder connection<br />
*3216 EIA-A - Perfect for 10uF tantulum caps<br />
*7343 EIA-D - Perfect for 100uF tantulum caps<br />
*Antenna - 2.4GHz - This is the antenna found on the RF-24G devices. No guarantees it will impedance match<br />
*Antenna - 2.45GHz - Chip antenna fp<br />
*Antenna - SMA - Vertical mount SMA or RP-SMA connector<br />
*Antenna - SMA - End Launch<br />
*BGA-32 - 32 ball bga for the Analog Device's ADXRS MEMs gyros<br />
*BlueRadio with Antenna - This is the FP for the Bluetooth module. No guarantees. It's a bit odd with restricted areas.<br />
*CF Socket - Basic CF breakout. Start from here and make it fit your part<br />
*CF Socket - Recommended - more silkscreen, wider solder pads<br />
*CNZ1120 - Optical photo intr/sensor fp<br />
*Coin Cell Holder 12mm - SMD<br />
*Coin Cell Holder 20mm - PTH<br />
*Connector Molex x - Vertical and right angle connectors with polarized connectors<br />
*DB9 Headers - various DB9 connector FPs include PTH and end launch<br />
*DIN-3 - DIN connector<br />
*DIP connectors<br />
*GM862 - Cellular module FP with antenna, pin1 indicator, and shield holes (proven, works great!)<br />
*Headers - Various SIP 0.1" headers<br />
*Lassen iQ - Couple FPs for the Lassen iQ with and w/o silkscreen lines (proven, works great)<br />
*LCC8 - Special - Minimal FP for the ADXL series accelerometers from Analog Devices (proven, works great)<br />
*LCD 16x2 - This is mechanical and electrical FP for 16x2 LCD from SFE. (proven, works great)<br />
*LED Polarized - Simple T1, 5mm LED FP<br />
*LED Polarized 3mm - 3mm LED fp, works ok. Hard to see silkscreen<br />
*LFCSP - Recommended and modified FP for the newer ADXL32x series from Analog Devices. Recommended FP is proven and works great.<br />
*microSD Socket - Proven, works great<br />
*MLP-24 - Used for the nRF2401-ish ICs from Nordic. Proven, works great<br />
*MLP-28 - Used for the CP210x USB ICs from SI Labs. Proven, works great<br />
*PG31 - GPS receiver from Laipac. Includes silk area for MMCX connector.<br />
*PIC ICSP Mini - This is a custom FP by SFE. It's a in circuit serial programming jack that is 1.5mm pitch. Used to program just a bootloader onto a board without using up the space of a full sized programming header<br />
*Power Jack - common barrel jacks with silk and mechanical layers<br />
*Power Switch - Common SPDT switch, can be used for power or signal<br />
*QFN-16 - Used for the MMA7260Q triple axis accelerometer. Works great but has some interesting keepout lines to keep vias out from under the IC<br />
*QRD1114 - FP for the QRD1114 IR line sensor<br />
*QUAD44 - TQFP package for the 16F877A IC<br />
*Radial Caps - Various FPs for radial caps. Be sure your part matches the various dimensions.<br />
*RJ11 - Jack for ICD or telephone<br />
*Screw Terminal - 0.1" pitch screw terminal, two position version has two peg holes for structural stability<br />
*SD-MMC Socket - Just what it sounds like<br />
*SJ-2503A - 2.5mm stero jack<br />
*SMA - Diode - Good 1A reverse polarized diode<br />
*SMD Cap - SMD eletrolytics. Use at your own risk<br />
*SOD-323 - Very small diode, good for signals<br />
*SOIC - various soic FPs<br />
*Solder Jumper - NC - Normally closed solder jumper. The paste layer is expanded so during reflow, extra paste is available so the jumper is shorted<br />
*Solder Jumper - NO - Normall Open solder jumper. Paste layer is there, but not enough for a short<br />
*Solder Switch - handy for SMD switches just using a soldering iron<br />
*SOT-23 - Commom BJT footprint with various configuration. Check the datasheet for your particular part.<br />
*SOT-23A - FP for popular small voltage regulators<br />
*SOT-223 - Bigger 1A voltage regulators use this footprint like the [[LM1117]]<br />
*SOT-457 - Transistor array FP<br />
*SPDT Relay - Couple relay footprints<br />
*SSOP - Various SSOP footprints<br />
*Stencil Peg - This is an alignment hole for the Stencil-Alignment-System as well as a stand-off hole.<br />
*Switch - Various momentary switch FPs. SMD, PTH, and Right Angle PTH<br />
*Terminal Block - Various screw terminal blocks<br />
*TO-92 - Various v-reg and PTH transistor FPs<br />
*TO-220 - Various PTH FPs including LM317, LM7805, and heat sinked FPs<br />
*TRF-24G - Popular FPs for the RF-24G 2.4GHz module<br />
*Trim Pot - Couple trimpot FPs<br />
*USB - Various USB connector FPs<br />
*WEEE Icon - The european initiative to limit electronics trash. It's an silkscreen icon that looks like a trash can...<br />
*Xtal-2 - Standard crystal FP<br />
*Xtal-6 - SMD Watch crystal FP<br />
*Xtal-SMD8 - SMD ceramic resonator FP<br />
*Xtal-SMD9 - SMD quartz crystal FP<br />
--[[User:Sparkfun|Sparkfun]] 13:10, 28 January 2006 (PST)</div>68.243.160.241http://www.opencircuits.com/index.php?title=Samtec&diff=11125Samtec2007-11-17T17:49:03Z<p>68.243.160.241: </p>
<hr />
<div><br />
[[Image:Samtec-logo.gif|Samtec]]<br />
<br />
<br />
<b>Description:</b><br><br />
Samtec is a large connector manufacturer that builds parts to order.<br />
<br />
<br />
<b>Sparkfun's opinion and advice:</b><br><br />
As a company, Samtec is reasonably easy to deal with but their website is pretty convoluted. You can try using their build-a-part wizard, but we recommend you get a paper catalog and thumb through. All their literature is beautiful, too bad their website is so difficult to use.<br />
<br />
We buy all sorts of sockets and connectors from them. <br />
<br />
On an interesting note, they have no stock. They build everything to order! We ordered some parts with an incorrect/old part #. Upon receiving 100 bad connectors, we attempted to return them. The customer service rep just stuttered on the phone - they don't do returns! Since they build everything to order, they would have no place to even put returned parts. We were SOL. Kind of a cool business model/concept, but just be sure you've got the right part #. <br />
<br />
To help you get the right part # - they'll send you all sorts of free samples! Way to go Samtec!<br />
<br />
<b>Manufacturer Info:</b><br><br />
[http://www.samtec.com www.samtec.com]<br />
<br />
<b>Contact Info:</b><br><br />
1-800-SAMTEC-9 (who still does this? I hate it when companies list some horrible spelled phone number so here's the real number)<br><br />
1-800-726-8329<br />
<br />
[[Category:Suppliers]]<br />
[[Category:Connectors]]<br />
[[Category:Manufacturers]]</div>68.243.160.241http://www.opencircuits.com/index.php?title=Samtec&diff=11124Samtec2007-11-17T17:48:08Z<p>68.243.160.241: remove spam</p>
<hr />
<div>[http://mesotheliomalaywer.com/yg/CSS/data/touch/bdqtue.html two factor model] {| align=right<br />
|-<br />
| <br />
[[Image:Samtec-logo.gif|Samtec]]<br />
|}<br />
<br />
<b>Description:</b><br><br />
Samtec is a large connector manufacturer that builds parts to order.<br />
<br />
<br />
<b>Sparkfun's opinion and advice:</b><br><br />
As a company, Samtec is reasonably easy to deal with but their website is pretty convoluted. You can try using their build-a-part wizard, but we recommend you get a paper catalog and thumb through. All their literature is beautiful, too bad their website is so difficult to use.<br />
<br />
We buy all sorts of sockets and connectors from them. <br />
<br />
On an interesting note, they have no stock. They build everything to order! We ordered some parts with an incorrect/old part #. Upon receiving 100 bad connectors, we attempted to return them. The customer service rep just stuttered on the phone - they don't do returns! Since they build everything to order, they would have no place to even put returned parts. We were SOL. Kind of a cool business model/concept, but just be sure you've got the right part #. <br />
<br />
To help you get the right part # - they'll send you all sorts of free samples! Way to go Samtec!<br />
<br />
<b>Manufacturer Info:</b><br><br />
[http://www.samtec.com www.samtec.com]<br />
<br />
<b>Contact Info:</b><br><br />
1-800-SAMTEC-9 (who still does this? I hate it when companies list some horrible spelled phone number so here's the real number)<br><br />
1-800-726-8329<br />
<br />
[[Category:Suppliers]]<br />
[[Category:Connectors]]<br />
[[Category:Manufacturers]]</div>68.243.160.241http://www.opencircuits.com/index.php?title=Chalk_Roach&diff=11123Chalk Roach2007-11-17T17:46:51Z<p>68.243.160.241: remove spam</p>
<hr />
<div>This project was developed by the Computing Culture Group at the MIT Media Lab.<br />
<br />
It's now called #6!<br />
<br />
It's a 2"x2" (5cm x 5cm) one-side printed circuit board that supports the very<br />
robust Atmega32 microcontroller.<br />
<br />
Because it's one-sided, you can make them at home with [http://www.techniks.com/how_to.htm Press and Peel Blue] a clothes iron, and Ferric Chloride from Radio Shack. <br />
<br />
It can be configured minimally with just a tiny handful of components yet connect to<br />
so many different things.<br />
<br />
[http://edgy.media.mit.edu:8080/6 Main development page]<br />
<br />
[[Category:Projects]]</div>68.243.160.241http://www.opencircuits.com/index.php?title=Motor_driver&diff=11118Motor driver2007-11-17T17:37:51Z<p>68.243.160.241: remove spam and update some spelling</p>
<hr />
<div><br />
<br />
There are many kinds of motor drivers:<br />
* servo motor controller<br />
* stepper motor controller<br />
* DC motor controller ("brushed")<br />
* AC motor controller ("brushless")<br />
* ... (todo: fill in the other kinds) ...<br />
<br />
A DC motor controller that is 'reversible' generally uses an 'H bridge'. This 'H-bridge' uses four output drivers in a configuration that resembles an H where the load is the cross bar in the middle. The lines on either side of the load (the downward strokes in the H) represent a series connection of a pull-up driver and a pull-down driver. This allows each terminal of the load to be connected to either the positive supply rail, or the negative supply rail. This allows a positive, negative or zero voltage difference across the load. This load voltage is then utilized to provide the desired control required of the motor. The various combinations can give a 'forwards' torque on a DC motor, a 'backwards' torque on the same motor, can allow the motor to free-wheel (without any applied torque) or can provide a locking of the motor such that it resists any attempt to rotate it.<br />
<br />
A single phase AC motor is generally driven in the same way as a DC motor, however instead of operating the motor drive as a constant DC voltage (in either the 'forward' or 'reverse' direction) the AC motor is driven by an approximation to a sinewave. This approximation is created using the H bridge and driving it with a PWM input such that both the positive and negative voltage periods are the same. This is normally achieved either using a sawtooth waveform compared against a sine wave reference, or is done using a lookup table in a microcontroller.<br />
<br />
A similar method is used to drive multiphase (3-phase) AC motors, however instead of just using an H bridge, only a half H bridge is used per phase (3 half-bridges). Each phases half bridge is then driven in the same manner as for the single phase motor, with a phase difference between the phases as appropriate.<br />
<br />
Most stepper motor controllers uses 2 independent H bridges (4 half-bridges) for the 2 independent coils of a stepper motor.<br />
Each possible state (one bridge driving current one way, the other way, or free-floating) of both bridges gives 4 "full steps", 4 "half-steps" between the full steps.<br />
The "microstepping" motor controllers use PWM to gradually change in a sine-wave-like manner from adjacent full-steps and half-steps.<br />
<br />
((fill in more details here...))<br />
<br />
== noise control ==<br />
<br />
Many motors make sparks when the brushes make or break contact.<br />
This causes causes lots of electrical noise ("brush noise").<br />
Your TV-watching neighbors won't be happy if you allow this noise to leak out.<br />
<br />
"Sparks emit RF energy from DC to daylight as I was once told by an EMC expert."<br />
--<br />
HydraRaptor: [http://hydraraptor.blogspot.com/2007/09/dc-to-daylight.html "DC to daylight"]. More details: <br />
HydraRaptor: [http://hydraraptor.blogspot.com/2007/10/gm3-motor-suppressor.html "GM3 motor suppressor"]<br />
<br />
<br />
== current sense ==<br />
<br />
Often people want to measure the current going through the motor.<br />
<br />
There are 3(?) basic techniques:<br />
* low-side current shunt<br />
* high-side current shunt<br />
* magnetic field sense<br />
* ... ''(any others I missed?)'' Yes, [http://www.4qdtec.com/mircl.html pseudo 'mirror' current sensing a MOSFET] -- sampling the voltage across a MOSFET while it is turned on. That voltage is linear with current but varies with temperature. If the purpose of measuring current is to turn off the MOSFET before it overheats, the variation with temperature doesn't matter. (''A true [http://en.wikipedia.org/wiki/Current_mirror current mirror] isn't useful for motors, right?'') <br />
* the "non-dissipative overcurrent protection", a kind of current mirror used in the L6208N ...<br />
* ... ''(any others I missed?)''<br />
<br />
Low-side is (electrically) the simplest.<br />
<br />
For smaller motors, the current is usually measured by<br />
running the current through a shunt resistor,<br />
and measuring the voltage across the resistor.<br />
<br />
In situations where low-side sensing is difficult ( automobile electronics bonded to the "GND" car frame; other systems where it is inconvenient to put a resistor on the "lo" power wire), we turn to high-side sensing.<br />
<br />
[http://www.newark.com/jsp/search/browse.jsp;Ntt=high side current sense Newark: high side current sense]; [http://www.digikey.com/scripts/DkSearch/dksus.dll?KeywordSearch</div>68.243.160.241