most recent 30 from http://chiphacker.com 2010-03-16T17:10:58Z http://chiphacker.com/feeds http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://chiphacker.com/questions/1911/microprogramming-vs-machine-language-programming Louis 2010-03-16T01:51:31Z 2010-03-16T15:48:39Z

<p>I'm a bit confused between the microprogramming level vs machine language level. For example:</p> <ol> <li>Where do both types of programs reside while being executed?</li> <li>Do either have a 1:1 mapping to assembly language true-op instructions?</li> <li>Is the format of either defined by the processor architecture?</li> </ol>

http://chiphacker.com/questions/1847/does-this-exist-insulating-material-to-cover-circuit stuckie27 2010-03-13T12:27:32Z 2010-03-16T15:30:32Z

<p>For example when you build a circuit you have the board and the components between them is air.</p> <p>Is there a clay like material that will act like air does?</p> <p>Application: you could bundle simple circuits into a ball, attach adhesive to the outside and throw them at things (LED throwie)</p>

http://chiphacker.com/questions/1886/in-theory-is-it-possible-to-make-a-logic-gate-that-uses-zero-current endolith 2010-03-15T16:45:52Z 2010-03-16T15:20:37Z

<p>CMOS greatly reduces the current draw of ICs because one of the complementary FETs is always in the non-conducting mode, so there is only a flow of current during the transition between states, which is just the amount of charge on the gate's equivalent capacitance and maybe some leakage when both gates are open momentarily. </p> <p>Is it theoretically possible to make a logic gate that has zero leakage while changing states (using any realistic technology), and the signal is just passed through the circuit as changes in voltage causing other changes in voltage? If not, what's the theoretical minimum?</p>

http://chiphacker.com/questions/1904/are-solder-fumes-bad-for-me Joby Taffey 2010-03-15T22:13:03Z 2010-03-16T01:04:02Z

<p>I do a fair bit of soldering (lead-free). Is breathing in solder/flux/paste fumes actually going to harm me?</p> <p>Are cheap fume extractors worth buying?</p>

http://chiphacker.com/questions/1869/theory-with-an-ac-circuit-adding-capicators-will-cause-the-current-trend-twoards stuckie27 2010-03-14T19:36:57Z 2010-03-16T00:49:10Z

<p>so if you add enough caps can you emulate what an inductor is doing, ie. Lead the current so far that it appears to be lagging? </p> <p>I assume this doesn't work, why not?</p>

http://chiphacker.com/questions/1893/cheap-pcb-manufacture Jim 2010-03-15T18:57:27Z 2010-03-15T21:33:26Z

<p>I've been milling over the different options for sourcing professionally manufactured PCBs. I've just started a business and I'm looking to make a few electronic kits, for now were looking at around 100 units at a time - until we secure more finance. Currently we are making simple 1 sided through hole but the next few boards will be SMD double sided, two things are a must tho - a variety of different colour solder masks and custom images in the copper etch not just the silk screen. </p> <p>The thing I was struggling with, in choosing a supplier, is the fact that I'd have to order it from the far east or china to get it at a good price, i'm in the UK and manufacturers are not so cheap for a small run, plus a lot of them out source to china and the far east anyway. I don't have a problem with who manufactures it - as long at the quality is good and the company is not a total moral write-off (with regard to workers' rights). My main issue has been the fact that the PCBs will cost a lot in fuel, air miles or shipping from so far (not to mention clogging all the roads with dangerous lorries).</p> <p>I've started to come to the realization that commercial globalization might have crushed all hope of making the sensible option viable, or am I wrong? </p> <p>Any thoughts on where to get my supplies for electronics and PCBs in particular would be greatly appreciated. Bear in mind I'm located in England, the UK.</p> <p>If my fears are true &amp; it's my only option - can anyone recommend a foreign manufacturer that will do a good deal? </p> <p>Thanks Chiphakers. </p>

http://chiphacker.com/questions/1885/wireless-temperature-sensor jldupont 2010-03-15T13:56:16Z 2010-03-15T20:48:36Z

<p>Are there any low-cost (&lt;50$USD) wireless ambient temperature sensors available?</p> <p>I would like a simple to interface to the sensor i.e. IP over Wifi if at all possible.</p>

http://chiphacker.com/questions/1887/stepper-motors-on-mbed-not-arduino JP 2010-03-15T17:29:47Z 2010-03-15T19:54:00Z

<p>There is some information on chiphacker about using an arduino to control stepper motors (I'm driving Bipolar, 4 wire, motors), however I'm finding it hard to know how to control a stepper motor using my <a href="http://mbed.org" rel="nofollow">mbed device</a>.</p> <p>The fact that I'm using an mbed is really by-the-by, I've rigged up an H-Bridge so that I have 4 pinouts of my microcontroller/microprocessor going to the required pins of the H-Bridge (like this: http:/[I'm new here, can't post URLs]/www.tigoe.net/pcomp/img/stepper-bipolar-hbridge.jpg) What pulses should I send to which of the pins when? I can PwmOut if thats more useful.</p> <p>Any advice would be very welcome, even if its just a URL to a reasonably detailed tutorial. Thanks!</p>

http://chiphacker.com/questions/1888/mbed-as-a-programmer JP 2010-03-15T17:38:26Z 2010-03-15T19:48:57Z

<p><em>For those of you that haven't heard of the <a href="http://mbed.org" rel="nofollow">mbed</a> I'd highly recommend having a look at it for rapid prototyping!</em></p> <p>So, the mbed is a 100MHz microprocessor that appears as a usb mass storage device when you plug it into a computer via USB. You can program it by using an online IDE which spits out compiled binary files you can drag-drop into the drive (on any OS) making it a very versatile and very easy to use tool for beginners (like myself!)</p> <p>As with all of these programmable ICs they have a limited number of IO pins, so if you wanted to drive 150 LEDs individually you'd need to have some kind of intermediatry control device. I'm considering using ATtiny devices to do just that:</p> <ol> <li>Is using ATtiny devices a good way to achieve control over a large number of LEDs? (considering my lack of experience with hardware)</li> <li>Would it be hard to port the code from the arduino ISP so that I could use my mbed as a programmer for programming ATtiny?</li> <li>Am I better off using PIC chips?</li> </ol> <p>Many thanks!</p>

http://chiphacker.com/questions/1842/waterproof-temperature-probe smoore 2010-03-12T18:02:04Z 2010-03-15T12:39:47Z

<p>I'm looking into building a temperature monitoring system, and I want the sensor to have the ability to be submersed into boiling water. Can a thermocouple handle this? I'm looking into <a href="http://www.sparkfun.com/commerce/product_info.php?products_id=251" rel="nofollow">this</a> one now, but I'm not sure if it's waterproof.</p> <p>My other idea would be to drop a <a href="http://www.sparkfun.com/commerce/product_info.php?products_id=8227" rel="nofollow">small temperature sensor</a> into an aluminum tube and seal it off.</p> <p>Any ideas or suggestions?</p> <p><strong>EDIT:</strong> Sorry, I should have provided more context with my question. To clarify some things, the sensor will be used to monitor and control water temperatures ranging from 30F to 230F, not just to test when water is boiling :). Also, the water being monitored is consumable, so the sensor needs to be food safe as well, and since this is a hobby project, I'm trying to keep the sensor as cheap as possible.</p>

http://chiphacker.com/questions/1781/usb-scope-probe-request-for-comments-and-ideas Adam Davis 2010-03-08T15:23:18Z 2010-03-15T08:14:34Z

<p>Idea:</p> <p>Take one oscilloscope probe, and one USB cable. Cut the BNC connector off the oscilloscope probe, and the USB B connector off the USB jack and splice them together.</p> <p>Mount all the USB &lt;--> analog circuitry inside the scope probe body and/or the USB A connector body. It would essentially compete with all the other USB oscilloscopes out there, but it would be in a single cable design - no extra boxes, etc.</p> <ol> <li>Is this a product you would like?</li> <li>What are your minimum specifications for this type of product?</li> <li>What are your ideal specifications for this type of product?</li> <li>Would this be any more useful or desirable than the current USB oscilloscopes available?</li> </ol> <p>My biggest concerns are:</p> <ul> <li>Obtaining the speed necessary to be reasonably useful without requiring a lot of components</li> <li>Synchronizing multiple probes into the computer (Getting nS accuracy without wiring the probes together seems problematic...)</li> <li>Fitting it all into the form factor and power limitations of a USB port (ideally 100mA unpowered hub ~0.5W)</li> <li>Keeping the assembled cost low</li> </ul> <p>I'd appreciate feedback on any or all of the above (what you want vs how to implement it). Ideally it'd be completely open source, but using very tiny surface mount parts it might not be easily assembled by hand.</p>

http://chiphacker.com/questions/1870/where-can-i-fnd-a-header-for-this-goofy-chip stuckie27 2010-03-14T20:38:49Z 2010-03-15T06:00:12Z

<p>I got this chip and didn't realize the pins were not the normal spacing.</p> <p><img src="http://www.themountainfold.com/test/03142010046.jpg"></p> <p>Anybody know where to find a header for it.</p> <p>BTW the chip is a re-issue of the old sound chip SN76477</p> <p><img src="http://www.themountainfold.com/test/IMG_1119.png"></p>

http://chiphacker.com/questions/984/best-serial-monitor Hristos 2009-12-10T22:32:15Z 2010-03-15T01:09:03Z

<p>I just recently started using a Sparkfun serial lcd. I am able to control it through an arduino, but I want to be able to control it through a terminal on my computer. To be able to move the cursor or clear the screen, you need to be able to send hexadecimal code to it, for example, 0xFE. I am unable to find an open source terminal program for windows that will give me this functionality. An example of a program that works very well is Eltima serial port monitor, although it is rather expensive for just a student. I have a usb to serial FTDI breakout board to get the signal to the lcd. Any suggestions as for programs, under Windows 7, will be greatly appreciated.</p>

http://chiphacker.com/questions/1830/md5-implementation-for-microcontroller sheepsimulator 2010-03-11T16:55:33Z 2010-03-15T00:43:21Z

<p>Does anyone have any examples of the <a href="http://en.wikipedia.org/wiki/MD5" rel="nofollow">MD5 algorithm</a> for a microcontroller (preferably an 8-bit one)? Our project is going to use a Microchip PIC18 series device.</p>

http://chiphacker.com/questions/1873/simulate-hdd-using-atmega168 usecide 2010-03-14T21:12:19Z 2010-03-14T22:38:42Z

<p>I'm going to start a new project and I wonder if the concept makes sense. (I'm not so familiar with ATA specifications to answer this by myself :))</p> <p>The concept:</p> <p><b>HW design:</b></p> <p>"SATA connector on motherboard" &lt;-> "SATA cable" &lt;-> "SATA/IDE HW converter" &lt;-> "ATMEGA168"</p> <ul> <li><p>"SATA connector on motherboard" &lt;-> "SATA cable" - Device would be connected to SATA port on PC motherboard with typical SATA cable</p></li> <li><p>"SATA/IDE HW converter" - on my PCB I will use one of SATA/IDE controllers, so far I've found: JMicron - JM20330,<br> Atmel - AT78C5010,<br> ACARD - ARC-770</p></li> <li><p>"ATMEGA168" - as programmable unit I'd like to use ATmega168 (or any other cheap 8-bit microcontroller)</p></li> </ul> <p><b>Purpose</b></p> <p>With this device I'd like to simulate presence of hard drive in a system. As I want SATA/SCSI stack to be used by OS I need to use SATA ports on motherboard. AFAIK connecting to SATA interface without SATA/IDE converter is impossible with ATMega microcontrollers due to big speed of SATA bus interface. Nevertheless I've found IDE/ATA implementation for 8-bit uC: <a href="http://www.opend.co.za/hardware/avride/avride.htm" rel="nofollow">http://www.opend.co.za/hardware/avride/avride.htm</a></p> <p><b>Wonders</b></p> <p>My biggest concern is the SATA/IDE converter, I wonder if it can be easly used with micro-controllers as ATMega?</p>

http://chiphacker.com/questions/1872/is-there-a-more-economical-version-of-this-powersource-prototyper-the-cadet stuckie27 2010-03-14T20:53:41Z 2010-03-14T20:53:41Z

<p>This is what I want....problem is that they are expensive, really expensive ($500). Is there a more economical version?</p> <p><a href="http://tequipment.net/ELCADET2.html" rel="nofollow">http://tequipment.net/ELCADET2.html</a></p> <p><img src="http://tequipment.net/ProductImages/E&amp;L/CADET2_mid.jpg"> Features:</p> <pre><code>* Expanded Removeable breadboard area * Two open collector pulsers * Built-in multi-waveform function generator * Quad voltage power supply: Three DC &amp; one low voltage AC * Functions with optional electronics trainer boards * Built-in logic probe with pulse capture * BCD to 7 segment decoder/display * 8 channel logic indicatorsSpecifications </code></pre> <p>The C.A.D.E.T. II is a Complete Electronics Trainer that includes all the functions needed to teach basic AC/DC, Linear and Digital Electronics courses. The unit contains all the functions of our highly acclaimed original C.A.D.E.T. plus frequently requested features from educators worldwide.</p> <p>The breadboard area is 33% larger than original C.A.D.E.T., holds up to 32 IC's and comes standard as a removable socket plate with velcro. If you prefer, it can be ordered withour bread boards for use with the extensive line of E&amp;L Trainer Boards. The built-in logic probe will detect narrow logic pulses and eliminate the need for extra lab equipment. The BCD to 7 segment display/decoder saves students time when constucting circuits. The Quad Voltage Power Supply has +5 VDC, two variable DC outputs, and a fixed 12.6 VAC center tapped output. The trainer also includes 8 TTL compatible logic switches and two pulsers.</p>

http://chiphacker.com/questions/1856/how-to-i-determine-interpret-values-of-autoranging-multimter Greg 2010-03-13T19:39:28Z 2010-03-14T11:17:06Z

<p>I have an autoranging multimeter and many AA batteries.... how do I interpret the readings when deciding to keep or discard AA (1.5 volt) batteries?</p>

http://chiphacker.com/questions/1866/cant-get-ds1077-programmable-oscillator-to-work Malvineous 2010-03-14T08:29:58Z 2010-03-14T08:29:58Z

<p>Hi all,</p> <p>I'm trying to get the <a href="http://datasheets.maxim-ic.com/en/ds/DS1077.pdf" rel="nofollow" title="DS1077 datasheet">DS1077</a> to work, but I can't for the life of me figure out what I'm doing wrong. I'm using the defaults for the MUX and BUS registers, and programming in my own DIV frequency has no effect. I can read out the registers over I2C and they return the values I set, but the oscillator output (as measured on my scope) is nothing like what it should be. I tried copying the values in from <a href="http://www.sparkfun.com/datasheets/BreakoutBoards/DS1077v2.c" rel="nofollow" title="C code">SparkFun's example</a> (I'm using their breakout board) but the "40kHz" output is way above the 60MHz bandwidth of my scope.</p> <p>I found an <a href="http://www.maxim-ic.com/app-notes/index.mvp/id/171" rel="nofollow">example on Maxim's website</a> and they recommend you tie CTRL0 and CTRL1 to GND if you're not using them - but if I tie CTRL1 to GND mine stops responding to I2C messages! I have to tie CTRL1 to VCC to get it to respond over I2C (no mention of that in the datasheet), but that disables the oscillator output. Otherwise my "circuit" is the same as their example - SDA/SCL go to an Arduino, and the OUT pins go to my scope. VCC and GND are connected correctly and within spec.</p> <p>I've got no idea what's going on, it seems really simple but I still can't get it to work :'-( Has anyone encountered anything like this before? Any ideas to help narrow down the problem?</p>

http://chiphacker.com/questions/991/arm-cortex-m3-devolpment-tools mba7 2009-12-11T17:19:49Z 2010-03-13T23:19:23Z

<p>i plannig to migrate to the NXP Cortex M3 architechture, and i'm a little lost between the existant develment tools.</p> <p>Keil is a expensive and i don't know if it worth. Anyone who have tried some compiler can give an advice?</p> <p>i found this compiler <a href="http://www.code-red-tech.com/red-suite-2.php" rel="nofollow">http://www.code-red-tech.com/red-suite-2.php</a> it seems good and not expensive. Anyone who tried it or know about it can give me more info?</p>

http://chiphacker.com/questions/1388/what-are-the-best-electronics-soldering-techniques mad_z 2010-01-06T22:55:40Z 2010-03-13T23:09:23Z

<p>Is there a tutorial that shows different techniques and the dos/don't of soldering?</p> <p>I was doing a kit last night that just said heat up both components for 5 seconds then put the solder close and let it oose into the join -> they all worked nicely....but as instructions go they are a bit basic, and from past experience there are certain components that you shouldn't heat up too much.</p> <ul> <li>I was doing Through-hole soldering but Surface Mount would also be great to learn about.</li> </ul>

http://chiphacker.com/questions/1849/is-there-a-correct-resistance-value-for-pull-up-resistors JonathanD 2010-03-13T13:36:33Z 2010-03-13T22:40:54Z

<p><a href="http://ww1.microchip.com/downloads/en/DeviceDoc/21203P.pdf" rel="nofollow">The datasheet</a> of the 24LC256 EEPROM states that:</p> <blockquote> <p>The SDA bus requires a pull-up resistor to VCC (typical 10 kΩ for 100 kHz, 2 kΩ for 400 kHz and 1 MHz).</p> </blockquote> <p>I thought that any resistor with a kΩ value would do the job (and it seems that my EEPROM works fine at different frequencies with a 10 kΩ resistor).</p> <p>My questions are:</p> <ul> <li>is there a correct value for pull-up resistors ?</li> <li>is there a law/rule to determine this value ?</li> <li>how do different resistance values affect the I²C data bus ?</li> </ul>

http://chiphacker.com/questions/1808/should-i-get-the-pickit-2-or-3 Darren Landrum 2010-03-10T02:36:30Z 2010-03-13T22:12:09Z

<p>Okay, having decided to pitch myself at the PIC family (including dsPIC), I now have a question about programmers. I've been hearing a lot of bad things about the new PICKit 3, and am wondering if I should get that or the apparently more venerable PICKit 2? If I want to be able to use the newest PICs, I think I might need to buy the latest, but I'm not so sure. Thank you!</p>

http://chiphacker.com/questions/1815/arduino-pcb-etchable-pdf Rick_2047 2010-03-10T14:58:47Z 2010-03-13T21:17:18Z

<p>Hi, where I live one cannot buy an arduino very ceap. I figure if I make one for my own purpose on a pcb that would be much cheaper and would be much more fun. Now I cannot find any etch-able pdf on the internet so can anyone point me to some?</p>

http://chiphacker.com/questions/1848/custom-led-manufacturing stuckie27 2010-03-13T12:48:28Z 2010-03-13T15:31:27Z

<p>I would like to fab some custom LEDs.</p> <p>Embed a resistor in the plastic, is there a smart way to go about doing this? </p> <p>I know Alibaba other than that nothing really.</p>

http://chiphacker.com/questions/1829/best-arduino-pocket-reference Diosces 2010-03-11T16:28:35Z 2010-03-12T21:34:48Z

<p>I know there are plenty of references, tutorials and projects posted on line. I'm looking for a decent Arduino reference/project paperback I can read while traveling, etc.</p> <p>Thanks!</p>

http://chiphacker.com/questions/1840/lighting-project-advice fred 2010-03-12T00:27:30Z 2010-03-12T03:45:29Z

<p>I am developing a school project to make a rechargeable outdoor light for use at BBQ's etc.</p> <p>The idea being, on the wall is a mains powered charging dock, with 4 battery powered lights attached.</p> <p>Once one of the light is removed from the dock, it lights, giving 2-3 hours of light.</p> <p>Returned to the dock to charge again.</p> <p>I have the product design part sorted , just need some help with electronics. Would any of you guru's be able to help me out?</p> <p>I guess the lights would be a series of super bright LED's, running off NiMH rechargeable battery pack in each, these charging through a 'connector' to the charging dock. The simpler the better.</p> <p>To switch them on automatically , once removed from charging dock ? I am not sure.</p> <p>Your time and help would be greatly appreciated,</p> <p>Thanks for your time</p>

http://chiphacker.com/questions/1827/pic18f97j60-ethernet-performance mjh2007 2010-03-11T15:03:29Z 2010-03-11T23:48:33Z

<p>Does anyone else use the PIC18F97J60 Ethernet capability? If so what kind of RX/TX performance is typical for that chip? I was running the TCPPerformanceRX/TX applications provided as part of the Microchip TCP/IP stack and getting between 1500-2000 bytes/sec TX and 60-80 bytes/sec RX. Receive seems way slower than it should be.</p>

http://chiphacker.com/questions/1792/reading-rtd-temperature-sensor mjh2007 2010-03-08T21:11:29Z 2010-03-11T21:25:33Z

<p>I've had a number of issues getting good stable analog readings from an RTD temperature sensor. Typically the sensor/circuit/software works fine at my desk then when it is installed on our industrial equipment the temperature readings have a tendency to bounce as much as +/- 5 Deg C. The circuit is very basic, a voltage divider is formed between a fixed resistor and an RTD connected to ground. The voltage at the RTD is then fed into a programmable gain amplifier set at 16 V/V. The analog signal output from the programmable gain amplifier is then fed into a 10-bit ADC on a PIC microprocessor. I've implemented a low pass filter in software to attempt to fix the problem, but the temperature readings are still very unstable. Does anyone have any suggestions about where I could look to find the source of the problem and correct it?</p>

http://chiphacker.com/questions/1834/qtr-8rc-white-line-detection Hamza Yerlikaya 2010-03-11T20:24:54Z 2010-03-11T20:24:54Z

<p>I am using a qtr8-rc sensor array on a line following robot, When I use it on a black line on a white surface it works but when i try to use it on a black surface with white line i can't get correct results, i have extracted the following code from my robot to test it separately but no matter what i do i can not get it to detect white line on a black surface...</p> <p><pre><code></p> <h1>include "PololuQTRSensors.h"</h1> <p>PololuQTRSensorsRC qtr;</p> <p>void setup(){ Serial.begin(9600); qtr.init((unsigned char[]) {2,3,4,5,6,7,9}, 7);</p> <p>int i; for (i = 0; i &lt; 250; i++){ // make the calibration take about 5 seconds qtr.calibrate(QTR_EMITTERS_ON); delay(20); } }</p> <p>void loop(){</p> <p>unsigned int val[7]; qtr.readCalibrated(val); int line = qtr.readLine(val,QTR_EMITTERS_ON,true);</p> <p>Serial.print(line); Serial.print(" R&lt; "); Serial.print(val[0]); Serial.print(" "); Serial.print(val[1]); Serial.print(" "); Serial.print(val[2]); Serial.print(" "); Serial.print(val[3]); Serial.print(" "); Serial.print(val[4]); Serial.print(" "); Serial.print(val[5]); Serial.print(" "); Serial.print(val[6]); Serial.print(" "); Serial.print(val[7]); Serial.print(" "); Serial.println(" >L ");</p> <p>} </pre></code></p> <p>Some sample reading I am getting,</p> <p><pre><code> 3200 R&lt; 553 473 397 113 120 533 304 104 >L 3432 R&lt; 567 514 474 113 120 393 82 104 >L 3494 R&lt; 572 625 544 94 100 487 69 104 >L 3418 R&lt; 543 421 506 88 93 305 64 104 >L 3407 R&lt; 529 403 487 69 73 290 50 104 >L 3403 R&lt; 524 397 480 62 67 284 46 104 >L 3506 R&lt; 538 561 474 37 40 264 27 104 >L 3503 R&lt; 538 543 455 18 20 248 13 104 >L 3519 R&lt; 558 567 474 44 46 269 32 104 >L 3537 R&lt; 577 590 500 69 73 290 50 104 >L 3545 R&lt; 577 614 532 94 100 310 69 104 >L 3466 R&lt; 611 497 397 94 100 310 69 104 >L 3534 R&lt; 572 584 500 62 67 284 46 104 >L 3534 R&lt; 572 584 500 62 67 284 46 104 >L</p> <p></pre></code></p> <p>All numbers are way too close so readLine does not return a correct position. One of the pins on my arduino does not work so I skipped connecting one of the sensors(sensor 7)</p>

http://chiphacker.com/questions/592/op-amp-tutorial-for-electronic-noobs Nikolaus Gradwohl 2009-11-21T20:01:19Z 2010-03-11T15:32:10Z

<p>Hi, </p> <p>can anyone point me to a tutorial for electronic noobs that explains how to use op-amps and what i can do with them, besides amplification?</p>