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I want to pick up an Arduino starter kit, or one of some other micro controller or microprocessor that is easy to learn to program. If possible I'd like one that comes with bluetooth modules, otherwise I will just buy them separately. Are there any hiccups or specific processors I should expect to need if I want to communicate with bluetooth modules or are some modules straight-forward? My biggest question is what type of starter kit should I look for? I would love to see specific recommendations or what you guys have used. Price is not a concern; I know how these are expensive. I'm also curious what type of microcontroller I most want to play around with. Something like ATmega328? I don't think I need the sophistication of an ARM processor but I want to hear any advice. Heran Bago fucked around with this message at 06:25 on Nov 6, 2010 |
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Nov 6, 2010 06:21
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Hillridge posted:I feel like I know what that goes to, but just can't quite place it. The circuit takes 3V, then charges two capacitors up to 50V, the outputs are high voltage pulses. The chip in the middle is basically a timer chip, which does varies the output frequency and width, the chip also uses very high frequencies with either an inductor or transformer to up the voltage to 50V. So I kind of generally know what the circuit does. I wanted mainly tips on the techniques on how to put the circuit into a circuit diagram. The only thing I've found online is to overlap photos of the back and front. I'm surprised there isn't anything else on the net.
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Nov 6, 2010 12:35
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Heran Bago posted:I want to pick up an Arduino starter kit, or one of some other micro controller or microprocessor that is easy to learn to program. If possible I'd like one that comes with bluetooth modules, otherwise I will just buy them separately. Are there any hiccups or specific processors I should expect to need if I want to communicate with bluetooth modules or are some modules straight-forward? In my opinion, the best mix of simple and cheap is to grab yourself a standard Arduino Uno, and pick up a separate Bluetooth module (I grabbed myself a BlueSMiRF Gold). The BlueSMiRF is seriously brain-dead easy to work with: you pretty much just connect the TX/RX to the Arduino's RX/TX, pair with the module using your laptop or another Bluetooth thing, and open up a serial connection over the virtual COM port that it creates. The Sparkfun page I linked you to lists documents that describe the process fully. There's also the Arduino Bluetooth, but that's missing the USB connection that the Uno has. If you're just starting with microcontroller things, you'll miss that USB connection. It's also more expensive to have that module built onto the board ($95 for the Uno + module, $150 for the Arduino Bluetooth, but I don't think you gain very much from that unless you have a really specific purpose in mind for the board.
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Nov 6, 2010 17:32
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Heran Bago posted:I want to pick up an Arduino starter kit, or one of some other micro controller or microprocessor that is easy to learn to program. If possible I'd like one that comes with bluetooth modules, otherwise I will just buy them separately. Are there any hiccups or specific processors I should expect to need if I want to communicate with bluetooth modules or are some modules straight-forward? If you've never touched this stuff go for the Arduino - it's an ATmega with a programming interface and preflashed bootloader. It makes it easy if you've never done this stuff before. If you decide you like Atmel microcontrollers then it isn't a big jump to working with plain ones later on. If you want to be really hardcore about it then get some PIC microcontrollers and an ICD3 
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Nov 6, 2010 18:53
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BattleMaster posted:If you want to be really hardcore about it then get some PIC microcontrollers and an ICD3 God, don't do this. Arduinos are so easy to work with, they're so great. Here's a related question that I've spent like 15 hours in the past week troubleshooting. What's the best setup for PIC programming? I'm using one of the 16-family MCUs with MPLAB. Also a PicStart Plus programmer. Why the hell don't multiple C files work properly? Why does MPLAB crash so often? Why is everything so bad? I even tried HI-WAVE and it still doesn't seem to handle multiple C and header files. It keeps on telling me that my functions are redefinitions. 
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Nov 7, 2010 04:49
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Believe it or not, PIC16s are set up in a way that makes C hard to implement well. They have weird non-contiguous memory segments and only one pointer register. So it's no surprise that there's no official C compiler and the unofficial ones that exist are rear end. Just switch to a PIC18 if you want good C support. The official compiler is really good and all you miss out on are a couple of the really hardcore optimizations if you go with the trial or student versions.
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Nov 7, 2010 05:07
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BattleMaster posted:Believe it or not, PIC16s are set up in a way that makes C hard to implement well. They have weird non-contiguous memory segments I forgot, I totally ran into this problem, too. One of my teammates wasted like a week of troubleshooting before he realised that lookup tables didn't work. BattleMaster posted:and only one pointer register. So it's no surprise that there's no official C compiler and the unofficial ones that exist are rear end. It's still rear end, though. BattleMaster posted:Just switch to a PIC18 if you want good C support. The official compiler is really good and all you miss out on are a couple of the really hardcore optimizations if you go with the trial or student versions.  . This is a term project for school.
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Nov 7, 2010 05:15
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ante posted:The one I'm using with MPLAB is official, isn't it? It's third party, but included with MPLAB along with a number of other third party tools. I don't know what Microchip gets out of bundling them in, but they don't make them.
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Nov 7, 2010 06:42
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So I took the plunge and bought my first soldering iron. I need to remove some bad capacitors from a power supply and replace them. I got some solder wick and have been trying to remove the capacitors but I haven't had any luck. The solder on the board seems to be impervious to the iron. I pressed the wick into it for a few minutes and nothing seemed to happen. The iron seems to melt solder just fine when i tinned the tip, but does not seem to do anything to the solder on the board. Am I doing something wrong?
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Nov 7, 2010 20:37
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Maybe it was built using lead-free solder that has a higher melting point? Also on a related note, I once had a bitch of a time desoldering a heatsink that was through-hole soldered to a board. The heatsink was doing a great job of sinking the heat from my soldering iron. 
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Nov 7, 2010 20:39
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What temperature should I be running the Iron at? I had it at 500.
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Nov 7, 2010 20:41
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I have a bag of LEDs sitting around, I know they are WHITE and BLUE. Is there a way to tell what voltage/etc these things require? Any way to specifically tell what specs they are, etc?
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Nov 8, 2010 01:00
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mAlfunkti0n posted:I have a bag of LEDs sitting around, I know they are WHITE and BLUE. Is there a way to tell what voltage/etc these things require? Any way to specifically tell what specs they are, etc? Try this: http://www.daycounter.com/Calculators/LED-Tutorial-Calculator.phtml
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Nov 8, 2010 01:52
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You should be able to discover the LED's voltage drop by putting it in series with a high-ish value resistor and measuring the voltage drop across it. Not sure how you'd find out the current it's designed for, other than through experimentation with different resistor values. Once you find out the voltage drop, start out with a resistor that gives it less than 20mA of current and see if the brightness is satisfactory. If not, bump it up a little until it is bright enough. Edit: I'm lazy and I just assume all LEDs are 1.2V/20mA though BattleMaster fucked around with this message at 02:13 on Nov 8, 2010 |
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Nov 8, 2010 02:03
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Thanks! I am not really good with the terminology or anything with electronics, generally haven't delved that deep into it in the past, but I am taking more of an interest with it these days.
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Nov 8, 2010 03:29
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BattleMaster posted:You should be able to discover the LED's voltage drop by putting it in series with a high-ish value resistor and measuring the voltage drop across it. Not sure how you'd find out the current it's designed for, other than through experimentation with different resistor values. Once you find out the voltage drop, start out with a resistor that gives it less than 20mA of current and see if the brightness is satisfactory. If not, bump it up a little until it is bright enough. Blue and white are usually a little bit higher (closer to 3V maybe?). http://www.maxim-ic.com/app-notes/index.mvp/id/3070 Most multimeters have a diode settings that will measure the forward voltage, and light the LED slightly. I've only used them for low-voltage LEDs, but I suspect they'd work for higher voltage ones like the blue and white. Delta-Wye fucked around with this message at 10:34 on Nov 8, 2010 |
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Nov 8, 2010 10:31
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Multimeters usually output something like 1.6V on the diode tester... high end models probably have a higher voltage options. -- I know this is a long-shot but does anyone know a way of getting NEC service manuals? I've been calling all day to their German headquarters as well as the Swedish repair centre, and they plain refuse to send them to outsiders. If anyone has any connections or something like that and could get me the schematic PDF for the MultiSync V921 Model N903 it would really get us out of a tricky situation here. There is one site that has the V921-1, this is a different board, googling results in a PDF of the service manual but the schematics are too small to read so it's useless. We use CRT monitors to train students in fault finding, and we thought we had the correct manual, but it was for a different system board, without this we're pretty much SOL...
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Nov 8, 2010 14:39
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longview posted:Multimeters usually output something like 1.6V on the diode tester... high end models probably have a higher voltage options. According to this, the one and only google result for ext:pdf MultiSync V921 N903 ftp://ftp.abcdata.com.pl/NEC-Mitsubishi/Certyfikacja/NEC%20CRT/19%20inch%20CRT/v921/v921_N903_.pdf It seems like the Original Design Manufacturer for that model is "Compal Electronics", wikipedia link: http://en.wikipedia.org/wiki/Compal_Electronics company website:http://www.compal.com/index_En.htm Of course neither of those has any pdf's pertaining specifically to Multisync V921 Model N903. In fact site:compal.com and any of those keywords or combination thereof turns up nothing in google. Still could try emailing compal. Let me know if any of this is helpful at all.
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Nov 8, 2010 20:35
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The Scientist posted:According to this, the one and only google result for ext:pdf MultiSync V921 N903 Thanks, I've sent them an email, though at this point I'm not expecting much... If this doesn't turn out, we'll have to look into other devices to teach with, any suggestions for something roughly as complex as a CRT which is also possible to get schematics for? Obviously anything surface mount is out...
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Nov 8, 2010 23:05
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SeldomSeen posted:What temperature should I be running the Iron at? I had it at 500.
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Nov 9, 2010 14:19
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I just did a repair on a Dell 1150, the power jack had come loose. I can see why now, the power jack barely anchors to the motherboard and the most minimal amount of solder was used to hold them in place. Removing solder from tiny through holes is a tough job at times.
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Nov 9, 2010 15:30
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At my school, rather than having lab be part of the regular course, we have these multi-disciplinary engineering labs where they try to make us do projects that are more realistic rather than just "measure resistor with scope". Anyway, we got behind in my circuits class, and ahead in my lab, so this week in lab we're doing filters, and we haven't gotten there in circuits yet. Part of the pre-lab is to figure out what these circuits do (high-pass, low-pass, or band-pass): I'm told its easy to figure out with laplace transforms, but again, we haven't gotten there yet (we just started talking about converting circuits into the frequency domain to make finding capacitor and resistor currents easy). Can anyone help me out?
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Nov 11, 2010 01:10
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Mill Town posted:Lead free on metal boards... Sounds a lot like my last job. You wouldn't happen to be in the LED lighting industry would you? Haha, got it in one. Spent most of today cursing Luxeon Rebels for the perversely designed things they are.
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Nov 11, 2010 02:04
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Aluminum Record posted:At my school, rather than having lab be part of the regular course, we have these multi-disciplinary engineering labs where they try to make us do projects that are more realistic rather than just "measure resistor with scope". Anyway, we got behind in my circuits class, and ahead in my lab, so this week in lab we're doing filters, and we haven't gotten there in circuits yet. Part of the pre-lab is to figure out what these circuits do (high-pass, low-pass, or band-pass): The rule of thumb I try and use is to remember inductors are "shorts" to LF values and "opens" to HF values, and capacitors are "shorts" to HF values and "open" to LF values (opposite of each other). What actually consists of HF and LF depend on the values present, and they are never really shorts or opens, but it's a good enough approximation to decide if a particular arrangement is HP, LP, BP, or bandreject. Looking at your first example, it has a inductor to ground. Inductors look like opens to LF frequencies, so they will be shunted. They look like opens to HF frequencies, so they will be passed, so I would reckon that it is a high-pass. Delta-Wye fucked around with this message at 02:22 on Nov 11, 2010 |
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Nov 11, 2010 02:17
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Delta-Wye posted:The rule of thumb I try and use is to remember inductors are "shorts" to LF values and "opens" to HF values, and capacitors are "shorts" to HF values and "open" to LF values (opposite of each other). What actually consists of HF and LF depend on the values present, and they are never really shorts or opens, but it's a good enough approximation to decide if a particular arrangement is HP, LP, BP, or bandreject. Duh, that makes sense, I knew that too. Going by that logic... In the second one, the cap would kill high frequencies, and the inductor would kill the low frequencies, so I'm thinking band-pass. In the third one, depending on the cap values, it seems like the right cap would be the one thats really gonna decide the output, with a cap looking like an open at LF, it'll only develop a voltage drop across it when the frequency is low, so I would say low-pass. I think the last one is another band pass.
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Nov 11, 2010 03:09
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Aluminum Record posted:Duh, that makes sense, I knew that too. Going by that logic... Look at #3 as two lowpass filters in series - the first one shunts HF and passes LF. The second one takes that new signal, shunts HF and passes LF to the output. There are a few reasons for such a layout, perhaps they needed greater rolloff or something, sometimes you need multiple poles, I don't know. To tell the truth, I would need to do a bunch of reading if I was going to do anything more specific than some handwaving You have the basic idea though.
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Nov 11, 2010 06:44
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Aluminum Record posted:Duh, that makes sense, I knew that too. Going by that logic... number 3 is just 2 low passes one after the other. Making a net low pass. the last one is a high pass. The cap filters out lows, and the inductor also filters out lows.
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Nov 11, 2010 06:46
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Aluminum Record posted:At my school, rather than having lab be part of the regular course, we have these multi-disciplinary engineering labs where they try to make us do projects that are more realistic rather than just "measure resistor with scope". I've lost track of how many times I had to bias a transistor for some lab or homework assignment. Guess how many times I have ever had to bias a transistor in real life.
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Nov 11, 2010 16:10
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Hillridge posted:I've lost track of how many times I had to bias a transistor for some lab or homework assignment. Guess how many times I have ever had to bias a transistor in real life. I spend a couple hours a day tuning biasing networks on transistor amplifiers and filters. I didn't learn how to do it in any class, but still. Zaxxon posted:the last one is a high pass. The cap filters out lows, and the inductor also filters out lows. ANIME AKBAR fucked around with this message at 06:01 on Nov 12, 2010 |
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Nov 12, 2010 05:58
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Number 3 looks like a phase shifter to me.
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Nov 12, 2010 18:28
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First off, I really know nothing about electronics. Can LEDs take a tiny bit of extra voltage? I bought 3 radioshack 276-0143 infrared leds. They have a forward voltage of 1.2v and current of 100ma. I bought a 4AA battery box, and soldered a wire in place of where one of the batteries would go, so it should be 3AAs at 1.5 for 4.5v. The leds will be getting .3 extra volts, so is that ok?
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Nov 14, 2010 18:14
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ease posted:First off, I really know nothing about electronics. A diode isn't like a resistor. With a resistor, if you apply 5 volts over a 1 ohm resistor, you get 5 amps of current through the resistor. If you apply 3 volts, it gets 3 amps -- the operating principle being voltage = current * resistance (V=IR). A diode doesn't have that linear characteristic. Instead, it has an exponential curve where a small change in voltage can produce a large change in current. The way we deal with this is to add a resistor in series with the LEDs to limit the current to a safe value. Using this calculator, I get a value of 10 ohms for that resistor.
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Nov 14, 2010 19:01
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ease posted:First off, I really know nothing about electronics. An LED, along with most electrical components, doesn't create or destroy energy, they convert it to other forms (as the axiom says). An LED might be emitting photons as one method of converting energy to another form, but along with that, it also releases heat. If the voltage is too great, the heat emitted would be greater as well, which increases the chances of failure (meltdown). Also, if Voltage is the ability for electricity to overcome resistance (in really, really simplified terms), then the over-voltage could, conceivably, overcome the "gaps in conductive materials" that make up the inner workings of the LED (again this is super simplified), which would render it useless, or at least less efficient. That being said, I personally wouldn't be worried about a .3 volt excess. But I'm very much NOT a professional, like these other gentlemen. In fact, most of the stuff I build doesn't work. Of course, decreasing the voltage that the LED's see would be as simple as putting them in series with a resistor that provides a .9 volt total voltage drop. By in series, I mean, somewhere along the path that the current flows in the circuit that powers the LED's. In other words current has to flow through BOTH the Resistor and the LED's. edit: You ever happily anticipated someone telling you exactly how and where you're wrong? 
whose tuggin fucked around with this message at 19:11 on Nov 14, 2010 |
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Nov 14, 2010 19:04
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Thanks for making so I could understand that, at least I think I have a idea of what you are getting at, and know that a resistor is definitely required. That calculator is rad.
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Nov 14, 2010 19:47
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I can't remember the name of the site, but what they do is let people send in schematics for a pcb and wait till they get enough and then do a mass bulk printing and it's really cheap. Anyone know what site I'm talking about?
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Nov 15, 2010 02:03
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CowGuy posted:I can't remember the name of the site, but what they do is let people send in schematics for a pcb and wait till they get enough and then do a mass bulk printing and it's really cheap. Anyone know what site I'm talking about? BatchPCB, run by Sparkfun.
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Nov 15, 2010 02:10
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I have 2 questions: 1. I was wondering if anyone could clarify the process of do-it-yourself PCB etching. At my local radio shack they sell etching solution, but what do I use it on? Like a sheet of solid copper? 2. Also I'm trying to learn how to implement stepper motors. I'm curious about the order in which you induce current through the respective coils. for instance, I have a 6 lead stepper (I guess its technically a 5 lead, because two of the leads are shunted). I've taken a multimeter and measured the resistance of the coils, so I kind of have a feel for which ones are pairs (I hope), but because I don't have access to a stepper controller, I don't know how to build a simple learning circuit that successfully makes the thing turn in one direction or the other, just to get an idea of the principles in operation. I've looked over the Wikipedia page, a pretty detailed guide I found on google, and my Intro to Electronics textbook and an "electronics and nuclear power dictionary" I have, which is admittedly pretty old. Never been able to set up a test rig on a breadboard that makes the thing turn in a single, continuous direction. I'm anticipating an answer in the form of a resource or some documentation since its such an in-depth subject.
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Nov 15, 2010 02:39
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The Scientist posted:I have 2 questions: The Scientist posted:2. Also I'm trying to learn how to implement stepper motors. I'm curious about the order in which you induce current through the respective coils. for instance, I have a 6 lead stepper (I guess its technically a 5 lead, because two of the leads are shunted). ABCDABCDABCD...etcetc. If you are on step 'C', for instance, connecting C or A to +V will do nothing, whereas connecting B will make it turn one way and D the other. Some quick experimentation will get you turning it in the correct direction constantly. You can also connect the center-tap leads to +V and connect the coil wires to ground - this makes using low-side switching n-channel mosfets super easy. Changing the polarity just changes the direction for the same step order, so it's pretty flexible.
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Nov 15, 2010 02:50
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i found this thing in the class trash pile (in packaging and everything!) http://olimex.com/dev/pic-web-reva.html whatever shall i do with it! i've never done PIC before.
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Nov 15, 2010 15:18
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Frobbe posted:i found this thing in the class trash pile (in packaging and everything!) That's a hell of a thing to find in a trash pile. Kind of advanced if you've never worked with PICs before, but it has a button and LED on it that you can play with until you get the basics down and can move onto the ADC, serial port, and ethernet stuff. When you get far enough you should make a program that serves up a webpage with the temperature reading from the thermistor displayed. That would be my first major project because it has everything needed for that on board.
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Nov 15, 2010 16:16
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