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therunningman posted:Does anyone know a source of cheap 1P10T rotary switches? I am having a tough time finding a place that won't charge and arm an a leg per. Digikey has a few in the $5 range; CKN9478-ND, for example.
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Mar 30, 2010 06:34
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ShoulderDaemon posted:Digikey has a few in the $5 range; CKN9478-ND, for example. Thanks. I forgot to mention I need panel mount switches though.
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Mar 30, 2010 06:36
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therunningman posted:Thanks. I forgot to mention I need panel mount switches though. GH5603-ND, $11.
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Mar 30, 2010 06:41
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Hey guys. I'm currently in the process of restoring a 1940's Silvertone radio/45rpm Record Player. Here's the original photoshop of my idea. I'm adding the avr32 ngw100 board as my microcontroller, and on top of that I'm adding an homemade board that has a ac97 codec for audio. I'm going to add 6 IN-4 nixie lights for a clock, plus 4 IN-13 tubes for a vu bargraph. On top of that it will have rca out, plus a dual am and fm transmitter; so, I can play my mp3s to other antiques around the house.  My question is: I accidentally broke one of the knobs/switches, and want to replace it with something that better fits its functionality. I'm trying to find a rotary switch that Single-Pole and two or three throw. I'm also looking for a near impossible feature. I want it to be self righting/center/neutralizing. So I can get knob that looks similar to an arrow and you can use it to go through the directory tree. I could get a SP3T rotary switch, but it would require manual effort to center the knob. fake edit: should I make a thread over the project? Entone fucked around with this message at 00:19 on Jun 2, 2017 |
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Mar 31, 2010 22:05
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Entone posted:Hey guys. I'm currently in the process of restoring a 1940's Silvertone radio/45rpm Record Player. Here's the original photoshop of my idea. I'm adding the avr32 ngw100 board as my microcontroller, and on top of that I'm adding an homemade board that has a ac97 codec for audio. I'm going to add 6 IN-4 nixie lights for a clock, plus 4 IN-13 tubes for a vu bargraph. On top of that it will have rca out, plus a dual am and fm transmitter; so, I can play my mp3s to other antiques around the house. Yes, please make a thread! To answer your question, here is a spring-return 3P3T part, on which you could just ignore two of the poles: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=E3G0603N-2-ND Edit: Oh wait, I didn't see that price.  Someone must have this sort of thing cheaper!
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Mar 31, 2010 22:23
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I found this (and others) with a quick google search of "spring return rotary switch": http://www.cole-switches.com/Products/1800return.html no idea on prices, but it looks like you should be able to find them somewhere. Cool project! I have 4 giant alphanumeric tubes that I'm going to make something with, I just haven't been inspired yet.
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Mar 31, 2010 22:49
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Thanks for the quick answer on calling the rotary switch, spring returned. I think I found a cheap one here. Titled (SWR) 70281-F1C . As long as the springs don't leave it in position 1 I'm happy. New thread here Entone fucked around with this message at 02:02 on Apr 1, 2010 |
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Mar 31, 2010 23:53
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I'm not sure where to ask this so I'll try here first. http://books.google.com/books?id=i-gABmh50v8C&printsec=frontcover&dq=iphone+hacks&ei=dPq0S9vPHaPszATNn6zQBg&cd=1#v=onepage&q=serial&f=false I'm building a gadget that replicates the iPhone serial->headphone/microphone communication hack in this book, except it uses an Atmel XMega A3 microcontroller instead of the Cypress microcontroller+FPGA chip that they use. In their circuit, they have resistors and capacitors in between their chip and the iPhone audio lines. The XMega has DAC and ADC circuitry however, whereas in their chip they're implementing the DAC and ADC stages in the FPGA portion of the chip. Do I need these resistors and caps also to avoid damaging my iPhone, or are the XMega's ports already safe?
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Apr 1, 2010 21:04
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Could you post an image of the schematic? Resistors and caps on a line between two devices sounds a lot like filtering to me.
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Apr 1, 2010 21:30
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Hillridge posted:Could you post an image of the schematic? Resistors and caps on a line between two devices sounds a lot like filtering to me. The FSK block at the top:  More info here: http://www.perceptdev.com/labs/iphonehacks They're doing a very simple serial protocol using 4 kHz and 8 kHz as 0 and 1 if it matters. Also they're running the board at 5V and the XMega will be running at 3V.
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Apr 1, 2010 21:36
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I'm trying to make a 60V DC power supply for using a wall outlet to charge batteries and I'm not sure how to get to 60V after rectifying with that square root of 2 factor. Any ideas?
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Apr 2, 2010 00:10
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dxt posted:I'm trying to make a 60V DC power supply for using a wall outlet to charge batteries and I'm not sure how to get to 60V after rectifying with that square root of 2 factor. Any ideas? Wall power should be 120V RMS, or 170V pk-pk. It should rectify to pretty close to 60VDC.
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Apr 2, 2010 00:32
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just get a step down transformer, or wind your own.
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Apr 2, 2010 04:05
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babyeatingpsychopath posted:Wall power should be 120V RMS, or 170V pk-pk. It should rectify to pretty close to 60VDC. That's not peak to peak!
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Apr 2, 2010 05:31
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King Nothing posted:The FSK block at the top: The input circuit is biasing the analog-to-digital converter to the halfway point (1k to +5v, 1k to gnd) so that the single-sided supply for the uC can capture the full waveform. The cap size they have chosen also filters out a lot of the bass. The output circuit is a very large voltage divider, presumably because the output would be full-scale (0-5v) and that's absolutely huge for a microphone input. It's also cap coupled. I wouldn't change too much with those circuits, though it will depend on the analog circuitry of the Xmega a bit. You might need to make the voltage divider on the output not so steep, since you're only at 3.3v. Maybe 150k instead of 220k.
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Apr 2, 2010 15:56
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Rescue Toaster posted:The input circuit is biasing the analog-to-digital converter to the halfway point (1k to +5v, 1k to gnd) so that the single-sided supply for the uC can capture the full waveform. The cap size they have chosen also filters out a lot of the bass. Yeah, 5V on that voltage divider will produce about 22mV on the FSKOUT side, so I'll probably use a smaller resistor than 220K there. A few more questions: Can you explain more what "biasing the analog-to-digital converter" means? Or post a link explaining it? What exactly depends on the XMega's analog circuitry? Why is the FSKOUT cap 0.1uF and the FSKIN cap 0.2uF? Thanks!
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Apr 2, 2010 17:12
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The 0.2 uF capacitor removes the DC component from the incoming signal, and the resistor network re-establishes it at a value of half the supply voltage on the micro side, which will be in the centre of the ADC sampling range. 1K is pretty small for biasing. The value needs to be chosen in relation to the output impedance of the driving circuit, as well as the impedance of the cap at the frequencies of interest.
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Apr 2, 2010 23:08
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babyeatingpsychopath posted:Wall power should be 120V RMS, or 170V pk-pk. It should rectify to pretty close to 60VDC. wow how did I forget that, that makes things much easier.
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Apr 3, 2010 02:55
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dxt posted:wow how did I forget that because it's incorrect, as catbread pointed out it's 170V peak, 340V peak to peak. you'll need a step down transformer, or a fancy switching supply to get 60V without dissipating a huge amount of power. and in any case you'll want a transformer for isolation, at least.
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Apr 3, 2010 16:34
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I meant the rms part, I realise the pk to pk was wrong. I was planning on getting a step down transformer and rectifying it, not too worried about power losses at this point, besides making sure the diodes can handle it.
dxt fucked around with this message at 17:47 on Apr 3, 2010 |
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Apr 3, 2010 16:56
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I'm just starting out in electronics and am taking course on it at my college. I picked up an arduino for fun little projects but my current project might be a little ambitious for my skill level, as apparently I cannot get it to work. I'm trying to use the arduino to switch a SSR on or off. I'm using the button circuit on the arduino tutorial and the script to make it a simple on/off switch. Here is exactly what my arduino circuit looks like:  I'm pretty sure the arduino circuit is working right because it turns leds on and off like it should. Rather than connecting the leds to pin 13, I'm trying to connect the SSR. Here is the whole rig I have setup. Right now I'm trying to control outlet number 8 on this DJ power center. I am attaching the white wire before the switch, this way the neon bulb in the rocker switch will not light unless the SSR is giving power to it. Then if I wanted to I could manually override the SSR's on/off setting by switching the rocker switch as well. My problem is that when I power up the DJ power strip and arduino, the switch is lighting regardless of arduino's settings. The current is passing right through the SSR. I figure either the SSR's default setting is closed and I'm not passing enough voltage to the SSR to get it turn off, or my wiring is messed up somewhere else.  Click here for the full 1600x1067 image. The numbers in the picture are: 1: switch and eventually load 2: power source 3: pin13 on arduino, switches state from HIGH or LOW. 4: ground I've seen the arduino control this exact model of SSR before, so I think it should be able to, I assume I'm just doing something wrong here. EDIT: Never mind, the problem is that I had nothing plugged into the outlet. It works perfectly when I plug a lamp into the outlet. ludnix fucked around with this message at 21:29 on Apr 3, 2010 |
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Apr 3, 2010 18:31
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ludnix posted:Does the light go off if you disconnect the SSR from the Arduino? How about if you disconnect the high-voltage side of the SSR as well? If not, you've probably wired something wrong on the high-voltage side. Can you draw us a diagram of that?
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Apr 3, 2010 19:24
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So I've built my daughtercard for the de0 cyclone III dev board, and I'm testing it out and things are going well. However, when I was testing some code for interfacing with some quadrature encoders, I noticed that some of the user LEDs on the de0 board were blinking. They are, according to documentation, driven directly by the FPGA, but in my design I am not using those pins. So I tried tying those pins low in my design. Now those LEDs stay off, but a few other LEDs are blinking in a similar way. The blinking is definitely related to my program, (like one of them blinks every 16 encoder counts, another every 128). This is really baffling and either the documentation on the dev board is incorrect or my programming software (quartus II) is complete garbage.
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Apr 3, 2010 22:15
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What would be the longest distance I could (reliably) send a TTL level logic signal over CAT3 cable?
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Apr 4, 2010 16:58
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dv6speed posted:What would be the longest distance I could (reliably) send a TTL level logic signal over CAT3 cable? it all depends on what kind of bandwidth you need. there's nothing wrong with sending data for several miles, so long as you don't mind crappy data rates.
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Apr 4, 2010 19:41
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dv6speed posted:What would be the longest distance I could (reliably) send a TTL level logic signal over CAT3 cable? If you're running to something with a differential receiver on it (many FPGAs) or if you can make a little differential receiver on the line end, you could transmit a pair of complementary TTL signals to make sure noise pickup isn't a big problem. With that scheme you could go pretty far in a variety of conditions.
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Apr 5, 2010 06:06
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Bandwidth really isn't a concern. The application is basicaly a nurse call station like they have in hosipitals. If someone pushes a button it latches an alarm to the on state until someone else pushes a button to turn it off. (We are trying to get my grandmother out of the nursing home she's in and bring her home) So basicaly we are only talking 1 or 2 bits of data. I'm using logic signals because the system will become more advanced in the future as I want to play around with home automation. I was mostly concerned about voltage drop, but realisticaly the longest run I'll have would be something like 150 feet to put an alarm in my garage. CAT3/5 is the most convient cabling for me to use for the project since I already have a goot bit of it ran, and lots more sitting in boxes. Also, can anybody reccomend a good parts grab bag/kit? I have a variety of projects, mostly based around microcontrollers or PC interfacing and need a good variety of passives, diodes, transistors, etc. I'm very hesistant to buy those grab bags I see without talking to someone who's already gotten them. I fear they are just a way for the company to get rid of components with values so large or small that are taking up space on their shelves, and only a handfull of stuff I'll actually use. AbsentMindedWelder fucked around with this message at 14:43 on Apr 5, 2010 |
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Apr 5, 2010 14:40
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Is Sparkfun the best place for Arduino related projects, or is there a better place to buy them? We've started fleshing out the micro-controller class I'll be teaching this fall, and the owner of the center is leaning toward using some sort of Arduino setup. I've never used this particular micro, so I need one to play around with. I know there has been tons of Arduino discussion in this thread, but I don't want to try and sift through all the previous pages.
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Apr 5, 2010 16:31
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Re-posting my question here, as the quick questions thread (and 3 or 4 other electronics guys I know) couldn't ID what this was. Backstory: our dryer up and quit on us in the middle of running a load in our new house. Pulled off the back panel and got a big whiff of burnt, probably important, appliance guts. Took the thing apart and pulled out the control board to find this:  Rear view:  Board model number? google gave me nothing useful...:  I checked it with a multimeter and it read as 1.6K Ohms. It's been years since my college ac/dc EE classes, though, and I have no idea what that actually means as far as how to get this thing working again, or what to do about it. The part itself is around $200 apparently, which is more than I paid for the dryer to begin with. Surely in this wonderful age of fine electronical wizardry we can fix something as simple as this looks. Right? 
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Apr 5, 2010 18:05
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dv6speed posted:Bandwidth really isn't a concern. The application is basicaly a nurse call station like they have in hosipitals. If someone pushes a button it latches an alarm to the on state until someone else pushes a button to turn it off. (We are trying to get my grandmother out of the nursing home she's in and bring her home) I would recommend getting one of Jameco's kits for resistors and capacitors (something like http://www.jameco.com/Jameco/catalogs/c101/P51.pdf). They also sell nice drawer kits to hold them. It sucks digging through a grab bag looking for a particular value. For diodes, you can probably buy a dozen or so each of common ones and be pretty much good to go. Once again, dealing with a bag of diodes and looking for a particular one can be annoying. 4148s, 914s, and some combination of 4001s and 4004s should be plenty. Transistors are the same way, look around and some examples of the sort of thing you want to do and buy a selection. Some 2n3904/3906s, maybe some 2n2222s, maybe a few 2n7000 mosfets, whatever looks useful.
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Apr 5, 2010 19:47
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I don't think it's worth keeping big quantities of assorted transistors or diodes on hand. In my personal experience it was worth the few dollars each that I spent on big bags of 1N4001 diodes, 2N3904 NPN BJTs, and 2N3906 PNP BJTs. If I ran into a situation where one of those didn't fit, it's because I needed something with very specific characteristics that I'll never need again.
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Apr 5, 2010 21:28
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dreggory posted:Re-posting my question here, as the quick questions thread (and 3 or 4 other electronics guys I know) couldn't ID what this was. The fact that the board itself is burning more than the resistor(which is still hold its proper value) tells me that the toasted resistor is a symptom, not the cause. Something else hosed up and is dumping too much current through it. Look for other problems like short circuited tracks, bad transistors, blown caps. Your multimeter should have a diode setting that can be used to test the transistors when they're not in the circuit.
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Apr 5, 2010 21:28
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Looking it over the only thing that's obviously odd is one cap that is bulging slightly. Other than that, and the charred spot, the board is pristine. The dryer itself was maybe 3 years old, and spent half its life in a garage, unused. I'll play around with the multimeter and see what I can find, though.
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Apr 5, 2010 21:52
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Hillridge posted:Is Sparkfun the best place for Arduino related projects, or is there a better place to buy them? If you just want the arduino board, Liquidware may be cheaper. If you want the board plus a bunch of crap, Sparkfun will be fine.
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Apr 5, 2010 22:19
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ante posted:The fact that the board itself is burning more than the resistor(which is still hold its proper value) tells me that the toasted resistor is a symptom, not the cause. I feel like a total  but how do you read the color codes on the resistor? It looks like Red-Yellow-White-Black to me, so if its a 4 band color code it should be 249. Am I reading it wrong? I suspect the 1.6K Ohms is the rest of the circuit in parallel.Has anyone seen a good guide for selecting transistors? I have a bit of a collection of different types, but other than NPN/PNP and current rating, I pretty much just grab whatever. MPSA42s are good for high Vce, for instance (been using them with Nixies) but some basic guide for when to use what, maybe a chart with important values pulled out of datasheets would be cool. Hell, if you guys want to come up with some 'important data' for transistors, I would be interested in making one. I feel like it is one area I am pretty ignorant about. Delta-Wye fucked around with this message at 22:47 on Apr 5, 2010 |
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Apr 5, 2010 22:32
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I've been googling for 2 hours. I think I'm using the wrong search times, and I'm not enough of an EE to figure this out on my own. What I'm looking for is a simple little circuit that has one logic output and 2 NO momentary push buttons. If you push button A the output will latch HI, and if you press button B, the output would return back to the LO state. I've found plenty of circuits that use only one button for toggling the output, but not 2. The circuits I've found using 2 buttons involve 1 NC momentary switch and 1 NO momentary switch, wired to 2 relays. I don't' really want to use 2 relays when I know this can be done with some creative use of logic gates in an IC.
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Apr 5, 2010 22:35
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dv6speed posted:I've been googling for 2 hours. I think I'm using the wrong search times, and I'm not enough of an EE to figure this out on my own. Unless I am mistaken, it sounds like you want an SR Latch, which may be constructed out of two NOR gates or two NAND gates depending on whether you want the inputs to be active high or active low. Two inputs, two complementary outputs, one of which may be ignored.
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Apr 5, 2010 22:41
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BattleMaster posted:awesomeness Now I have to dig out some books or do more googling and design the gates. Edit: 4001 FTW! Edit2: 4011 FTW! AbsentMindedWelder fucked around with this message at 23:44 on Apr 5, 2010 |
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Apr 5, 2010 22:49
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dreggory posted:Looking it over the only thing that's obviously odd is one cap that is bulging slightly. Other than that, and the charred spot, the board is pristine. The dryer itself was maybe 3 years old, and spent half its life in a garage, unused. I'll play around with the multimeter and see what I can find, though. Bulging caps could be your problem. When you're testing stuff, take it out of the circuit first. Delta-Wye posted:I feel like a total I read it as 1.9k which makes more sense if it was tested in parallel with the circuit, although I'd have a hard time justifying that. I don't think that amount of charring will change the resistor value, they're pretty sturdy.
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Apr 5, 2010 23:35
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OK, my SR NAND latch using a 4011 works perfectly. Upon being first powered on, the default output of the latch is HI instead of LO. Is this easy to change? In the real world all this would mean is when I first power on the circuit I'll have to hit the reset button to turn off an alarm. So it's not a really big deal considering the circuit will be on a UPS and probably never be turned off. But, if I can change that it'd be awesome.
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Apr 5, 2010 23:49
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