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You could do it with the encoder edges feeding a counter instead of polling them directly. The microcontroller would periodically read and reset it, then act on knowing the new wheel position and velocity.
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May 3, 2018 07:39
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Finally got the board and parts in to assemble the power supply I've been posting about in this thread for the last month or so - it worked perfect on the first go (thanks to this thread!), and in fact is significantly more efficient than LTSpice predicted - no-load current when it outputs 400V is 50mA vs. 250mA predicted (I was simulating it with worst-case values though). The only thing I hosed up was the size of one capacitor footprint, but I bodged another one in there well enough that you can't tell  The via stitching worked out great, though it was even more of a hassle to solder than I was expecting. I wound up buying one of these things: https://www.amazon.com/gp/product/B00BK772Y4/  Definitely recommend getting one if anyone here has trouble soldering SMD stuff on high heat capacity boards. I thought it would be poorly regulated and a pain to use, but it comes with thermocouples you put on the board itself so it regulates the temperature of the board rather accurately, and the small one I got doesn't actually radiate that much heat up into my face when I'm working over it - my little desk fan was more than enough to keep me comfortable while working on it for hours. You just set the thing to heat the board to like 90C, then do the heat pencil reflow soldering technique normally and it's like the board's heat-sinking isn't even there. Plus the sides and top don't even get burning-hot like I was expecting so I didn't even burn my arms when I accidentally rested them on the edges several times 
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May 10, 2018 14:41
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I spun my first PCB yesterday and ordered from OSH Park. I never want to touch Fritzing again. I'm installing KiCad tonight and trying to duplicate the same work. Fritzing worked for getting it done fast but there was so much I could do schematically, and certain things seemed overly difficult in layout.
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May 10, 2018 20:57
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Quick question, I bought these in an attempt to reverse engineer the RF remote for my ceiling fan (for home automation), only to discover afterwards that the remote is actually 303.875mhz. As far as I can tell, no one makes little breakouts like these for 303mhz. So if I got the correct crystal and soldered it in place of the 433mhz one on the TX, is it likely to work? I realize that doesn't help with the RX piece, but I think I can just use a SDR to decode the current remote.
CheddarGoblin fucked around with this message at 04:03 on May 15, 2018 |
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May 15, 2018 04:00
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n.. posted:Quick question, I bought these in an attempt to reverse engineer the RF remote for my ceiling fan (for home automation), only to discover afterwards that the remote is actually 303.875mhz. As far as I can tell, no one makes little breakouts like these for 303mhz. So if I got the correct crystal and soldered it in place of the 433mhz one on the TX, is it likely to work? I realize that doesn't help with the RX piece, but I think I can just use a SDR to decode the current remote. Probably, I've used those 433mhz circuits plenty and they're very simple (just turning the crystal on and off with a transistor), but you might need to adjust the coil or capacitor (I think there's one or two caps on the other side of the board) too for it to transmit any appreciable distance. It also will probably be out of tune without adjusting those but in my experience the things output such a massive wide band (like 2 to 3MHz wide) that that doesn't really matter much for most cheap receivers
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May 15, 2018 04:37
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I did a dumb. For some reason I thought I could control a pair of Peltier devices using a pot. Several sparks and flashes later I realized how immensely stupid that was.
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May 20, 2018 09:37
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Captain Capacitor posted:I did a dumb. I mean you probably could, it would just need to be one of those huge ones that you see in old 50's control rooms e: Like this one, available for the low low price of only $517!
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May 20, 2018 19:38
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Can someone tell me if I'm reading this wrong? I'm looking at this page about filters for switching power supplies: http://www.analog.com/en/technical-articles/designing-second-stage-output-filters-for-switching-power-supplies.html There's a long list of equations you're supposed to plug in to each other to make this one final super-equation, number 16:  It seems to me like the bottom line of that should be c2+d2, since otherwise equation d isn't used at all (either here or anywhere else on the page). Is this just a typo or am I missing something?
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May 25, 2018 19:14
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ate all the Oreos posted:Can someone tell me if I'm reading this wrong? I'm looking at this page about filters for switching power supplies: googled "rload rfilt" for a similar equation and found the author writing it was an editing mistake: https://ez.analog.com/thread/96284-ripple-filter-damping-techniques#comment-310514
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May 25, 2018 19:24
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hifi posted:googled "rload rfilt" for a similar equation and found the author writing it was an editing mistake: Oh neat, I didn't think to google the variable names, thanks! It's still giving me weird impossible numbers (it's telling me to set capacitor C2 to be 6 orders of magnitude smaller than C1, to something like half a pf, which doesn't seem... right) but at least now I know that's my fault
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May 25, 2018 20:31
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Maybe the wrong thread to ask in, and maybe my google-fu is just THAT weak, but I can't for the life of me find DIY headphone kits. Surely these exist? E.g. buncha wires, maybe even soldered onto a bluetooth thingy and/or headphone jack, plus all the stuff that goes in the actual enclosure, but without the enclosure itself...?
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May 26, 2018 00:33
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Switzerland posted:Maybe the wrong thread to ask in, and maybe my google-fu is just THAT weak, but I can't for the life of me find DIY headphone kits. Surely these exist? Do you mean a headphone amp kit, or like a kit to actually put together a... set of headphones? Because headphone amps are all over the place, I'm pretty sure someone put together a really fancy one in this very thread a year or two ago, but I've never heard of DIY headphones themselves
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May 26, 2018 00:53
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A kit to put together an actual set of headphones. As in, wiring, soldered headphone jack, the speakers, basically everything EXCEPT the actual enclosure.
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May 26, 2018 01:16
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Switzerland posted:A kit to put together an actual set of headphones. As in, wiring, soldered headphone jack, the speakers, basically everything EXCEPT the actual enclosure. Hm, yeah I've never seen anything specifically like that but I don't think it would be terribly hard to put together yourself - I know you can get complete bluetooth audio modules that handle the communication and amplification and stuff, just get a pair of speakers that'd fit whatever you're going to build this into, maybe a battery pack of some kind, and wire it up
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May 26, 2018 01:24
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If bluetooth isn't vital you're just looking at sourcing a pair of drivers, a jack, and some wire, anyway.
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May 26, 2018 01:26
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TerminalSaint posted:If bluetooth isn't vital you're just looking at sourcing a pair of drivers, a jack, and some wire, anyway. yes please? 
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May 26, 2018 01:28
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Loan some assembled headphones to a DJ, get separate components returned.
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May 26, 2018 01:30
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Switzerland posted:yes please? Come on dude we're not going to source your individual components for you.
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May 26, 2018 01:35
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Switzerland posted:yes please? https://www.aliexpress.com/af/headphone-speaker-unit.html?SearchText=headphone+speaker+unit&blanktest=0&origin=n&jump=afs Picking the right one is up to you because that gets into the dangerous waters of audio opinions. Lazy option for the wire and jack is cutting the end off an aux cable. TerminalSaint fucked around with this message at 01:45 on May 26, 2018 |
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May 26, 2018 01:39
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Switzerland posted:A kit to put together an actual set of headphones. As in, wiring, soldered headphone jack, the speakers, basically everything EXCEPT the actual enclosure. These guys make a kit that's supposed to be paired with housing and headband that you 3d print from their files (or get 3d printed by a service). It doesn't require soldering and I don't know anything about the quality of the hardware besides it existing: https://www.print.plus/store It's probably not what you want but it almost meets your original request.
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May 26, 2018 01:55
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hifi posted:googled "rload rfilt" for a similar equation and found the author writing it was an editing mistake: The guy helpfully posts a spreadsheet in that link you found which helped me figure out what was wrong - the article itself has a lot more problems than just the one: - There's an entire equation dedicated to finding ω0 and a bunch of equations right after that use a variable called ω, which isn't defined anywhere, so I assumed that meant ω0. Turns out ω is actually a symbol for "frequency in radians" that I didn't know about, which I assume is why you're supposed to go to college to learn this stuff - Equation 15 is actually supposed to be -RloadLfiltω2 Now it's finally giving me numbers that make sense 
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May 26, 2018 03:33
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Eh, I don’t think paying tens of thousands of dollars to know the symbol for frequency in radians is necessarily a great deal  How are you studying this stuff? When I was in school I think I learned far more from an experienced mentor and piles of application notes (from TI, AD, Linear, etc.) than class.
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May 26, 2018 08:58
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Class taught me to regurgitate a whole bunch of formulae, never use them again, and then struggle to understand them on wikipedia nearly a decade later
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May 26, 2018 09:32
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Not sure if this is the right thread. Does anyone have any experience with FPGAs. I'm trying to delay a fast(100s Mhz) signal a tunable amount, and it appeared that an FPGA could achieve this. However, I have almost no idea on how to achieve this. Any advice?
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May 30, 2018 02:48
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Er... what's your signal? FPGA's are awesome at digital signals. You can delay something by a precise cycle count and adjust it with inputs from other GPIO's. But if this is something with an analog component, an FPGA is going to be inappropriate. You might have some luck with Cypress PSoC's?
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May 30, 2018 03:01
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Spazzle posted:Not sure if this is the right thread. Does anyone have any experience with FPGAs. I'm trying to delay a fast(100s Mhz) signal a tunable amount, and it appeared that an FPGA could achieve this. However, I have almost no idea on how to achieve this. Any advice? What delay range are you looking for? Are glitches okay when adjusting the delay? There's probably an easier way than an FPGA, but I don't know what it would be.
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May 30, 2018 03:15
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JawnV6 posted:Er... what's your signal? Binary signal, variable duty cycle. Probably 10s to hundreds of ns on then off. Would be happy to find a non FPGA solution, but would like to be able to control delay with some kind of signal, say from an arduino. Delay would mostly be static or changed very slowly. i'm seeing something like this on digikey (https://www.digikey.com/products/en/integrated-circuits-ics/clock-timing-delay-lines/688/page/2), but they all seem surface mount.
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May 30, 2018 03:31
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You're going to have a hard time finding a non surface mount FPGA. Those look like the right ICs. If you can say, what are you trying to do on the grander scale? The delay you're talking about is ones through tens of cycles at a 100MHz sample rate.
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May 30, 2018 04:51
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Got a prototype of version 2 of my nixie display digit board assembled and running, but I couldn't shake the feeling that I had forgotten something in the design... Then I powered it off, grabbed the board, and it literally hit me - I forgot discharge resistors for the ~1.2uF of smoothing capacitors on the 180V rail
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May 30, 2018 14:54
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Came back around to the Mini-USB port swap again, once I figured out how to non-destructively disassemble my microphone. Anyone have a digikey part number for a micro usb port that might drop in written down somewhere?    
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May 31, 2018 00:20
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SwissArmyDruid posted:Came back around to the Mini-USB port swap again, once I figured out how to non-destructively disassemble my microphone. I don't know if anyone will be able to match it just from pictures, you might need to get in there with a micrometer and try to sketch out and dimension the footprint. At that pin pitch a few tenths of a mm can be the difference between "fits fine" and "pins overlap and short out". Even if you got the pins right you probably won't be able to find one that has anchor points at the same positions, meaning the micro USB port will be weak and prone to snapping off. A better option imo is to just replace that entire board - it looks like the PCB it's mounted on is only for the USB port and that little bypass capacitor there. You could just replace it with a different one that fits in the same space but with the correct footprint for a micro-USB port. Either etch one yourself, get one manufactured or try to rig it up some other way (maybe just solder wires directly to the port and glue the whole thing in place somehow?)
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May 31, 2018 00:36
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Nah I reckon you can get one close enough and make it work. The footprints are usually all pretty similar. I do agree that you should take some measurements though. Then go look on digikey for surface mount mini usb connectors and play match the drawings until it's close enough.
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May 31, 2018 00:43
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Splode posted:Nah I reckon you can get one close enough and make it work. The footprints are usually all pretty similar. The footprints are similar between mini and micro? I guess I've never actually bought mini-USB sockets but I thought they'd be a bit bigger than micro since the connector itself is bigger 
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May 31, 2018 03:41
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ate all the Oreos posted:The footprints are similar between mini and micro? I guess I've never actually bought mini-USB sockets but I thought they'd be a bit bigger than micro since the connector itself is bigger No I'm just dumb and didn't read the original post properly. I still think you could bodge it, but I am a professional bodger
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May 31, 2018 08:36
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so i have this, and i pretty much know i'm never going to do anything cool with it because i'm lazy, does anyone want it? 18.5-watt Soraa LED emitter. will need heavy heatsinking. 2700K color temperature.
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Jun 1, 2018 09:49
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Does anyone know of an online tool that lets you punch in an oddball resistance value you want and how many resistors you want to use and it tells you how to get closest to that value using a specified set of resistors (like E24, E96 etc) arranged parallel or series or both? Seems like something that would be super helpful... e: Like I tell it I want 5.5Ω using one resistor in the E24 range, it spits out 5.6Ω, for two resistors it spits out something like two 11Ω's in parallel, etc. Shame Boy fucked around with this message at 15:17 on Jun 4, 2018 |
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Jun 4, 2018 15:14
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ate all the Oreos posted:Does anyone know of an online tool that lets you punch in an oddball resistance value you want and how many resistors you want to use and it tells you how to get closest to that value using a specified set of resistors (like E24, E96 etc) arranged parallel or series or both? Seems like something that would be super helpful... This is as close as I could quickly find: http://jansson.us/resistors.html
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Jun 4, 2018 16:45
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Sir Bobert Fishbone posted:This is as close as I could quickly find: http://jansson.us/resistors.html Yeah that's pretty close to what I was thinking (and probably perfectly fine for what I'm doing) but now I'm interested in trying to make one myself, I imagine you could just generate a table of all possible combinations from n=1 to 4 for the different E ranges and then just do lookups on that. It'd probably wind up only being a few megabytes and would be very fast once generated. Add it to my pile of "stuff I'd like to do eventually" I guess 
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Jun 4, 2018 17:01
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I was pretty stoked to guess-and-check for dividing 3.3v down to 1.0v with 1k in series with 10k and 4.7k in parallel A good set of values
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Jun 4, 2018 19:13
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I think the answer is "eBay/AliExpress/disassemble a used monitor" but thought I'd ask: I'm going down the path of making a briefcase to hold my Amiga emulator, a la this, because I'm a massive nostalgia dork. I need a display module that will ideally handle an HDMI input since that's the only signal my emulator device outputs, which in turn means I need a way to bring the audio signal out from the display to a pair of small speakers. Given that I'll be using it exclusively for Amiga game emulation, I'm not looking for some high-performance display and have zero need for touchscreen capabilities. This guy would work well since it does HDMI and includes audio out, but it seems overpriced. Plus, I'd prefer something in the 13-15" range, which makes me think that my options are: 1) Cannibalize an old monitor which has either integrated speakers or (better yet) audio out 2) Try my luck with AliExpress items like this (which I know includes audio out because it's shown with speakers but has a massive bezel) or this (which should/might) or build-my-own combo of control board and display. Is there an option I'm overlooking, or some parts source I just haven't thought of? Thanks! late edit: seller "oupin6" on eBay is probably the best single source I've found so far, e.g. this and many other items. Little confused by his warning though -- I have no idea how to parse this: quote:PLEASE READ THIS CAREFULLY BERFORE YOU ORDER THE KIT: Trabant fucked around with this message at 20:39 on Jun 7, 2018 |
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Jun 7, 2018 19:00
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