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Stack Machine posted:If your circuit is generating the output, I'd connect the channels together, so downstream circuitry can use either the left or right. If it's necessary one channel be silent, definitely connect it to ground instead of just leaving it disconnected. It's the latter, before sending it on elsewhere, and OK, cool, thanks! Easy option it is, PCB ordered.
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May 2, 2021 15:13
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Can I ask a really dumb question: I want to use this thing I bought from adafruit, a tiny PCB that will play up to 11 samples with the closing of a switch (of 11 switches, one per sound), but I was thinking of trying capacitive switches. All the capacitive switch PCBs seem to be oriented toward use as numeric keyboards only(?) https://learn.adafruit.com/adafruit-audio-fx-sound-board/triggering-audio I'm seeing tons and tons of stuff like this on ebay: https://www.ebay.com/itm/400709646366?hash=item5d4c27f81e:g:6LMAAOSw8V9bSD5O  Is there any way of using this as a simple set of switches? Capacitive switches are cool looking. Here, maybe this: https://datasheet.lcsc.com/szlcsc/TTP223-BA6_C80757.pdf petit choux fucked around with this message at 18:28 on May 2, 2021 |
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May 2, 2021 17:20
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petit choux posted:Can I ask a really dumb question: I want to use this thing I bought from adafruit, a tiny PCB that will play up to 11 samples with the closing of a switch (of 11 switches, one per sound), but I was thinking of trying capacitive switches. All the capacitive switch PCBs seem to be oriented toward use as numeric keyboards only(?) There are 8 outputs for that grid of 16 buttons, which likely means the output is 4 rows and 4 columns for a matrix configuration, or if it's multi-touch compatible, then it's encoded (in which case I'm not sure why there are more than 4 outputs). Either way, you can convert that into a signal your adafruit board will understand with logic, but it basically comes down to understanding the datasheets for both the sides of the circuit. - what is the sound effect board expecting? If it's buttons shorting to ground, then you just need to produce a low voltage. If it's a button shorting to a logical high voltage, you need to know what that voltage is so you can find a compatible board for touch, or level shift it - what does the capacitive board output? How does it correspond to which button is pressed? What logic can you use to convert it to a one-hot signal for the sound board that's the appropriate voltage? These are questions and problems that are super appropriate for a beginner project, and will build skills that will help with future projects.
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May 2, 2021 18:34
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In the circuit schematic of the audio board up there you can see that the buttons are indeed active low. The capacitive switch module would have to have open drain outputs in order to be plugged directly into the audio board like that. I agree that there's probably some multiplexing going on given there are half as many outputs as buttons, so it's probably not as simple as just connecting the wires one to one. But it might be! Find a datasheet (this is the key word when looking for reference material for electronics parts) or a tutorial for that device to understand what sort of output it has. I also noticed that there's SCL and SDA pins on the sensor board, indicating that it's an I2C device, and the audio board has a serial connection. The most powerful way of connecting these together would be to put a microcontroller in the middle, just a regular Arduino or whatever, and write some code that reads all the inputs from the sensor board and triggers files on the audio board over the serial connection based on whatever logic you come up with.
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May 2, 2021 18:41
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petit choux posted:Is there any way of using this as a simple set of switches? Capacitive switches are cool looking. According to that datasheet, if you're OK using only 8 of the 16 switches, you can put that capacitive switch board in a mode that raises one of the 8 OUT1...OUT8 signals in response to touching switches 1 through 8 (you may have to take off a resistor connected from switch 2 to ground). If you need switches to ground to trigger that sample board from there, the easy way to do it is to just put an N-channel mosfet (like a 2n7000) on each switch, gate on the output from the OUT1...OUT8 from the switch board, source on ground, drain on the input to the sample board. As long as they both have the same ground this should work. If you want to use all 16 switches it's a lot more complicated. You'd need a microcontroller talking I2C to the switch board and using its GPIO pins to pull down on the inputs to the other board.
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May 2, 2021 18:44
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Maybe my ardor for the capacitative PCBs is cooling then. It would add to the latency anyway. I was also thinking I could try a printed PCB that has a strip of exposed foil for each trigger and a stylus going to ground. I think there's a couple simple devices like that out there. I'm a little flummoxed that there are all these keypads you can get for pennies and none of them can be used this way.
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May 2, 2021 19:53
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I can buy a strip of 10 of these and wire them individually, if I read this correctly. Says they can be used in "toggle" or "direct" mode, which I'm assuming toggle means a simple on-off switch? https://www.ebay.com/itm/2545661868...7Cclp%3A2334524
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May 2, 2021 19:57
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Ehh, pick up a bunch and play with them before committing them to any project. Good chance you'll spend five minutes with them while going "neat", but then your enthusiasm for using them in an actual project will naturally cool, 'cause they're a little crummy.
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May 2, 2021 20:15
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petit choux posted:I can buy a strip of 10 of these and wire them individually, if I read this correctly. Says they can be used in "toggle" or "direct" mode, which I'm assuming toggle means a simple on-off switch? The distinction between "toggle" and "direct" would usually be: Direct: button is active while being pressed -- instantaneous state Toggle: touching the button changes its state from active to inactive (or vice versa), and that state persists until the button is pressed again That's what I'd assume based on terminology alone, but sometimes things are inconsistent translations, so yeah, experiment if they're cheap.
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May 2, 2021 20:44
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Judging by this list of modes from the datasheet for those single-pad touch switches: what you'd want to interface with that sample board is direct mode, active low. As long as the supply voltages are within a ~0.6V range for everything you won't need additional components.
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May 2, 2021 20:51
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ante posted:Ehh, pick up a bunch and play with them before committing them to any project. Good chance you'll spend five minutes with them while going "neat", but then your enthusiasm for using them in an actual project will naturally cool, 'cause they're a little crummy. LOL probably. Well, they're on order. Stack Machine posted:Judging by this list of modes from the datasheet for those single-pad touch switches: drat, sweet. I was thinking of just taping this to the side of my drum machine when it's all together. Of course, in addition I'm probably going to try a handful of different input methods. I already have some very nice arcade buttons and they may be the simplest solution.
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May 2, 2021 21:22
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Hi! I have been hired for HR/manager role on electronic box build factory that produces box builds, wire harnesses etc. Now the employer doesn't demand any knowledge of electronics but I would still like to know as much as possible about the process. Any good resources or info about the subject. Any help would be much appreciated.
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May 3, 2021 19:09
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Trip report: Airgun-soldering QFN MCUs is significantly easier than QFP; it auto-centers, the pins don't bend, and the most common problem I had before (Shorts high on the pin) don't happen.
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May 3, 2021 22:41
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Here, I bought this for parts. $5, it's a little smashed. I'm disappointed that the joystick is actually the kind with switches, but it's still pretty good for one of those. Question: this thing apparently drives videocameras with variable 24ac current. so I think I'm safe to assume I can easily make that transformer into a 24v ac power supply as well, right? Anything else I should grab off this board?   
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May 4, 2021 20:41
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lunael1982 posted:Hi! Easiest answer is to throw on some EEVblog/Great Scott/ScanLime/Carl Brgeja/Electroboom/etc youtube in your background and you'll pick up some stuff by osmosis in the 1000 hours of content. There are a ton of books and stuff but for general learning I always recommend youtube because moving pictures are less boring for the beginner. I will gladly read research paper on RF antenna design but no way i'd recommend it to someone who wants surface level info. Sounds like general people making things youtube might also be more relevant that electronics directly. This Old Tony, AvE, Make it Extreme, etc. Lots of them out there that are wonderful if you avoid some of the dumber channels
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May 4, 2021 22:33
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petit choux posted:Here, I bought this for parts. $5, it's a little smashed. I'm disappointed that the joystick is actually the kind with switches, but it's still pretty good for one of those. Question: this thing apparently drives videocameras with variable 24ac current. so I think I'm safe to assume I can easily make that transformer into a 24v ac power supply as well, right? Anything else I should grab off this board? Definitely keep the transformer and fuse holder. That panel mount terminal strip might come in handy too. Those 3-terminal regulators (marked vr1, vr2, vr3) might be useful in the future but new ones are so cheap they're practically free. The yellow things that look like engorged ticks are tantalum capacitors and you should definitely not keep those because they're short circuits waiting to happen. Of the passives on the board the ones most worth saving are R12 and R17. I want to point out R4, R5, and R6 too. Not because they're worth saving but because lol. They're 0-ohm resistors. I guess these are used instead of the little steel wires because someone's pick-and-place machines couldn't handle bare wires with no bulge in the middle. M_Gargantua posted:Easiest answer is to throw on some EEVblog/Great Scott/ScanLime/Carl Brgeja/Electroboom/etc youtube in your background and you'll pick up some stuff by osmosis in the 1000 hours of content. I'll add to this that there's a whole genre of 'teardown' videos on youtube that are probably a good intro for someone going into manufacturing because it's basically just people taking things apart and musing about how they were built. These exist for virtually every class of electronic assembly that's been made, from chunks of spacecraft to consumer electronics, and are a good way to get exposed to the impressively diverse set of construction techniques that have been used over the years.
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May 5, 2021 00:13
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Stack Machine posted:Definitely keep the transformer and fuse holder. That panel mount terminal strip might come in handy too. Those 3-terminal regulators (marked vr1, vr2, vr3) might be useful in the future but new ones are so cheap they're practically free. The yellow things that look like engorged ticks are tantalum capacitors and you should definitely not keep those because they're short circuits waiting to happen. Of the passives on the board the ones most worth saving are R12 and R17. I so love this thread
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May 5, 2021 01:33
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Dominoes posted:Trip report: Airgun-soldering QFN MCUs is significantly easier than QFP; it auto-centers, the pins don't bend, and the most common problem I had before (Shorts high on the pin) don't happen. What about the EPAD?
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May 5, 2021 03:39
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So I shredded the above box, and I want to test this transformer. I don't know much about this stuff but I assume you have one a neg and a pos and a bunch of taps? I don't know what's what here but I've got a meter. Where should I connect the mains to start testing? (been drinking beer so I will not be connecting anything this evening) No, wait, not a neg and a pos and a bunch of taps but I'm trying to recall what these are. The fact that we've got the black and brown ones going to the bottom should be telling me something here, can't remember petit choux fucked around with this message at 05:04 on May 5, 2021 |
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May 5, 2021 03:52
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Can anyone clarify these ADC specs? Analog inputs, top-two pages: https://www.ni.com/pdf/manuals/374372a.pdf It states a bandwidth of 300 kHz, and yet a max sampling rate of 100 kS/s. I suppose the 300 kHz could represent the physical hardware LPF cut-off, but if the sampling rate can't go that high, this seems like a useless specification. This also plays into the listed system noise value of 0.4 mVrms, wherein its not clear which bandwidth this is based on.
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May 5, 2021 05:30
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Cyril Sneer posted:Can anyone clarify these ADC specs? Analog inputs, top-two pages: Apparently it's an analog frequency response thing, and not that uncommon to be much higher than practical (probably to keep the knee far away from the usable measurement range): https://ez.analog.com/data_converters/high-speed_adcs/f/q-a/141789/what-is-adc-bandwidth
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May 5, 2021 06:10
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KnifeWrench posted:Apparently it's an analog frequency response thing, and not that uncommon to be much higher than practical (probably to keep the knee far away from the usable measurement range): Yep, Nyquists
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May 5, 2021 06:21
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petit choux posted:Here, I bought this for parts. $5, it's a little smashed. I'm disappointed that the joystick is actually the kind with switches, but it's still pretty good for one of those. Question: this thing apparently drives videocameras with variable 24ac current. so I think I'm safe to assume I can easily make that transformer into a 24v ac power supply as well, right? Anything else I should grab off this board? I would keep the two XLR connectors on those cables too, they run $5-6 new. The silver one is a Switchcraft style and should come apart by loosening a set screw near the back to release the black rubber strain relief and another near the middle for the inner metal core, while the black (w/ red paint) one looks like a Neutrik and should come apart by twisting the plastic back shell and sliding the guts out. Both are easy to desolder the wires from the solder cups inside. The 3 pin one is standard for balanced audio or a single differential pair + ground like RS485. The 4 pin one is perfect for an RGB LED strip (RGB- and +12 or 24v).
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May 5, 2021 07:12
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ickna posted:I would keep the two XLR connectors on those cables too, they run $5-6 new. The silver one is a Switchcraft style and should come apart by loosening a set screw near the back to release the black rubber strain relief and another near the middle for the inner metal core, while the black (w/ red paint) one looks like a Neutrik and should come apart by twisting the plastic back shell and sliding the guts out. Both are easy to desolder the wires from the solder cups inside. Sweet, thanks! I think I'm going to photo stuff like this that I scrounge more often, I find some cool stuff now and then. But I guess I should reassemble this and plug it in and carefully apply the meter. I want to make a 24v ac power supply out of this and I still suspect it's set up for that pretty well. I'm sorry I can't figure out the wiring of the transformer just by eyeballing it, I don't really know much about this stuff, but I try not to let that stop me. And I still have a raccoon like fetish for exotic button panels and stuff. I've un-smashed this thing somewhat and the entire front panel look useable. The joystick is actually a clumsy set of 4 buttons but still, they look very solid. petit choux fucked around with this message at 07:47 on May 5, 2021 |
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May 5, 2021 07:42
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movax posted:What about the EPAD?
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May 5, 2021 10:28
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Where is the best place to buy DIY parts in bulk? As I get deeper into this stuff I am learning about projects that I can do but don’t have the parts to do them in my learner’s kits. I need to buy like a big box of assorted resistor, pots, tactile switches, caps, relays, etc for most of the projects I see. Unfortunately, I don’t have a local brick and mortar place.
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May 5, 2021 14:46
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Marsupial Ape posted:Where is the best place to buy DIY parts in bulk? As I get deeper into this stuff I am learning about projects that I can do but don’t have the parts to do them in my learner’s kits. If it is the second one, and you don't mind slow delivery just use aliexpress. Most assorted kits are some warehouse guys who buy off ali and resell.
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May 5, 2021 16:33
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lunael1982 posted:Hi! The best way to learn is to pick a project for something you think would be cool, and luckily this can be a pretty cheap hobby given that tis fun and you'll be the best HR person they've ever hired. The Arduino is a little computer-like thing that is design to learn how to build electronics. Here's a few Arduino based projects to do stuff that are cool and maybe relevant to your job: Since your job probably has a lot of CNC machines or automated equipment: https://www.youtube.com/watch?v=WKmzlMvxC7I Automatic Watering and Data Monitoring project: https://www.youtube.com/watch?v=O_Q1WKCtWiA And here's an Arduino 101 video: https://www.youtube.com/watch?v=nL34zDTPkcs Theres an Arduino-based project for any hobby.
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May 5, 2021 16:39
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VictualSquid posted:Actual bulk, as in 10000 each of each resistor value, or a big box of everything you need for tinkering? Yeah, I need a box o’ tinkering stuff. I’ll take a look there.
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May 5, 2021 17:59
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I'm with CFP - pick a project, come up with a design, and buy the parts for it. Buy more as required. I may be out of touch with this perspective, since it's common. IMO you'll learn more effectively, and be more likely to come up with something useful or novel if you build with a purpose.
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May 5, 2021 19:38
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Dominoes posted:I'm with CFP - pick a project, come up with a design, and buy the parts for it. Buy more as required. I get that completely. I just prefer to have very common things on hand instead of having to constantly order parts or drive over an hour to the nearest town with a hobby store.
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May 5, 2021 20:11
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ante posted:Ehh, pick up a bunch and play with them before committing them to any project. Good chance you'll spend five minutes with them while going "neat", but then your enthusiasm for using them in an actual project will naturally cool, 'cause they're a little crummy. the cool thing about capacitive switches is that you can roll your own to basically any configuration/specification for pennies, you'll learn a lot more about how they work and how to produce effective(-ish) designs. not as easy to get started, of course, but even if you decide they suck you'll have learned some really valuable stuff about capacitance that's universally-applicable in circuit design i really liked this https://www.renesas.com/us/en/docum...=en?language=en "Capacitive Touch Hardware Design and Layout Guidelines for Synergy, RX200, and RX100" as a guide for designing the sensors themselves, this https://www.cypress.com/file/73166/download "A Designer's Guide to Rapid Prototyping of Capacitive Sensors on Any Surface" is a good supplementary doc; all you really need in addition to basic electronics kit is some copper tape and/or a conductive ink pen and you're off to the races Ambrose Burnside fucked around with this message at 04:22 on May 6, 2021 |
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May 5, 2021 20:49
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petit choux posted:So I shredded the above box, and I want to test this transformer. I don't know much about this stuff but I assume you have one a neg and a pos and a bunch of taps? I don't know what's what here but I've got a meter. Where should I connect the mains to start testing? (been drinking beer so I will not be connecting anything this evening) If you put your multimeter in ohms mode, you can start figuring out which pins are on the same windings. Low resistance on 2 wires = same winding, near-infinite resistance = different winding. My guess is that black, brown, and red are each their own winding, and blue and yellow may be either a single winding with a center tap on yellow or yellow is a shield. You'll know yellow is a shield if it has high resistance to every other wire, and you'll know it's a center tap of blue if it has low resistance to both blue ones. The best way to find the primary is to see which of these windings was connected to the plug on the original equipment. It's likely (but not guaranteed) to be the one with the highest resistance. Once you've located the primary, you just connect your mains across the primary winding and measure the AC voltage across each secondary winding. There is one extra gotcha, though: there may be 2 primary windings. It looks like this equipment was designed to run on 120V or 240V, and that may or may not have required replacing the transformer. If you're in a 120V country, it doesn't matter. Just go through measuring the secondaries and if one is 120V it's probably the other primary. You can connect this in parallel with your first primary (stripe-stripe, solid-solid probably, but when in doubt check the way it was connected on the board) to increase efficiency under load. If you're in 240V-land you'll want to connect the 2 primaries in series before you run it, otherwise you'll be running everything at double voltage. Whatever you do don't just plug this unknown transformer straight into the wall! At the very least use a small fuse (like 1A) or a single fine strand of wire so if you accidentally try to use one of the secondaries as a primary, you'll immediately burn the fuse instead of your transformer. Best practice would be to use a variac or similar adjustable AC power supply so you can start at like 10V, but I get not everybody has one of those. Whatever you do, do it in an area where any sparking can be safely contained and don't move the meter probes while it's plugged in.
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May 6, 2021 03:18
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Microchip also has a lot of stuff on capacitive touch sensing out there. Like 20 years ago they were really big on the idea of using the most basic 555-timer-like method of sensing and a lot of their micros from that era had SR latch modules to support that along with the dual-comparators which most of their micros had and still have: from http://ww1.microchip.com/downloads/en/DeviceDoc/41328B.pdf The idea being that a given capacitance gives a square wave of a given frequency, which can be counted with a pair of timer modules - one in counter mode, one in timer mode. For a given period of the timer, the counter should read roughly the same value for a given capacitance. If a user touches the pad, the capacitance will increase and the frequency will decrease, meaning that the counter will read a lower number during a period of the timer. Microchip now puts fancier ADCs in their micros that can be configured to measure capacitance so you can measure one button per ADC channel:  Which would be ideal for the situation since most PICs have in excess of 10 ADC channels, but the first method is a fun (imo) and not terribly difficult exercise. You should be able to use a slightly non-standard 555 configuration to do that without one of the older SR latch PICs, by using the output to charge/discharge the capacitor while ignoring the normal discharge pin. (Though you can also do the SR latch method with newer PICs because the configurable logic cells have an SR latch mode.)
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May 6, 2021 03:25
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Stack Machine posted:If you put your multimeter in ohms mode, you can start figuring out which pins are on the same windings. Low resistance on 2 wires = same winding, near-infinite resistance = different winding. My guess is that black, brown, and red are each their own winding, and blue and yellow may be either a single winding with a center tap on yellow or yellow is a shield. You'll know yellow is a shield if it has high resistance to every other wire, and you'll know it's a center tap of blue if it has low resistance to both blue ones. Thank you so much for this response! What I've done so far is to reassemble everything, minus the enclosure, and eventually I'll try powering it and then checking all the wires to and from the transformer. It still has the og fuse so it's fairly safe. Then I'll cannibalize it one last time, maybe build a power supply or something from this transformer.
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May 6, 2021 03:45
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Ok, another possible future commercial project idea for future me or anyone interested: Automatic spice mixer. You put in spices in OOM 10 sep containers. Tell the device what's in each. Let's you automatically blend in arbitrary proportions, and result is by mass or volume. Probably needs some form of update cap or connectivity yo update presets. UI could be analog or digital physical sliders of each (think equalizer), or preset buttons/selector for things like "Italian seasoning", "chili powder" etc. Prior art: expensive commercial models where I'm not sure if they do this or something else. I am thinking consumer device <100 USD. Thoughts? Dominoes fucked around with this message at 17:33 on May 6, 2021 |
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May 6, 2021 17:28
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Dominoes posted:Ok, another possible future commercial project idea for future me or anyone interested: Automatic spice mixer. You put in spices in OOM 10 sep containers. Tell the device what's in each. Let's you automatically blend in arbitrary proportions, and result is my mass or volume. Probably needs some form of update cap or connectivity yo update presets. No market for it. The people that want this kind of thing already have all the individual spices. The people that are close to wanting it are almost certainly going to notice that "italian seasoning" and "montreal rub" are normal ingredients that can be bought at the store for very cheap. Among the list of everyone I know that uses spices, there is nearly zero overlap between the people who have everything individually and spice to taste and those that just grab the bucket of premix. You may run in different circles, though. Also, "tell the device what's in each" better not require user interaction in any way, because that's an effort bridge too far. The automatic bartender is only BARELY able to get away with it. For something like spices? You've got cumin. Whole? Ground? Powdered? What's the density of your powdered? Overall, I have always liked the "make a custom mix from bulk ingredients (WITH A ROBOT)" idea, but I've never been able to find a good application except for bartending and paint. WTF is an "OOM 10 sep container"?
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May 6, 2021 17:37
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If you add proprietary DRM'd spice cartridges to it that cost $20 each you have an idea that would make a bunch of VC money and then implode immediately on actual launch, if you're into that sort of thing.
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May 6, 2021 17:39
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Yeah that would be a good project to take to a VC firm and let some idiots give you a bunch of money, make a halfassed product, let it fail and take your million dollars you paid yourself and run.
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May 6, 2021 17:42
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lunael1982 posted:Hi! I keep meaning to get back to this post and forgetting, sorry. What do you mean by "box builds," like it makes boxes? Or it assembles things into boxes? Either of those and wire harnesses are somewhat more specific domain knowledge than general electronics I'd think. There'd be a lot more focus on wire selection, insulation types, connector types, crimp tooling, proper sealing if it's gonna be exposed to moisture etc. I mean still check out general electronics stuff (like the ones already mentioned, or maybe pick up a copy of The Art of Electronics textbook if you want something that just covers goddamn everything) but it kinda sounds like the job's going to involve a lot of the sort of knowledge you'd prolly mostly learn on the job by asking people and watching the work get done 
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May 6, 2021 17:47
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