Thread fatigued:>>2539950>I'm new to electronics. Where to get started?It is an art/science of applying principles to requirements.Find problem, learn principles, design and verify solution, build, test, post results, repeat.>Incredibly comprehensive list of electronics resources:https://github.com/kitspace/awesome-electronicsAdditional resources below:>Project ideas:https://adafruit.comhttps://instructables.com/tag/type-id/category-technology/https://makezine.com/category/electronics/https://hackaday.io>Don't ask, roll:https://github.com/Rocheez/4chan-electronics-challenges/blob/master/list-of-challenges.png>Archive of Popular Electronics magazines (1954-2003):https://worldradiohistory.com/Popular-Electronics-Guide.htm>Microchip Tips and Tricks PDF:https://ww1.microchip.com/downloads/en/devicedoc/01146b.pdf>Li+/LiPo batteries required reading:https://www.elteconline.com/download/pdf/SAFT-RIC-LI-ION-Safety-Recommendations.pdf>Books:https://libgen.rs/>Principles (by increasing skill level):Mims III, Getting Started in ElectronicsGeier, How to Diagnose & Fix Everything ElectronicKybett & Boysen, All New Electronics Self-Teaching GuideScherz & Monk, Practical Electronics for Inventors (arguably has minor issues with mains grounding)Horowitz and Hill, The Art of Electronics>Recommended Design/verification tools:KiCAD 6+CircuitmakerLogisim Evolution>Recommended Components/equipment:OctoparteBay/AliExpress sellers, for component assortments/sample kits (caveat emptor)Local independent electronics distributorsladyada.net/library/procure/hobbyist.html>More related YouTube channels:mjlortonjkgamm041EcProjectsPhotonvidssdgelectronicspaceworldwide>microcontroller specific problems?>>>/diy/mcg>I have junk, what do?Shitcan it>consumer product support or PC building?>>>/g/>household/premises wiring?More rules-driven than engineering, try /qtddtot/ or sparky general first>antigravity and/or overunity?Go away
I need some help. I have this 868Mhz garage door opener that I'd like to extend the range of by attaching a better antenna. I'm guessing one of these two thick traces is the antenna, but at which point should I solder on a connector?
Finished the board. Realized that all the traces have like a 87Mohm resistance between them. Guess there is a fine copper layer I cant see. Shame but it works for now for what I need till I can make another. Learned several things from this. Micro bit drilling sucks without a drill press. Need alignment pins if I'm doing two sides boards. Leave the thing in the acid bath for at least 30 minutes not 10. It was fun will make another when I have the right headers what I used was abysmal.
>>2546771What did you make anon?
>>2546771>Micro bit drilling sucks without a drill pressI had the exact opposite experience and was surprised that I didn't need a drill press.I used a rotary tool at the highest setting with pcb drill bits and it basically just aligned itself perfectly because of the copper traces.
>>2546781It's a test jig for through hole components for a nanovna or I guess any other VNA that uses sma connectors.>>2547055Well drilling 1mm here the holes I have to do next for my signal tracer requires 0.7mm but I just used some arbitrary micro drill bits I got from ace. Maybe there is a better type that might work or maybe the pcb material is difficult. It dulled any bit I used but they managed long enough to finish this job. Not entirely sure how I should continue. Need a signal tracer and I have the circuit laid out on kicad.
Help Identify Diode:Can someone help identify the correct diode in this circuit? It's glass so it looks like a germanium diode and has 35 printed in it. It tests as .38v when tested on the multimeter. Pic related is the part number on the service manual. Are all do-35 diodes the same? Could someone link to a similar part. Thanks
>>2547198thank you. if both are suitable what are the differences between them? I tried looking at the datasheets but im still a beginner
i want to build an electronic load using MOSFETs. the usual way is all analog with an op amp and a hardware control loop. i'm thinking about doing it digitally, with an MCU's onboard ADC and DAC feeding into a software PID loop. i might still need an op amp to step up the voltage (DAC is 3.3V) to scale with the FET's gate voltage requirements. my thoughts are that it's easier to tune PID coefficients in software than it is to desolder and resolder capacitors and resistors for hardware PID tuning.is this all reasonable or am i being a complete retard?
>>2547233do you think it would matter much that it has a higher reverse leakage current at 10V? it never sees that much voltage im pretty sure.Also why are some 1N60A diodes labeled schottky and others not? From what I understand Schottky diodes have different characteristics than standard germanium diodes and therefore calling them the both 1N60A diodes is confusing because they have different properties.
>>2547268Here. Read this thread:https://www.radiomuseum.org/forum/diodes_cross_referencing.htmltl;dr 1N60x is a suitable replacement for OA90 in your scenario (small signal RF).
>>2547272thats an awesome read. Thank you once again
>>2547282No problem, fren. Post updates if you get it going.
>>2546753I have a mechatronics engineering degree. I know what I want and how to do it. I have superior IQ. Still, should I mess with mains ?
When I was a kid, I touched leaded solder all the time without washing my hands, and inhaled solder fumes. Does this explain my brain damage?
>>2547298>mechatronics engineering degree>should I mess with mains ?
>>2547299You were so focused on the lead that you forgot about the 12 times you were dropped on your head. The drug abuse and alcoholism didn't help either. You didn't get the mRNA death shot too, did you?
>>2546768You might have better luck using a longer antenna on the garage door part instead. Especially moving the antenna somewhere away from metal shielding.>>2546771The impedance may just be flux residue, give it a good wash in IPA.Also couldn't you get those machined IC socket strips?>>2547241It's definitely possible to do digitally, you just have to ensure that it's fast enough. The PWM of any MCU will likely be more than fast enough, so what you need to care about is the ADC acquisition speed. There will be an intrinsic delay to care about, you may want to have an additional op-amp control loop.>desolder and resolder capacitors and resistors for hardware PID tuningEver heard of "potentiometers"? Digital ones, even.Also ensure you use MOSFETs rated for linear use. That or use cascaded BJTs, or make a switching load that buck-boosts the power into a fixed power resistor.>>2547298One hand behind the back and you'll be safe. Get some swanky elechicken gloves if you're a worrywart.
>>2547313I should have gotten that yes. I was just using what I had on hand I have extra material I'll make an improvement soon. Here's a 4MHz crystal I decided to measure.
>>2547341Ooh that's cool as. Are those crystals used as band-pass filters?
how does autocalibration of anything work? i understand calibration with an external device of a better resolution/accuracy, but how can a meter calibrate itself?
>>2547313>You might have better luck using a longer antenna on the garage door part instead. Especially moving the antenna somewhere away from metal shielding.Unfortunately I don't have access to the receiver. I'm thinking about putting an amplifier behind the antenna.
>>2547424>putting an amplifier behind the antenna.one way to get like 50% greater range is to put the transmitter under your chin pointing up.sounds crazy but has been verified by me in numerous scenarios.uses your head as an additional antenna.i just googled and it seems i'm not the only one to know this.search ''Using Your Head to Extend Your Car Remote Range - Altair''
>>2547313>There will be an intrinsic delay to care about, you may want to have an additional op-amp control loop.i assume you mean ADC sample and conversion delay + PID loop delay + PWM DAC output delay? what do you mean by "an additional op amp control loop"?
IT WORKS!!! finally gathered enough courage to remove and solder wires to the tiny connector pins on the thermal camera module, no serial config needed ether
>>2547473the subject is a DPS-465, lighting up like a charismas tree apon being plugged in heres an older pic of that
>>2547473>thermal camera moduleOy vey, you couldnt use your tongue like a normal mensch?
>>2547508lmao, atleast now im able to find shorted MLCC's without needing to dump a whole bottle of IPA on the board and see witch one dries off first
rate my project box
>>2547511Clock boy? Is it really you?
>>2547464PWM/DAC -> op-amp <- feedbackop-amp -> mosfetThe op-amp will keep it stable during transients, though depending on the power source being dumped into the load it may not be necessary.
>>2547419use some known physical constant that relates to whatever you need to calibrate against>meterwhat sort of meter? that could mean anything
Behold! and I witnessed a beast that like a titanic narwhal rise from the infinite black void beneath the roiling waters.Upon the face of the beast was a mark. And that mark was "Cython, wrath of Moros".
>>2547482>these things that let you change chips without solderingWhy did they even do that?
>>2547511Mains power with lose wires? Firehazard/10
>>2547550for example dmm. or adc inside it.
I soldered a 1Mom resistor and cleaned the board with 70% alcohol and a few minutes later measured it and it measured 200K. Then about 1 hour later it measured 1M as expected. I thought alcohol wasn't conductive??
>>2547602You should publish your findings in academic journals. Maybe they'll send you a Ph.D. in the mail and give you a cushy $200k+ job at some shithole university full of fags.
>>2547482>RaytheonThat's scaring me. Have you scavenged some sort of targeting computer?>>2547596I think they're often ROMs with firmware on them, so to upgrade the firmware you have to be able to swap out the chip. They often come with stickers, which you can read to figure out what version they are. Even if the memory (or memory inside something like a microcontroller) is erasable, in the early days this meant high-voltage programming. Having provisions for any sort of in-circuit-programming, let alone HV programming, increases board complexity. This added complexity is highly significant when it comes to gen-3 computing's parallel data and address lines.In addition, so long as the socket's connections can be relied on, it's also a way of making repairs easier at the expense of adding a few dollars to the board cost. For something expensive like computer hardware it's likely always worth it, at least back when clock speeds were in the MHz. Now-days the size constraints, both in terms of compact design and in terms of minimising trace length, and also in terms of BGA chips with far greater pin-counts, make socketing undesirable. May still find it on a bios chip or whatever.>>2547602It is conductive when it dissolves stuff. By letting the alcohol evaporate again it's just depositing the stuff back on the board, you want to scrub it off properly, or otherwise flush it out with multiple solvent washings. Some centrifugal flinging may get rid of solution in hard-to-reach areas.
>>2547610>conductive when it dissolves stuffmake sense. there is sticky gunk that doesn't completely come off no matter how hard i flush and scrub it with alcohol. it is one of those "no clean" fake kesters (the clear kind). > scrub it off properlyhard to do on a perfboard with a bunch of joints.>flush it out with multiple solvent washings.what kind of solvents? can i just flush it with water?
>>2547613Consider acetone, after seeing if it influences a spare socket header. Water isn't a bad idea, maybe vinegar/citric acid or something basic like dishwasher powder will work, but I suspect all the conductive nasties are trapped up in organic gunk, if not organic themselves.For scrubbing I use a toothbrush, and bang the thing on a table to splash out any remnant IPA. But an ultrasonic cleaner would work way better.
>>2547618a stiff toothbrush sounds like a good idea. i have a cleaning brush but it is too large and too soft. and it is approaching middle age (loses hair).
>>2547600you mean autoranging? thats different to autocalibration
>>2547610>That's scaring me. Have you scavenged some sort of targeting computer?yea i find those chips kinda strange too, its video equipment though, "video frame synchronizer", that also generates test patterns
>>2547512>>2547599>not knowing your electronics historyhttps://www.youtube.com/watch?v=vrZ_fMqd8k8
Is there an /ohm/-approved digital tabletop oscilloscope for around $500?
>>2547640no i mean self-calibration.
I want to play a 24/7 low volume forest soundscape in my living room - like this https://www.youtube.com/watch?v=xNN7iTA57jMWhat's the most energy efficient way to go about it?I have a raspberry 4 running 24/7 already, could drive it but probably not provide the power for the speakers. Any ideas?
>>2547828Also not sure I want them to use bluetooth. Already have enough of them beams around me, living in a flat.
>>2547404Crystal's are I think band pass filters in general. They usually only ring at the frequencies stated or some harmonic of it which people do abuse sometimes as well. But in the end they are just filters. Filters that have decent parameters and dont drift with temperature change. Now I was hoping to see the parallel reasonace but I didnt only the series resonance which is letting our signal through but I thought there was a parallel reasonace frequency as well.
You have no idea how often I forget to change the input when switching between voltage and current and resistance etc. I ended up using 3 DMMs each for more or less just a single function. So the idea of an all-in-one DMM sucks. I'd like to build a dedicated vmeter, microvmeter, and ammeter. And use M-Tester to measure RCL. Most people have multiple multimeters anyway. Each with 20 different overlapping functions. What a waste.
>>2547848You always need multiple meters no matter what. 2 at minimum. In case one breaks or you need to take multiple measurements at once or hell to verify that your meter is working properly.
>>2547827see original reply
What's the point of adding a 10Mom resistance to the DMM voltage input if most ADCs are buffered and provide at least 50-100 Mom of input resistance? Why can't voltage source be connected directly to the buffered ADC?
>>2547828>low volume forest soundscape in my living roomi got a few of these at the thrift store for $1-$5.
hi /ohm/i bought a japanese pachinko machine at a goodwill a few years back. i cant find a copywrite date on anything, but im pretty sure its from the 90s, maybe 80s. ive been using it as decoration, never really used it as intended. it sort of works; if i plug it in, i can get the balls to shoot, but none of the lights come on. i would really like to get it to light up, and ideally i would disconnect/bypass the motor so that it didnt make any noise at all when its lit up. im really just interested in the lights.in pic related, the metal box in the lower half is obviously the power supply. the weird thing above that looks like some solenoids that control a dancing guy on the front. to the left of that, under that rats nest of wires, is a board with a bunch of connectors. there might be some logic on the other side of the board, but im currently under the impression that the whole thing is entirely analog.feel free to ask for more pictures. ill post updates as im working on it. ideally, all of the lights plug into that board, and i can supply power to just that board. or maybe i could print a new board to replace it, and plug it into my computer to sync it with audio or some gay shit like that.for starters, any ideas how to test if a given wire goes to a light? from what i can tell, the lights are inaccessible from the front.
>>2547952I cant really tell but all the lights will be connected to the same system high up enough along the path. I assume this is all analog too which makes this a whole hell of a lot easier. Without a schematic I can only guess but if I were you try to find the most easily accessible wire that connects to a light and just follow the pack back to the power. It should be around the back somewhere. I'm assuming a wire rubbed through or a fuse is blown. It's probably something super simple.
>>2547952>from what i can tell, the lights are inaccessible from the front.it's 100% obvious you have to unscrew the assembly from the box to make any headway.but you're too afraid of ruining it.you know what? we're all afraid.but we get drunk and do it anyway.coz that's our mission as men: to dick around.All I do now is dick aroundWhen the sun goes up and the moon goes downWhen the leaves are green and the leaves are brown,All I do now is dick around.
>>2547952I'm not sure if this is right but the bottom right seems like a main power and I see it mounted to the side of the wood and it feeds up to that transparent plastic box in the top right corner. Might be some power distribution point but I cant tell for sure.
is easyeda okay? Is there a reason it isnt in the recommended tools section?
thanks for the replies>>2547968>if I were you try to find the most easily accessible wire that connects to a light and just follow the pack back to the powergonna be hard to do without knowing what any of these wires go to, but ill look around and see if i can spot something.>>2547970i like your poem!im not one to treat my projects with care, but its not like i can go buy another one of these. or at least i dont want to. also id like to wrap this up today so im not looking to disassemble the whole thing.>>2547971heres a close up of that box. kinda reminds me of fuses/breakers.
>>2547952>>2547991You need to check fuses, then probe for voltage (powered on) and continuity (powered off) in the relevant circuits. You might need to use contact cleaner on connectors, or reflow crappy solder joints. If you have a known-good bulb, install it in a non-working socket to test. Some lights won't come on unless you're in a certain scoring mode during gameplay.This is analogous to pinball machine repair, or jukebox repair. Check out Joe's Classic Video Games on jewtube if you're inclined.https://www.youtube.com/user/LyonsArcade/videos
i stand corrected, lights are decidedly accessible from the front. i think i found the connector for pic related, gonna unplug it and inject DC to see if they turn on. i have a breadboard power supply for 5v, might not be enough. i also have a 12v supply meant for blade servers (im the guy that made a foam cutter from a hair dryer last thread if you remember me).>>2548006thanks for the advice, i might look at those videos.
>>2547972it is great for a hobbyist. very easy to use and well integrated with LCSC and have a huge library included, no need to search for footprints. but some snobs may insist on using "proper" software. but kiCAD is pretty good too and also comes with everything included.
Somebody tell me a joke. I don't care if it's stupid.
Hey, I'm wondering if there is a charging chip, like this TP4056 , but that will be able to charge 3x rechargeable NiMH AA batteries linked in series to increase the voltage to 3.6v. I want to use this port as I can just plug a Micro USB connection in and charge the batteries, but the TP4056 is for lithium cells only I think?
>>2548010I'm not entirely sure 12v is going to cut it. I'm not experienced in these machines but I dont suspect they do much rectification or voltage dropping in stuff this old. It might need whatever line voltage is supposed to be applied to it but dont test that. Try the 5 if not step up. I'm only being overly cautious. If I could measure or clearly see how the power is getting around I could tell you for sure. The closest I could think in my experience is something like Christmas lights. The incandescent ones. 12v wouldnt work on that.
>>2548010You could just pop the bulbs out and see what the writing on them says
>>2548081Different anon, but I'm almost certain they're either 6.5V, 13V or 28V DC incandescent, like a pinball machine.
>>2548096I loft aloud. lmaoThanks, Anon. You're the best.
got some lights to turn on, now im just following wires and seeing whats wired where. then ill just connect a DC supply to all the lights and call it a day.>>2548081thanks for the advice. pic related is 5v maybe, cheap voltmeter is saying 8v but that cant be right unless the power supply is fucked somehow. i think they could be brighter.>>2548088theyre soldered on, and i dont think they have any writing on them.>>2548092thanks!
>>2547970Don't maintain essential machines when drunk,
>>2548096I didn't laugh. Also I as afraid of the gif changing to a second frame with a scare while reading all of it.
>>2548081>>2548092one dead bulb and a lot of broken glass later, can confirm its 28 volt, 3 watt. or at least that one was.
>>2548116Is there 28v getting to the places where the broken bulb.was? If it's not that voltage there may be other issues.
>>2548113>I didn't laughYeah, but you never laugh unless it's at someone's misfortune. Cynics are cool until they get jaded.
>>2548118im just trying to hardwire all the lights on. like that other anon said, under normal operation some lights wont come on until a certain state is reached. plus the motor is loud.
>>2548096i didn't laugh. whoever wrote it could probably get hired as head writer on SNL.
>>2548071a man goes to the doctor for a physical. the doctor says "sir youre going to have to stop masturbating." the man asks "why?" the doctor replies "because im trying to give you a physical."
>>2548096I laughed. Then I laughed again at the people who didn't laugh. I must be getting old.
>>2548071When Prometheus first laid eyes on fire, was it a match made in heaven?>>2548075Technically you need balancing for series cells, though you can probably ignore it if the cells are well-matched, since NiMH cells are pretty tolerant of overcharging. Or buy a NiMH 3S BMS. The rest is just CC+CV, probably with a cutoff threshold that triggers when the current is low enough. There may well be ICs designed for this, otherwise using some RRIO op-amps and some sort of comparator latch will do the trick with a few dozen passives and a pass-transistor.
>>2548132>When Prometheus first laid eyes on fire, was it a match made in heaven?I'm going to put on my carbon monoxide gas mask now. Goodnight.
planning on getting this crimperhttps://www.amazon.ca/gp/product/B01N1RFZZ4I assume that I could buy replacement bits for more crimping options, like this one:https://www.aliexpress.com/item/1005004693837419.htmlI could buy the cinlin on ali over the iwiss, but they are the same price.I plan on crimping these (I use the digi part number):A107109CT-ND (quick connect male 0.187)A116211CT-ND (quick connect female 0.187)A123074CT-ND (quick connect male 0.110) A131017CT-ND (quick connect female 0.110)A26962-ND (dupont plastic housing)A25993-ND (dupont female)A33420-ND (dupont male)I am open to superior alternatives, the connector doesn't really matter, I just need a high amp connector with 15a max, and a medium amp connector with 1-5a, and a low amp connector. I probably should use a polarity protected 2 pin connector, but these are for internal connections that will heat shrinked after I am done.unrelated but I will also buy a stripper Capri Tools CP20010, it's $10 cheaper than the klein tools original.I have 16awg wire, I will try to strip it to 18awg, it has 3.0mm of outer diameter.I think have 22 wire (I actually don't know, it has 6 strands and I think it's like 0.8mm diameter when twisted neatly, and all the text on the wire didn't give any results on google), and 2mm diameter (from manually measuring).>inb4 leafThanks if you actually go through the datasheet to make sure I didn't make a fatal mistake.I probably could just buy a crimp set that comes with the crimper, but I really don't need that many crimps.
is there some official certification or training course for learning how to microsolder?
>>2548212I understand why you would need to, if you repaired stuff, but why micro solder when a machine will do it for you for $3 per reel?
gonna call it here. theres a few more lights that i never got to but i dont think theyll make a huge difference. thanks for the help, all.
I want to start out with doing basic electronics repairs. There's a chinkshit dollar store at the mall that sells a soldering iron and multimeter for like $10 each. Will that suffice? I figure you can't really fuck up a soldering iron, but maybe I should get a higher quality multimeter?
Alright guys, I acknowledge that I'm retarded.While rewiring my basement, I fucked up one particular spot and can't get it to work any longer no matter what combination I try. The circuit did work and I haven't moved anything around other than the wire connections.Assuming black is power and brown is neutral and ignoring ground because I haven't touched those wires at all (or the two red wires either), how can I get this setup to work assuming either switch will power both lights?Reminder that this setup did work a couple hours ago.
wait i thought brown was live and black was neutral
>>2548237if you want to go as cheap as physically possible (while also buying some cool batteries), I would go and buy the $5 iron and $3 meter here.https://batteryhookup.com/collections/accessoriesNote the batteries could be used/recycled (if it doesn't say "NEW"), so you could get a good batch or a bad batch.Learning about batteries, how to charge them, and etc is really complicated, a lot to learn, but it's fun.Maybe you can make a DIY portable usb charger, or if you buy high current batteries, you could build your own spot welder if you buy the DIY board (it needs like 100-200a of current at 12v, like a car battery), but note that cheap spot welders do exist, so don't spend too much on it.Generally speaking Li-Ion batteries can combust in flames and turn into rockets that fly hundreds of meters away, Lifepo4 are heavier and lower capacity and more expensive, but super safe (and run at a different voltage).https://hackaday.com/2022/10/10/lithium-ion-battery-circuitry-is-simple/If you want something higher quality, I suggest Aneng AN8009, or AN870 (whatever you find cheaper, but AN870 is better because it has 4 ports over 3. and the AN8009 have a uncommon probe connector, but it's fine). Also they probably don't come with batteries.The main advantage over the $4 meter is that you have auto-ranging, thermo-couple, better ranges, and optionally a bag and accessories, and you can measure AC.https://www.youtube.com/watch?v=xdGQEVdxmQQThose meters could already be pretty expensive for you, and personally one of the things that annoys me is that I don't have an oscilliscope, which be really useful if I made a buck converter or worked with signals, so if you keep the cheap-o meter, maybe instead invest in this decent oscilliscope:FNIRSI-1C15link herehttps://www.aliexpress.com/item/1005004082468752.html
>>2548258Ehh don't worry too much about my color choices. All I know is if I put that black power line to a lightbulb it goes on
>>2548260oh yea, there are also used oscilloscopes, you might grab a 20mhz one with digital storage for $20 would be a steal.
>>2548071EEs never die. They exponentially decay in the time domain.
>>2548128was doctor a qt?
>>2548239>how can I get this setup to work assuming either switch will power both lights?you have the wrong switches. you need 3-way switches.they have 3 terminals on them.
>>2548260>>2548276Very good info. Thanks frend
>>2548298also note that you should hold off from buying until you know exactly what you need the tools for, maybe plan more than one project if you are spending a large amount.the oscilloscope or multimeter for example might not have the range for the voltage / current / ohm's / etc that you need.I could also list other meters, alot of them can be really good, and for the AN8009, there are many multimeters that use the exact same chip (the an870 has it, kaiweets km601 has it, if it has 9999 counts, it probably has it) so you pretty much get the same experience (but when you go cheap, there are always some sort of cut corner, or the meter is just more expensive).technically a 6000 count meter would be more useful than a 2000 count one if it has auto-ranging, and that could be just a cheap upgrade.But beware, some multimeters and oscilloscopes are designed for different purposes, some are automotive, which means the ranges are way higher than you need for hobby electronics, and learn the specs, watch video reviews, compare diligently.Also if you want to learn solar power, you might want to get a clamping meter, because to measure current, you may need to cut the wire just to measure the current (but some are AC or DC only).
>applied science finally made a video on diy nmr spectroscopyhahahahaYES
>>2548288I had a chuckle mate.
/ohm/ is where the hard is.
>>2548237You absolutely can fuck up a soldering iron. Don't get me wrong, it will heat up, but an el-cheapo iron will be unregulated, and the temperature will be all over the place, likely way too high. If you pair this with a shitty solder, you will frustrate yourself to madness to solder anything, and the soldering will be shit regardless.
>>2548506Why I bought my hakko was tired of the radio shack nonsense. Tips die within a few uses and yeah temps either too hot or too cold. Ripped traces with that shit. Used the hakko all those problems stopped.
>>2546753What multimeter should I buy? I am look at https://www.aliexpress.com/store/group/Multimeters/3095007_511960364.html?spm=a2g0o.store_pc_groupList.8148362.6.358136f24udCp3&origin=n&SortType=orders_desc&g=y and I am interested in UT139C. Is the UT61D(+) worth the 10 dollars more?
>>2548565It depends on intended use. If you intend to do any kind of poking in distribution boxes you need to look at proper CAT III meters, because you just can't trust chinks with safety ratings. For electronics pretty much everything is fine so pick based on features/precision.
>Maxon OD808 overdrive pedal I bought from a friend years ago for 20 euros or similar, he also bought it for 20e from another guy.>Never really used it, decide to try it again>Still just underwhelming (obviously my playing is shit too but that's beside the point)Opened it up to see if there is something obviously wrong like caked vomit everywhere but no, everything seems fine. I'll pass this joker on by offering it for 10e and a beer to someone and they'll think it's a bargain.
>>2548132 >>2548075can you explain a bit more simple terms for me, I have researched some of the components you listed here but how would I know how to put it together, or is there any resource you could point to that could help me
So, i am upgrading an ups to use external batteries instead of the shitty internal, as i had 3 laying around. Which connector would you recommend to connect the batteries instead of having wires through the holes or whatever? i am in the eu if that matters.I am also using a 60v to 13.8v dc dc to connect my ebike battery to it, now it just werks as a generator
>>2548613Quick disconnect terminals (aka fast-on/slip-on) are the standard for UPS batteries. You could probably get away with XT90 connectors if you really wanted.
>>2548613>now it just werks as a generatorinverter, not generator
>>2548630>>now it just werks as a generator>inverter, not generatorYes, of course, my point is that i can use it instead of needing to borrow a gas generator if I want to use some light electric tools, and floor lights, etc.>>2548622>Quick disconnect terminals (aka fast-on/slip-on) are the standard for UPS batteries. You could probably get away with XT90 connectors if you really wanted.The good ones are bulky, and there is very little space on the ups, as there is the dc dc circuit and wires, instead of the battery.Now that i think, I could put them in sae connectors so it uses the same connector as my ice bike, but I cannot find them as standalone connectors hmm. Maybe xt connectors are the best option. Thanks
>>2548636Maybe a heavy-duty terminal block secured in the UPS battery compartment, with thick gauge wire crimped with ferrules on one end, and the battery connectors on the other.
>>2548565in my opinion, you could get a UT139E because it has the bar display.But I can't say that this meter has amazing bang per buck compared to aneng AN8009 and AN870 meters, or kaiweets KM601, or if you don't mind the slightly poor range, you could get a Kaiweets ST600X, if it's really cheap for you. (one red flag is that it can't read milivolts range in DC, you can still measure 100 milivolts AKA 0.1 volts, but you can't measure 100 microvolts, but I think someone with more experience could tell you whether or not that matters, because the ST600X combines DC and AC into one mode, so maybe the reason DC doesn't have milivolts is because of noise or something).
Ok guys i need help. I dont know if am very retarded or something, but i just dont understand voltage, resistance and current. I know how they relate and i have build quite a bit of curcuits, but i dont have any intuitive idea of what they actually are. Am i too retarded to pick up this hobby, or do i just need a good explanation?
>>2548608A BMS is there to prevent one or more of:>cell imbalance>overvoltage>undervoltage>overcurrentArguably you don't need all of those, but I'd want undervoltage protection and probably cell balancing. The charger itself should prevent overvoltage, while overcurrent is up to your load to prevent. If your load has an MCU+ADC in it anyhow you could use it to monitor total cell voltage for undervoltage cutoff.A charger IC like the DS2715 will charge from 1 to 10 NiMH cells in series, though there's plenty of other similar ones out there.
>>2548665I just watched people repair shit.https://www.youtube.com/watch?v=O0EQFxA6lNgI also watched some phone repair stuff but i forgot the names. eevblog videos aren't bad. and some videos on diy project videos too, like from GreatScott.But I am not a professional, I am probably never going to repair anything LOL.
i'm trying to add a preamp to a USB micIt works great when i power it with a 9v battery however when i power it from the USB it picks up allot of noisewhat am i doing wrong?
>>2548665>i just dont understand voltage, resistance and current.google ''dc circuit water analogy'' and all we become clear.(assuming you know how water works)
>>2548665Try the first ~15 pages of "Getting Started in Electronics" by Forest M. Mimshttps://archive.org/details/gettingstartedin00mimsAlso, a lot of times courses try to introduce the concepts of voltage, current, and resistance as though they are separarate and discrete phenomena.... These things are interrelated properties of electricity. Voltage is best understood as it's other name: electromotive force.
>>2548678EMIa 9 volt battery doesn't have a ripple, but a 5v usb charger uses a switching power supply which is efficient, but when you look at the signal in the scope, you will see a square wave instead of a flat line.my microphone mixer uses a 120v AC to 5v250ma AC linear supply, which is just transformer which is just 2 unconnected strands of wire wound up around a piece of metal, less wire on one side means less voltage (at least I think that's how it works).
>>2548678The BM800 already has a preamp, but it needs a higher voltage to actually work. You should use it with phantom power from an audio interface. That or design a better mic.
>>2548678Try this:https://audiouniversityonline.com/twisted-pairs/Ferrite clamps help too, but you need to know the noise frequency range so you can pick the right filter.
>>2548666ok and this charger IC DS2715, can I buy it pre installed with a usb-c or Micro USB style port that I can plug a wire into. I want to embed the batteries in a box so I don't have to remove them and charge them externally, I can just plug in like iphone.
>>2548293I haven't changed the switches from when the setup worked. Every single cable has a black wire, white wire, and copper wire. The switches also have a red wire. I removed the copper wires from the diagram because I never touched those and they are all combined at one point, and I used brown to represent the white wires. The red wires are connected as the diagram shows and I have not touched them either.
>>2548706>Ferrite clampshuh. that reminds me, i have an old treadmill, that produces some electric interference when is being used, would ferrite clamps work on that? or are they only useful on dc
>>2548753It's probably common-mode noise which is normally filtered by a choke and Y capacitor. Make sure your ground path is solid and low impedance.This guy had the same problem:https://sites.google.com/site/treadmillrfi/
>>2548726not anon, but you could just buy a lithium polymer battery that fits into the AA enclosure and use that, because 3 AA batteries max out at 4.5v, and single 3.6v li-ion cell max out at 4.2v.I would suggest buying from here if you are from the US, but this is the only cell offered, and it's a bit large 50mm x 80cm.Note this battery is 3.8v (to reach this, you need to charge at 4.35v), but it works fine if you use it with a 4.2v charger, and it comes with a protection circuit, so you don't need to worry about killing the battery with low voltages, but make sure your recharger has trickle charging so when the undervoltage triggers, it can revive the battery (it's likely this will happen because the BMS under-discharge is 2.8v but the TP4056 should be at 2.9v, so if the battery self-discharges over time, it could fall below 2.8v, which means the recharger will not detect the battery). Also this battery's BMS is limited to 1a of current.https://batteryhookup.com/products/new-3-8v-4500mah-17-1wh-lithium-ion-battery-w-pcb-73-kwhIf you are buying a TP4056, you don't need the DW01 chip, because it's already on the battery, but if you plan on using your device while it's charged, you should use a mosfet + diode circuit to prevent the charger from overcharging the battery, it won't kill the battery, but it will use the life of the battery when it could be using the usb 5v input directly, and let the battery cool.https://www.best-microcontroller-projects.com/tp4056-page2.html
other than looking at frequency response and spl, how the FUCK do you select SMD speakers for a project? no matter what i google i get absurd audiophile bullshit. i'm going to make a little circuit to plug into a usb wall wart that plays rain sounds while i sleep, so the fidelity doesn't need to be great.
>>2548777I've seen people use phone speakers for stuff.they aren't surface mountthey can be really loud though.unless you are looking for a buzzer.
>>2548753Assuming it's a brushed motor, I'd put the clamps, if not full-on chokes, in series with the motor windings. And put X2 caps directly across the motor too.
>packet of tl431s>each one says "431" on it>test with diode checks>they're tl432s
>>2548813>Anon figured out that Chinks ruined the electronic hobby with their fake garbageyou lucky, i spent 30 bucks on op amps and all of them were fakethose bastards even make fake transistors and capacitorsif you want genuine parts your only option is to buy them form digikey, Farnell, Mouser or Conradits gonna cost more but at least you are likely to get real stuff
>>2548466hey at least they used Rubycon!
>>2548466Hello Dear, you claim we scam. How we scam when we give better capactor?This dispute has been closed by aliexpress
>>2548665ill give it a go.imagine a ball at rest at the top of a hill. the ball then starts to roll down the hill at pick up more and more speed as it goes. eventually it reaches the bottom of the hill, and this will be the balls top speed. you might be tempted to say that the ball started its journey with zero energy (since it was at rest), and reached the bottom with a lot of energy. this is okay, but in physics we like to conserve energy to make calculations easier. so instead, we usually say that the ball started with a bunch of "potential energy", and we might say that specifically it was "gravitational potential energy", and as the ball rolled down the hill more and more of this potential energy was converted in kinetic energy. when the ball reaches the bottom of the hill, it will have lost an amount of potential energy exactly equal to its kinetic energy (assuming it didnt lose energy through other means, like friction).if you replace "gravity" and "ball" in this analogy with "electricity" and "charge", then you would end up with "electrical potential", which is a fancy term for voltage. although we dont say that charges have electric potential, we say that regions of space have electric potential. for example, if the bottom of a AA battery is at 0 volts, then the top is at 1.5 volts. the unit "volt" is equivalent to "joules per couloumb" (which are units for energy and charge, if you didnt know). so if you had a 1 couloumb charge and moved it from the top of a AA battery to the bottom, it would gain 1.5 joules of energy, probably in the form of speed. its important to note that voltage is all relative; if you stack two AA batteries on top of each other, the top of the upper one will be at 3 volts even though the field inside didnt actually change. its like if you stacked two ladders on top of each other to get twice as high.ill continue if someone wants.
>>2548742>The red wires are connected as the diagram shows and I have not touched them either.why are you still posting? it's time for action.if indeed your switches have 3 terminals, just disconnect everything, re-wire it exactly like the drawing and it'll work 100% guaranteed.the color of the wires is irrelevant, just follow the wiring diagram exactly. the switch terminal with a black circle is called the ''common'', and it'll be marked in some special way.the other two 2 terminals (travelers) are interchangeable.even if you screw up the wiring of the switches, nothing bad will happen, coz the lamp will always be in series with the circuit, through the neutral, so no explosions.
ok so turns out lm358s aren't a good selection for a milliohm-meter instrumentation amplifier, even with a total gain of 1. i guess i should go for cmos op-amps with their low input offset voltage
Want to replace this capacitor. Service manual says 10,000 pF 700V but first search came up empty, and 700V seems excessive for a motor capacitor for a record player working on 110V line voltage.
>>2548952Might be a class-Y capacitor, in which case excessive voltage rating makes sense since they're designed with grounding safety in mind. Replacing it with any modern 10nF class-Y cap should be fine in that case.
>>2546753my browser keeps telling me the lipo battery required reading in the thread pasta is a virus.
>>2548983It didn't do that before. I think they just let their license expire.
>>2548846thank you, but i think i am just retarded
>>2548590I have a theory that guitar needs to be split into low frequencies and high frequencies to sound good with distortion. Only the high freqs should be distorted, the low freqs left clean (cutoff ~100Hz), then everything re-mixed back together.
>>2548394Hallelujah, I no longer need to feel like the only person on earth working on this kind of project
what would be the best kind of sensor to detect a hit from a high speed bullet on a plastic target? i've been looking at vibration sensors, but i'm asking here if anyone has better ideas. basically what i want to build is like the type of automatic popup targets used on army qualification ranges, but i want an mcu hooked up to it and a radio to transmit hit detection up to 1km or more, probably using LoRa.
Guy who made that VNA test jig here. >>2546266Hey I have this as well only second edition though. It is a nice gift that someone gave to me.>>2548590I'd take that offer. Though you would be paying for any component replacement. Seems simple enough to dick around with and get going. So that beer would be a steal.
>>2548983It's just a bad SSL cert. They're the least danger security "threat", but every browser warns against it in an extremely verbose way, while not even stopping worse security threats by default.
>>2548952>>2548973On second thought I'm a little confused. I was hoping the capacitor was there to even out line voltage for more consistent speeds but I don't know why it would be placed in parallel with the switch like this seems to be. And I'm pretty uneducated about electronics so I know I might be using the wrong terms. A quick google search suggests it's there to prevent arcing when the power disappears. How come the capacitor doesn't just bypass the switch? It reads as open in-circuit. Is it supposed to do that or is that a failure state?
>>2549234I think it reduces the 'pop' sound when it's switched on.>s it supposed to do that or is that a failure state?Capacitors are two pieces of metal that are separated by a dielectric. They aren't supposed to make contact.
>>2549248Thanks! Won't bother replacing it then, as it seems to work just fine. Seems like it's time to lube the motor.
>>2549250You're welcome, Anon. What's the first record you'll play on it?
>>2549259Picked up some grungy old thing called Cafe Continental at goodwill the other day because I had nothing to test on it. Already played it once or twice since the TT already works, with some caveats.
>>2549281This one?https://folkways.si.edu/ruth-welcome-and-dick-marta/cafe-continental/world/music/album/smithsonianbreddy gud
>>2549297This one https://www.discogs.com/release/8797572-Les-Cinq-Modernes-Romantic-Moods-Of-Rome-And-Paris-Cafe-Continental
>>2549305It's like I'm taking the elevator to the penthouse suite in Caesars Palace, 1966.>Doobie doo zop skibbety skoobop Zatarain'sPerfect for testing the tonal quality of your setup.
>>2547602What is the other 30%?
i think there's an impostor...
>>2549314he is using hand sanitizer rubbing alcohol, the rest is water.it's not recommended for circuit boards because water is corrosive, but it doesn't really matter if you just wipe it off, and wait an extra couple hours before turning on the electronic.
I want to play SimCircuit on the SNES.
>>2549309It's definitely intended as a demonstration record, but it's a bit beat up because no paper sleeve and the outer jacket is beat to hell. Dramatic channel separation and a wide range of instruments with no vocals. I'm stalling getting into the hobby because I'm broke as fuck anyway, so everything is as cheap as possible. Still wouldn't mind putting a record I actually value on it at the moment. I don't even have a plinth for this thing yet, I've been putting off buying a bit of wood and a cheapo router because I'm such a miser.
>>2548845ali customer service be likehttps://www.youtube.com/watch?v=x6HE2kdj6Zc
Can anyone recommend me a voltage reference? I've decided the TL431 isn't a very good fit for a lot of what I do. I'm after a low-drift jellybean part, doesn't need to be a high-current multirole shunt regulator like the 431, but something at least half as ubiquitous.
>>2549372If you want to see what's ubiquitous, go to the voltage references section on digikey, filter by what's in stock, and sort by stock descending.431 and 432 dominateLM4040 is reasonably popular
>>2549372What are you criteria? Accuracy, tempco? Price range? What are you planning to do with them?Here are my notes when I was comparing various references:REF5020AI: 8 ppm, 0.1% REF5020I: 3 ppm, 0.05% AZ431-A : 20 ppm 0.4% 4.5mV T deviationLTC6655 noise: 0.25ppm p-p, temp drift: 2ppm or 5ppm, 0.025% or 0.05% LT1021 : 5 7 10V noise: 1ppm, 5v: 3uVpp noiseLT1021-5: C: 0.05% td: 20 ppm B: 1% 5ppm D : 1% 20ppm1 ppm : 1uV for 1VAD584LM399ADR45xxADR4540 4.096v Some of them are quite expensive.
>>2549099Besides pots and the foot switch the most expensive component is the JRC4558D Japanese opamp folded over thousands of times and differential hardened at <1e so no problem.
man this is a good looking gate driver:>https://datasheet.octopart.com/NCD57252DWR2G-ON-Semiconductor-datasheet-150738170.pdf
beware the chimeric op-amp
>>2549250You should double check that what does the capacitor look like? If its pne of the old paper and wax ones it might be a good idea to replace it. Might not matter too much in this circuit bit these things can fail and take stuff out with them.
>>2549339>I'm broke as fuck anyway, so everything is as cheap as possible.Are you me? Being broke gives you the excuse for being creative with your solutions. Maybe the plinth could be made of cement, or epoxy and sand with a thin wooden veneer around the exterior. At least as a temporary solution, until you can source better materials.>>2549608Anon posted a pic >>2548952It's not electrolytic.
I've got an old walk behind tractor. The engine from it has 15HP and maximum RPM of 3500. I want to make a generator out of it by putting a belt between the shaft and an alternator.How to figure out what alternator will be most efficient for this engine?
so my digikey order had 2 problems, the blade fuse holders were too small, and I got a very tiny banana plug.I guess I will manually solder the fuse contacts, and I wanted the banana plug because I wanted to make my own multimeter alligator clips that have a flat contact, so you can connect it to nickel tabs.
>>2549797I've done the same thing, Anon. Live & learn.
>>2549797Was there something wrong with the order, or does it conform to the specs and they just weren't what you expected?
every knob I've ever ordered was defective unless I spent at least $1.50 on it
>another one falls for the mini banana jape
Hello. I'm trying to step up into Kicad. I loaded the library, OpAmp wanted is not present.I downloaded what promised to be a good 3rd party lib from Github, OpAmp's ref is still not into.>https://github.com/PatrickBaus/KiCad-libraries.gitDigged a bit more.. Library format is too old..>https://github.com/kicad-spice-library/KiCad-Spice-Library.gitI think I could just select a generic model ?or is there a good LT library to downtoad ?thanks for tip
Are these just photodiodes? I dont see gates.These are from a dvd pickup but theres two different type for some reason...
is there something like a reed switch that stays isn't momentary on? something where you can use a magnet to flip a switch between two positions. the problem is i want a switch inside a plastic container that isn't visible from the outside. i could probably do a radio receiver, but that seems like overkill when all i really want is a simple passive switch that can be controlled through a thin sheet of rigid plastic.
>>2549880There are normally open and normally closed options. NC is opened by a magnet, NO is closed by a magnet.
>>2549872Are you wanting to simulate, or just lay out a schematic? If it's just for the schematic I'd pick any old op-amp with the same pinout and footprint, save its symbol under a different name, and edit the details like datasheet and tags appropriately. You can also just import the wrong op-amp into your schematic and rename it there.>>2549880Maybe this will work:https://youtu.be/D19AnjZnEFAAssuming you want non-volatile memory. The more professional method is to have a shitty little microcontroller with EEPROM to save the value during turnoff, but it's less fun.Using a 74LVC1G73 works if you're fine with volatile memory.Taping some alfoil to the inside of the plastic sheet and making a capacitive button out of it works also, with the same volatile/non-volatile question to be had.>>2549888He wants a latching button.
>>2549889>He wants a latching button.and I want a UFO so I can harass governments all over the world.
>>2549884Where are the gates then?
So i have a ton of stationary bateries which are not in the best health status. Sulfurated or whatever that is called in englesh.Do anyone know how to make a pulse charger that can regenerate them? if a 15€ lidl charger can do it to a small extent, it cannot be that difficult to do.The problem with the lidl one is that it only want to start working in certain situations which are not that helpful for old batteries.
can you guys recommend me some test leads that have friction fit ends so i can attach alligator clips and backprobes not the fluke/pomona ones, not paying $50 for leads give me a break
Here is a board I am putting together for a signal tracer. Is this okay? I am pretty new to this stuff.
>>2549909You can build this one for about 5€ - Cheaper if you already have some of the partshttps://youtu.be/i_yFhI1JRDM
>>2549889that's not exactly what i'm looking for. the wording might have been confusing, but i want a simple double throw electromechanical switch (ON-ON) that can be operated through a sheet of plastic, say 1mm. ideally, it wouldn't be powered at all, so the question of volatile memory or not wouldn't really apply. a capacitive button or reed switches would work for a powered circuit, but i think i might try and cobble together a switch myself. i could stick a magnetic material at the end of an existing slide or rocker switch, or try and cobble together my own switch with a conductive, magnetic material on the inside to bridge the contacts which can be manipulated from the outside. i was just wondering if such a thing already existed.
>>2549927>Is this okay?not okay.you need to make a sound, not light an LED.looking away from the test point to your LED will slow you down a lot.and your grip may slip and cause a short circuit.>>2549965>ideally, it wouldn't be powered at allif you can use the god-like power of tilt, you can use a mercury switch (or mercury-whetted reed switch or mercury-whetted reed relay.)only a few degrees should be enough if you place it correctly.
>>2549927Post schematic>>2549965>double throwYou could connect an NO and NC reed switch together, though I wouldn't do that if make/break order is important.Does it need to be momentary or latching? What does it switch?It could be doable to have a knob magnetically stick (with both centre and ring magnet) to the front of the plastic, and turning the knob would pass a perimeter magnet or two over a reed switch or two behind it. That way you don't break the plastic layer, and can have it be latching quite easily. You could ensure break-before-make using magnet size if you know what you're doing. Even add detents. I've often thought about using this to interface with a custom shower's digital temperature control.
Nobody told me that there are 23 new Buffcoat and Beaver episodes. Why didn't you tell me, /ohm/bres?
>>2549973tilting wouldn't be preferable here, but cool>>2549980using an NO and NC reed switch pair in parallel would require that a magnet be kept next to the plastic to change positions. i'd prefer it be latching, and break before make. i'd also prefer if the magnet wasn't present except to switch it. it would switch component video signals. your perimeter magnet idea is interesting, but i think it would be easier to just use contacts and a wiper. i drew up pic related for how it could work using a rotary design. like a rotary switch but without detents to make it easier to manipulate with a magnet.
>>2550026You can just remove the detent spring/ball from inside a rotary switch.>it would switch component video signalsYou may find you have capacitance crosstalk issues, real systems are more likely to use RF switching diodes or transistors, but give a standard switch a try to see what it's like.
>>2549973It will make a sound. I have a audio box for it with a speaker. It will be using a 3.5mm jack to feed to audio out. This board will be in a hand held case with all metal components covered.
>>2550030Why not put a little piezo on the board itself?
I'm making a project that runs a microcontroller, a camera, and a stepper motor to run underwater for at least an hour. Any ideas for what kind of battery I should look out for?I wanted an nimh one so it doesn't explode if my housing fails but I'll settle for lipo if that's what I need for the capacity and power.standard nema17 motor, takes about 2.5 A current and the controller board is a HAT run with 8-24 V
>>2550051Depends on how much power the stepper is exerting. Those steppers do take a constant current when stalled, which you could assume for a worst case scenario, but you could reduce the stall-current by PWMing its windings if you don't need the full stall torque when not using. PWMing it to reduce torque when stepping is also an option. With proper driving algorithm that measures back-emf to sense skipped steps (may need an encoder instead) you could keep position accurate while dynamically modulating current consumption. If you don't need precise positional setting then use a BLDC instead.That motor stall current will depend on the voltage you use, and will be I=2*V/R, where R is the resistance of one winding. Camera and everything else will likely draw only a fraction of the motor, so use it +~10% for safety anyhow.A sample calculation:Assuming the motor runs at 2.5A, 24V, for the full hour, that's 2.5*24=60W, 60*1=60Wh. Assuming you use 18650s (less dangerous than lipos) each one stores ~3.7V*3Ah = 11Wh, so 6 in series would give you the right energy content AND approximately the right voltage. Assuming your driver can handle as high as 25.2V. You can get 18650s smaller and larger than 2.7Ah, rated for different amounts of current draw, though 2.5A should be pretty doable for most.
>87c each for a chinese TO-220 MOSFET rated at 208Ado i risk it
>>2550031Because I have a nice little permanent magnet speaker that I want to use with this and it wont fit. It is a nice speaker using it on my breadboard prototype and I can pick up a radio station with it. Pretty rad.
>>2549889>just lay out a schematic?mostly just lay out a schematic yes.I then though yes I will not be able to simulatebut since my goal is just to order a PCB, it's drawing a schematic yes. I'll learn simulation with something else.
Hey guys I'm looking to make battery powered RF temperature loggers for a buddy who does HVAC work. I want the sensor nodes to be as inexpensive as possible and last as long as possible on a single battery change. Radio range is irrelevant since the gateway is going to be in the same room.I'm thinking of going with STM32G0 MCUs, a simple amplifier with a couple of ranges to measure 1% 10k NTC and nRF24L01+ radio modules. 400mAh li-ion cells for power (or does 2S AAA cells sound better?)Does that sound reasonable or should I go with anything different?
Hey guys, I'd like to be able to control pic related with a microcontroller, be able to select which resistor to use for autoranging. I have a current source which I want to measure. The current source can go from low to large currents and when the current is too low, it drops below the adc resolution. So I'd like to be able to switch sensing resistors when that happens automatically. I was thinking of using a transistor to do it, but I think it can cause issues with AC signals since the input is a large signal that can change the biasing of the transistor significantly. Anyone knows how I can accomplish this? Bonus point if your solution allows for more than 2 resistors (like 3-4 resistors). I have a limited amount of ADC channels so using one adc channel per level is not good, I need to be able to measure it all from one adc input.
has anyone used wet slug tantalum capacitors? i wanted to buy a dozen 100,000 uf to experiment with them in a linear power supply.
>>2550282What sorts of currents are you working with? The most obvious solution is to just use a spdt relay. Standard BJT won't work because they're not made symmetrically, realistically only JFETs could work, but the issue is they have anywhere from 50 to 200 ohm on resistance. If currents are small you can use analog switch ICs or multiplexers, but those aren't made to handle any significant current (20-30 mA max.).
>>2550341It's used to read a current transformer secondary, so it's unknown yet (depends on the transformer), but I don't expect the secondary current to be more than 50mA if using a 1:1000 or 15mA using a 1:3500
Would it be difficult to build a miniature solar charge controller with pic related, PCF8591 & 12 V/200mA solar panel? How should I get started? Ideally I'd like to use it for charging 2 or 4 AA NiMH batteries.
>>2550342It's probably best to stick to mechanical relays, analog switches that can handle 50 mA are quite pricey. Alternative arrangement would be to instead use high value resistor to get large voltage drop across it and then use divider + analog multiplexer IC, like pic related.
>>2550343Yeah should be doable. Not trivial though, especially cramming it all into 2kB flash and 128B ram.Any reason to go for a combined ADC/DAC instead of just an ADC? Though you could use that DAC as a variable reference for an external switching IC, like a TL494. Charge balancing (if you want to bother with it) will require as many analogue inputs as you have cells, so it wouldn't be possible to do both MPPT and balancing at once.Also there's basically no reason to go for such an antiquated MCU, but hey I've got some AT90S2313s myself. Because they were under 50c each.
Why do i see a diode in some diagrams connecting a DC fan to an arduino via a transistor?
>>2550473Because fans are inductive loads, inductors store energy as a function of current. When you turn them off suddenly, that energy has to go somewhere, and it tries to keep current going in the same direction. Without what's called a "freewheel diode", this results in a large negative voltage spike that breaks the transistor. With the diode, this current just circulates inside the motor and the diode, dissipating itself. The same thing is done for relay and solenoid-valve coils.
>>2550479Thanks for the walkthrough, aren't you talking about the diode that usually goes in parallel with a relay? What i'm seing is the diode in series with the fan.
>>2550484>What i'm seing is the diode in series with the fanWhat I'm seeing is you not properly describing what you were talking about in the first place. I've never seen such a circuit myself. Post a pic maybe.
>>2550533nevermind, i got it, i just don't get the science behind the inductor inverting the polarity, anything i can read on this?
>>2550282I was curious about that at some point too, and it appears to me that a mechanical relay is the way to go. That's the way it is done in oscilloscopes and bench meters. However handheld DMM doesn't have any relays. Nor do they have any kind of electronic multiplexers. Yet the can autorange from uA to A. Perhaps they use multiple ADC inputs built into the micro chip hidden under the epoxy blob.
>>2550550If current is flowing from top to bottom when energy is going into the inductor, then the top is going to be more positive than the bottom. But once no more energy is going into it but rather trying to come out again, with the current flowing the same way (an inductor resists changes in current) you'll find the voltage invert to keep current flowing in the same direction.May be more useful to consider the AC case, where you feed a sinusoidal voltage to an inductive load, and derive that it absorbs energy during one quarter cycle before emitting energy during the next quarter cycle. See:>V = L*dI/dt>>2550551I thought they just used one current shunt per range-switch mode (eg different A, mA, and maybe µA) and just a programmable gain amplifier after a fixed sense resistor.
>>2550550When a charge is applied to an inductor, a magnetic field surrounds the coil. At the moment the charge is removed, the magnetic field collapses which gives rise to a voltage spike of the opposite polarity.
>>2550560>programmable gain amplifierAh you are right, forgot about that. I don't know if those custom micros have a PGA, but some better DMMs use an external 24-bit delta-sigma ADC which typically has an internal buffer + PGA. But not sure how many shunts they use, probably at least two, since there are typically two fuses, smth like 10A and 200mA. The 10A shunt is always clearly visible but the low current shunt may be just an SMD resistor that may be hard to spot.
>>2550573>I don't know if those custom micros have a PGAIt's just an analogue switch or two per amplifier. Arguably it's easier to have multiple amplifiers and use the analogue switch to toggle which one goes to the ADC, or just have the brainbox have multiple ADC inputs in the first place.>smth like 10A and 200mAUsually the fuse is a bit larger than the amp rating, my meter uses an 11A fuse for its 10A range, for example. It doesn't have a mA range because I'm a retard who bought an HVAC meter.You could just have a single fuse branching to multiple current sense resistors, where the range switch completes the circuit, in the event you've got both mA and µA ranges. Arguably you could get away with PTC resettable fuses there, if not some sort of transistor-based overcurrent protection circuit.
>>2550108Cheers anon, really helpful.
>>2550282analog demux ic. youre already using a mcu so why not just get another chip
>>2550564>>2550560thanks to both, the ac case makes more sense.
OK, I can't find a solution by searching in internet. Send help pls!I need a working hobby-level solution to find an altitude of my drone without using GPS. Altitude range 0-100 m.
>>2550735The altitude above ground, I forgot the most important thing. Not above water level, otherwise I would use baro sensor.
>>2550735>>2550736You can still use barometric sensor. You just set altitude to 0 or relative to ground air pressure when you take off. Planes also do this. When they're about to land, air pressure at airport ground level is radioed back to the pilots so they can adjust their altimeters. Only other option is radar, but that's too complicated and too expensive.
>>2550747But ground elevation changes drastically and I don't have GPS to check position of the drone and the ground elevation at that point from memory.Is there laser measuring tapes which work on such distances? I don't need the precision, +-1 m would be totally acceptable.
>>2550749Laser range finders do exist, but they're going to be more expensive than just buying a GPS module ($4). What are you even trying to accomplish with altitude measurement? Considering how cheap GPS modules are why the no GPS restriction?
>>2550753You are right, but the GPS signal is being jammed, so no coordinates. I will try with lasers, thanks.Any input is welcome anyways.
>>2550756>but the GPS signal is being jammedWhat are you using your drone for? Dropping grenades on Russians? I don't want to give you any ideas if people are going to die as a result.
>>2550756>Any input is welcomeDo a suicide bombing on your own 'troops'.
>>2550758No people are going to die, don't worry about it.Do the small radar systems even exist for hobby drones? I can only find some certified radio altimeters for real planes with the dials which look like they come straight from 50s.
>>2550761>Do the small radar systems even exist for hobby drones?https://ainstein.ai/drone-makers-drone-service-providers/us-d1/https://ainstein.ai/drone-makers-drone-service-providers/lr-d1/But this only works below 50 m and costs $600. 500 m version is $5900.
>>2550768Holy fuck. But why would someone want this instead of $150 laser range finder with 2 mm precision on 100 m? Makes zero sense unless you are forced to use it because of said certification.
>>2550768Btw how does it work so this small box costs hundreds or thousands of dollars? I mean why cant china or taiwan just copy this?
chiner did 9/11
>>2550770Laser systems have their own issues which make them less reliable compared to radar.>>2550771RF magic + probably custom ASIC + FCC certs. Market for such systems is also quite small so price will be high regardless of how much it costs to make it.
>>2550756>GPS is jammedi find this hard to believe. different gps's work at different frequencies and modulations. in fact usa, russia and china all have their own satellites for this. plus others. jamming all of it in a wide area would also be massively expensive and take up a lot of space due to the size of the antennas required to "jam" the signal. if they went to this much trouble to block gps im surprised you can even post here or access the internet at all
>>2550847GPS comes a from a little tiny satellite running off a solar panel it can't even get light on all the time. The signal is weak as hell. It is very easy to jam and spoof. Truck drivers have been arrested for it before.
>>2550814> RF magic + probably custom ASIC + FCC certs.B-but on the other hand you don't need ASIC, because FPGA costs next to nothing and china gives no fucks about FCC.How does such box look like inside? There has to be an antenna - piece of copper/aluminum 5x5 cm. I've heard a term "phase array" or something like that, what is it exactly? Probably an oscillator on some easy frequency. And a receiver on that frequency. It all sounds super cheap and easy. Can I make it at home?
So is there any special sauce to some brands lithium batteries?Trying to figure out what a $15 cell can do that a $6 cell from LG can't, they have the same specshttps://lithicoretech.com/product/lithicore-18650-3500mah-battery/https://www.18650batterystore.com/products/lg-mj1-18650-3500mah-10a-batteryMy dad keeps buying new batteries from the local shop which costs even more than online and want to help him out.
>>2550962I only buy Sony VTC series and Panasonic NCR series 18650s because I know exactly what I'm getting.
>>2550962No. the cheapo ali express ones are the same that LG rebrand, but LG etc test them before selling. In m opinion, its worth spending a little more to have it delivered faster than 4 weeks, and have the units be functional. Ali is getting much better with refunds and siding with customers so generally claiming a refund is not an issue, it's just the effort and disappointment.
>>2550761>No people are going to die, don't worry about it.I agree, ukrainians don't count as people.Laser rangefinders work using a time-to-digital converter, theoretically it wouldn't be too difficult to use a radio emission instead of a laser, if you use a narrowband enough signal with proper filtration. If you have to do it synchronously via DSP (probably a lot more reliable) then you'd end up being limited to maybe ±10ns (100MHz ADC clock) of time resolution, in which case you've got ±3m of distance resolution. Give or take a nyquist factor of 2, idk. Doing that and having a laser rangefinder for the closer distances may be the best compromise, cloud shouldn't be an issue at the <20m range.Also see how those shitty ebay radar proximity sensors work.>>2550921>phase arrayThat's what you call an array of dozens or hundreds of antennas, each with their own individually controlled transmitter circuit so you can change the relative phase of the signals to steer the beam. For receiving they can be used to determine the direction that a signal came from. Take a look at the starlink receiver teardown.
Are there generic PCBs for SMD components? For THT you can get PCBs with a regular pattern of traces and holes.
>>2551074Do you mean protoboards? There are some protoboards that can be used with SMD components, pic related. There are also ones with holes at 0.05" pitch holes. Plus you can just mount a SOT-23-3 diagonally on normal perfboard. Deadbugging by gluing the IC upside-down and soldering jumpers to it isn't too bad either, you probably get better results than normal perfboard if you have a solid ground plane. Bonus points for twisting signal wires with ground wires.
>>2551095Your picture isn't too bad. Now I just have to find out where I can purchase them.But honestly, PCBs are a PITA. I know generic solutions are not adequate for some applications, and if you want to use BGA chips it's all over.
>>2551096Thankfully BGAs aren't that common for hobbyist stuff, usually you can get away with SOICs and QFPs. Maybe TSSOPs and QFNs, which you can use with breakout boards in a pinch. Honestly PCB fabrication from JLC has gotten so cheap there's not really any reason for a circuit-maker not to make an order from them a few times a year. Just have a backlog of projects to send to get bundled under one shipping cost. You should be doing that for components anyhow. I recommend designing multi-purpose boards with plenty of redundant footprints so they can be used for all sorts of purposes. Once you have all the critical components like crystals and bypass caps for microcontroller, or the passives and drivers for a mosfet half-bridge, it's feasible to wire them together with more crude methods. Be those crude methods protoboards, jumper wires, or home-etched boards. You can go further and just get the fab-houses to make protoboards and generic breakouts in the event you can't buy them elsewhere.I find there's some point where DIPs and SOICs and other proto-solderable components stop being available, and that's more or less the same point at which parasitics become unmanageable with a prototyping setup. Manhattan/deadbug prototyping is feasible up to a further point, and is arguably optimal for some RF use, but it is a massive pain. Wouldn't want to try deadbugging an LGA or QFN, let alone a BGA.
I bought a police auction shimano steps ebike a year ago (for $600 which is not great but it looked cool), but it turned out the bike was missing components adding up to about $500 (charger, display, speed button, mount, speed sensor magnet, and wires), and the battery life meter doesn't display when you press the button.So my plan is to replace the BMS and controller with chinese parts, and pray it will just work.When I opened the battery, it turned out that 9 of the series groups had 3.5v, but one group had 1.5v.I bought a TP5000 (which arrived today) to recharge that singular group, and I am waiting for it to charge right now.If it doesn't charge... I will probably buy the cheapest batteries I can find and use a knife to cut the bad group out, and solder the batteries using an iron. One downside is that I will not be able to get pedal assist, and it's probably not legal because the controller is designed for hub motors, and the speed limit uses the motor spin (plus a ratio) for limits, but because I have a shifting that value isn't accurate. I knew this before I started and I don't care because it's 250watt (the motor's rating) so it's not capable of going fast (maybe).right now it's at 3.4v (maybe 1 hour), I know that if a cell goes below 2.7 and you leave it at that charge for a long time the battery life degrades, but it would be great if it just worked a little bit so I can test the bike.Overall I spent about $200 on replacing the cassette and tools (the bike came with a 10 speed shifter, with a 7 speed cassette. the auction did not mention that).$100 on tools to open the motor (mainly crank removal, wrench, screw bits, and a torque wrench).$100 for the controller, throttle, display.$30 on the BMS$150 I bought a crimper, stripper, and a bunch of crimp bits and enclosures (not necessary could have saved a bit of money here, but I felt like knowing that I have to brute force the brushless phases, it would be nice to be able to quickly swap the wires)
>>2551143I just realized that it was in 3.6v mode
>>2551143Does the driver/esc do FOC?
>>2549084stick a piezo bender on it, cheap and cheerful
>>2551168Yea I think it's a sine wave controller and the motor should also be sine wave, I assume you are asking if my controller has 3 wires for the hall sensors.This was a forum post that made me confident this would work (but he made the mistake of using 48v when it's a 36v motor).https://endless-sphere.com/forums/viewtopic.php?t=96712
what adaptor/device would i need to dump an emmc memory chip? i wana explore larger firmware images
>>2551194sine wave and foc are not the same thing. foc implies measuring the winding currents, calculating a vector from that, multiplying that by the clarke and park matrices, including the throttle factor, and multiplying by the inverse matrices
>>2551074for SMD, you just cut tracks in copperAs needed:https://www.youtube.com/watch?v=vq968AFgPhgor just cut a generic grid
>>2551223FT2232H & CH341 are pretty common. You need an SPI programmer, or an SD card reader (SDXC) and modified microSD to SD adapter.https://www.riverloopsecurity.com/blog/2020/03/hw-101-emmc/
>>2549880>>2549965>>2550026I just discovered changeover reed switches.https://standexelectronics.com/products/spdt-changeover-form-c-reed-switch/
>have to make an account with ultralibrarian or snapeda to get rp2040 cad filesthis isn't very freedom oriented of you
Is this a good 3-phase motor driver setup? Can't get screw holes though the PCB due to how crowded it is, but I think I can get some clamping spars across the TO-220 tabs, else clamp it via the PCB itself.
>>2551545>I can get some clamping sparsno. bad.sounds like a job for Mr. 8-32 Tap and his merry band of Quarter Inch Long Screws.
>>2551563But how am I supposed to access the screws when they're underneath the PCB? Or do you mean tap the TO-220 tabs and screw into them from the underside of the heat-sink? Because that sounds like a nightmare of electrical isolation.Also I'll need a really thin electrically insulating thermal transfer pad to clamp these onto to prevent shorts, not really sure where to get that. Assuming normal thermal grease won't keep insulating everything when I crank down the screws. Maybe the nano-diamond thermal compounds are sufficiently rigid and insulating?
>>2550340>100,000 uf wet slug tantalum capacitorsThat sounds risky. There is unspeakable evil trapped inside of tantalum caps.
>>2550484>What i'm seing is the diode in series with the fan.Is it inline with the fan's Hall effect sensor?
>>2551572Thermal pads are made of fiberglass and silicone.https://www.westfloridacomponents.com/G321APF03/TO-220+Thermal+Transistor+Insulator+Pads+TO220+SIL-PAD+Bergquist+3223-07FR-54.html
>>2551524just make it yourself retard
>>2551576>thermal resistivity = 0.9W/mK>0.18mm thick>approx 12x10mm=120mm^2 metal area on FET>d = 0.18mm = 180E-6m>A = 120mm^2 = 120E-6 m^2>x = A/d = 0.67m>0.9 = P/(∆T*x)>0.9*x = P/∆T>thermal resistivity = 0.6W/KSo the effective thermal resistance is in the ballpark of 0.6? Getting maybe half that with sufficient clamping force? Considering I'm aiming for maybe 5 times that for the heat-sink itself it's not terrible at all. But if I'm not able to access the package holes I'd rather have a thin pad over the whole 2x3 FET area, instead of individual pads per transistor that would be a pain to align.Be nice if someone made identical FETs, but where the drain and source are swapped around in the two versions. That way you could clamp them to a heat-sink, with indium foil in between, and just take the + and - from two seperate aluminium heat-sinks.>>2551584I will.
>>2546753Tomorrow I'm making a marshmallows toaster with kanthal wire, aluminum food containers and some appropiate power supply. If it works I will invite my female neighbor for some cooz with s'mores.
>>2551631Are you planning to electrocute her so you can get her in the rape dungeon without a struggle?
>>2551631watch for the alzheimers
>>2551632I thought he'd set his house on fire.
>>2551639That's the grand finale.
>>2551298>https://www.riverloopsecurity.com/blog/2020/03/hw-101-emmc/>ZIF socket to sd card adaptor>not linked in a citation section of sortsgarbage website desu
>>2551298>FT2232HIsn't the FT232 more common? You don't need both the interfaces, so it's cheaper to just go for one of them.>CH341Wait that can interface SPI? I always assumed it was just another CH340, but I should get some of those. Is there an english datasheet or am I going to have to throw the pdf through google again?And wouldn't it be trivial to program SPI-based AVRs using such a chip? Feed the CS line into reset. But for some reason everyone uses those ATmega8-based things.
i have this thing, is there any way to turn it on manually?normally you turn it on by connecting 230V to go through the A1 and A2 but because reasons i can't do that, so do these things have some way i can mechanically turn them on?
I've got my hands on a handful of capacitors, resistors, and transistors. Any resources with lists of basic circuits a total noob should make to learn the ropes with just those components? Most shit I've been able to find requires IC components but I don't have any on hand yet.
>>2551828By "circuits" do you mean things to practice soldering, or designing schematics or boards? Or actual projects that you use IRL? Consider transistor audio amplifier topologies like class-A, class-B, and class-AB if your transistors are BJTs. At their simplest these are proof of concepts and decent practice, but with the right tuning components, heat-sinking, and careful design they can give decent audio output. If they're MOSFETs, then consider a ZVS switcher. Making your own discrete op-amp is probably fun too, some of the audio guys even do so for some reasons.See circuits here:>https://sound-au.com/If you're into audio electronics, you may well also find Lantertronics and Moritz Klein on youtube interesting, they both go into some reasonably complex circuits but offer very in-depth explanations. For RF stuff W2AEW has some really interesting stuff.There's probably more sources of simple circuits in the OP's "comprehensive list of electronics resources" link.
>>2551828If you have a at least M6 nut and thin enough insulated wire you can make an inductor as well and build a "LC tank circuit". That's pretty hands on and practical once you learn the math and can put the circuit into use, maybe by generating an audio signal for a small speaker (included in PC chassis) to get sensory feedback from your work. I'm just speculating from free courses on youtube university (shorts section). Alot of brown hands on blue backgrounds showing how to solder basic components into some more or less practical thing there.Transistors can be put into binary logic gates as well, but again you want some way to see what you are doing so get some LEDs to represent the bits as well. There's probably nice soldering kits in your local electronics stores showing you what is possible to build with the basic components that is included.This is the level I'm currently on and it's fun :)
>>2551831>>2551832Nice thanks for those suggestions, those all sound really interesting. For now I'm mostly staying with breadboard circuits and I am interested in digital and analog circuits.Looks like I'll be heading back to the shop tomorrow lol
>>2551833Get diodes as well to rectify AC to DC or just polarity protect your circuits. Accidentally frying shit will happen and diodes is one way to prevent it. There's several free circuit emulators online and in app stores which are helpful for building a theoretical understanding of electronics. It's possible to see current flow, voltage and temperature buildup etc. Neat stuff!https://www.falstad.com/circuit/
>>2551815>turn it on manually?the vast majority have a rectangular button on the front you can depress.like this: https://youtu.be/dIEEGi72CZo?t=121 (at 2 min mark)maybe yours is hidden under front cover.tho i dont see any seams, so maybe not.maybe that lil hole on the left.
>>2551828>learn the ropes with just those components?you have to build this one.it has the highest reward/cost ratio of any circuit ever built.
>>2550761>No people are going to dieTrue, Russians are not people.Why are you worrying about the GPS being jammed? are you in a war zone?
sup /ohm/ i recently got this battery pack for like a buck and i'd like to know how to use it withoug blowing up my house. should i use something like a TP4056 board?
>>2547618>>2547620NO, ABSOLUTELY NO ACETONEit dissolves plastics, the majority of themI think imbecile anon meant ISOPROPANOL which you can buy hassle free @ many places, and is used to actually clean electronic boardsIf you have deionized water you can even add a drop of dishwater soap and use a brush and scrub according to how robust the board components areThen rinse with copious deionized water, pat dry as much as you can and THEN use ISOPROPANOL to flush the water out, again and again.You can finish with an oven dry in 50°C, but not any more, I once went to 70°C cause it took too long and it melted some of the thermoplastic components.
>>2552257>I once went to 70°C cause it took too longI like you, Anon.
>>2551918lol, i have been thinking about this one. after looking at a lot of circuits, i definitely think i'm gonna need to branch out on capacitors. i have a pack of 100x 100nF ceramics which i got for a few bucks, and i'm quickly realising that's not even close to the capacitance i'm gonna need for more projects. i got a variety pack of resisters which was a good idea, but i should've got a variety back of caps too rip
>>2552134You'd want a 10S BMS board.>>2552257Acetone is fine for a lot of components, including a lot of thermosets, which should include resistors and the PCB itself. Solder mask softens in acetone, but I was assuming anon was working with protoboard. Solder mask also softens in acetone, FYI.
>>2552257>NO, ABSOLUTELY NO ACETONEabout the same time this was posted, i was using acetone to clean glue off my old monitor.didnt go so well.still, the removing-the-glue part went splendidly.
>>2552335Wipe it down with that black polish shit for car body scratches. Maybe even WD-40.
>>2552340or Armor All™
>>2552356or vinyl dye
>>2552329No anon, just steer clear of it, any plastic that gets exposed to it is more likely than not to get rekt.You want to degrease glass, use acetone sure, but on plastics no, anything other than HDPE or Teflon tape at risk.>>2552335A pity, tape display and spray paint bezel?
>>2551918Now build the mosfet version :)On an unrelated note, does anyone know how to keep the output of an isolated SMPS save in the event that the optocoupler's LED fails? From what I understand, the LED failing will prevent the SMPS controller from receiving feedback and will therefore continue switching with the output voltage increasing to dangerous levels.
>>2552310No need for despair, 100nF is not the end of the world, as long as you have large resistor values :). To compensate for the 100nF, increase the 100k resistors 100x so use a 10mOhms if you have it. Otherwise, you ca also put two capacitors in parallel to get 200nF and can increase the resistance to 5 mOhm, and so on. if you don't have 10 mOhm or 5 mOhm you can try to put resistors in series. It's always a good idea to get basic components like capacitors, resistors and inductors in multiple values, use the E24 for resistor and E6 for capacitor scheme (https://en.wikipedia.org/wiki/E_series_of_preferred_numbers)When it comes to other components, what you should buy depends on the type.LED: at least green/red since those are the basic ones with low forward voltages so you can run them off any microcontroller.Transistors: Buy general purpose NPN and on PNP models (the one I use are NPN: 2n2222 and its variants, 2n3904 and for PNP I use the 2n3906. Obviously this won't be useful for all projects, but for low power application they can't be beaten since they are dirt cheap). For mosfets, well the 2n7000 is a great and dirt cheap n-channel mosfet that can work on logic level, but p-channel mosfets are really hard to come by, especially cheap ones. You might also want some high power n-mosfets for those high power applications.You'll also want some op-amps for more advanced stuff (filters, amplifiers, etc.). Since these days most stuff are 3.3V or 5V, you'd want something that are at those voltages, and since those voltages are really low, you want a rail-to-rail op amp. I think the TL974 series come with dual or quad packages and can do 2.7-16V inputs which are more than enough for most projects.You also want diodes, which one you want depends on your application. For general purpose rectifiers, you can't beat the 1n400X series. They are dirt cheap but have a relatively high voltage drop (0.7-1.1V) and limited to 1A.
Is it possible to learn electronics on your own from zero knowledge to a level that you're competent enough to find a job in the field? Like telecommunications?Any tips or experiences?
>>2552464>the LED failing will prevent the SMPS controller from receiving feedbackIn a well-designed SMPS, the signal is inverted at some point. That is to say, the feedback is ultimately interpreted as "less light from the LED = output should be reduced". That way, if that circuit were to fry and kill the opto, the primary side of the power supply attempts to reduce output voltage to nothing.Failing that, protection circuits (like a crowbar circuit) should be in place to prevent damage to connected equipment.
Project for today:I found a mechanical keyboard cheap at a thrift store the other day, BUT it was wireless, and not bluetooth, and the dongle was missing. Fuck wireless that isn't bluetooth or logitech's star system. But in addition to a bunch of nice key mechs (off-brand browns), it had a good pillow battery.So I took the battery, its PCB connector, and a USB charger board (the kind that Big Clive shows as an example of the good kind), and a portable CD player and got to work.I like having a CD player handy when "digging" for used CDs, but the fucking batteries always run out and shit. Being able to recharge with USB means I don't even have to go back in the house, I can just use a car charger. I've been wanting to this for a while. What I ended up doing was soldering wires to the two battery terminals of the CD player (they were copper coated or something, so ezpz), and cramming everything into the battery compartment and covering shit with tape.And it works! It's happy with 4 volts, and I soldered to the AA battery terminals, so it's probably going to run a long time before it even needs to be recharged.As for the keyboard, I'm just going to ohm out the matrix so I can hook up a plain USB interface or something. I can't see them, but I can tell it's got diodes in there. Or I can desolder all the key mechs for something else.
>>2552479>Is it possible to learn electronics on your own ... enough to find a job in the field?1 chance in a million.employers need to cover their asses.demanding diplomas and certifications means that if the employee turns out to be a dud, HR doesnt get blamed.half of everything you do in life is avoiding blame.still, you can use PhD after your name if you have a Public high-school Diploma.
>>2552479In my experience learning the basics works better and faster if you are taking a course and actually doing the homework. (I took the free online course OCW 6002x.) You can't really understand this stuff on a deep level if you're just reading articles and watching youtube videos and glossing over the fundamentals. Also build yourself an electronics kit so you can have hands-on experience.As work, I think you're more likely to get a job at a company small enough where a technical staff member is doing the interview and not someone hired to manage "human resources."
>>2552479If you go full-autist and build yourself something really cool that gets employers to notice you then maybe. See Applied Science getting a job out of building a scanning electron microscope, though he still had a degree so it didn't really count. By the time you get competent enough to do such a thing, you can probably employ yourself. Try making a free electron laser, haven't seen one of those done by a hobbyist before.>>2552520>the kind that Big Clive shows as an example of the good kindWatch out anon, that DW01 chip has an overdischarge threshold of 2.4V, which is definitely low enough to damage a lithium ion cell.
>>2546753Does anyone know a component vendor who has through hole rca jacks with component, audio and composite like this? I cant see any on mouser
Is it a bad idea to buy 18650 cells from aliexpress?https://aliexpress.com/item/1005005094956317.htmlit ends up at about 2.6 euros per cell if I buy a 20-pack.Do these get held up by customs? (sending to Belgium). Are they just the same as the ones from reputable brands? Or are there separate factories producing shit cellsI got a bad battery pack for my newly bought second hand monowheel, 9 out of the 10 batteries show below 0.1V charge...I'll see if I can charge them but fearing the worst
>>2552640Maybe try to find a more reputable listing, but that price is about right for that cell
>>2552628How many do you need? Often you can find old cable boxes or dvd players at thrift stores. If you just need one, salvage it.
>>2552725probably a few thinking of making some psp go docks to sell
>>2552737Do you hate TRRS (4-pole) jacks? You could send the composite video & audio through that, and component through 3 RCA jacks.
>>2552744i think id would be nicer to just have all rca since its easier to get good cables
>>2552640Watch out for QC-rejects or salvaged cells.
Can any one identify these chips?They come from a QUIKTEL QUIKPAGER MODEL SMP-100 made by Canamex communications corporation board number PMB950808. 04I suspect that winbond chip is a 6502
>>25528991999-2000? I don't think Winbond made 6502 clones. It's more likely to be an 8051, but dumping the EPROM would show you for sure.but really...>scratch out chip markings on CPU and SRAMs>use plain old EPROM that anyone can dump>>2552922basado
Have anyone here used graphite sheets? I’m thinking on sticking reflective foil paper on one, cutting it into shape and putting some leds on it so it will help spreading the heat. The leds probably wouldn’t generate much heat anyway but they will be in a closed space made of plastic so I guess I could at least help a little with heat transfer but I have never used them. Would it be better to use thin or thick ones? Not exactly electronics but I guess you guys are the more likely to have dealt with this kind of stuff.
>>2553001Doesn't seem like enough thermal mass to be effective on its own.
>>2553036Supposedly they are good thermal conductors (different brand and also much thinner) https://youtu.be/ZAEhyY1_czM
How do i calculate the resistor to use on the base of a transistor?The base will be connected to an esp32 gpio, so i guess it's 3.3V divided by any resistor value that makes it less than the peak base current?
>>2552737Maybe just use hdmi
>>2553045The sheets are only good for spreading heat not sinking.You still need a proper heatsink.
>>2553169>I_base = (3.3V - 0.7V)/R_base>I_collector = hFE * I_baseSo use the largest possible collector current and the minimum hFE from the datasheet in that calculation. The hFE is also known as the beta or current gain, and is somewhat dependant on current. Typical minimum values are maybe 50 for a small-signal transistor, and 10 for a power transistor.
So I decided to make a V2 of that VNA test jig. I ordered proper headers and made a board that will have some 3M standoffs. Also using them as alignment points just testing stuff before my real first board design. Got a drill press accessory and proper tungcarbide bits. It went through it like butter with no hassle. Amazing what proper drill bits can do. Reduced copper tearing when it bores through the other side. I wanted to ask has anyone attempted to do tin electroplating? I want to avoid this tarnishing in some boards and figured I have most of what I need I could attempt it.
>>2553174I’m gonna use on led stripes. Supposedly the stripes are the sink already but since I’m using it in a closed plastic narrow container at least spreading the generated heat should help I think.
>>2552972thanks for the tip, I will do that and report back.>>2552922thanks a lot for the subtle jab, I loki googled it there XDbased, that was funny ngl
>>2553211I've done electroless tin plating, there's a nurdrage video on the topic I recommend watching. Though personally I find you can just keep the tin chloride seperate from the thiourea, and apply the solutions to the surface of the copper with a small paintbrush one after the other. Thiourea first, if I recall correctly.Tin chloride takes fucking ages to make with lead-free solder and HCl, I'd recommend trying to electrolytically dissolve it in ferric chloride, while pulling iron back out into a nail.It's also an option to electroplate tin (or nickel) on the board before etching, and etch through it. I think tin is hard to etch through, but nickel should be doable. You can't electroplate after etching since there isn't continuity between parts.Other options include:>tinning the whole board with an iron/hot air and plenty of flux>applying solder mask by brush or with some sort of mask>dip it into a gold solution>electroless silver plating
>jerry speakingand don't even get me started on double pole breakers, i mean what's the deal? is it 240v at the breakers max amps, or is it 120v at said amps? geeze louis guys this stuff is already magical enough! keep it simple for christ sake>laugh track, kramer interjectsJerry, Jerry! Don't you know the river analogy for current? I mean just look at my hair I'm _electrified_ brother don't you see it>jerry responds Ugh, no Kramer, but please keep any rivers away from my outlets while you're in my apartment>laugh track, george interjectsyou know, why do they gotta base amperage on height, I mean what's less powerful about a little wave? what's next, anti-bald guy electricity?
>>2553295>s it 240v at the breakers max amps, or is it 120v at said ampsthis was akshully a srs question though dudes
>>2553297read the datasheet and hope
>>2553300Shouldn't it be standardized? Is the amperage rating on a double the amperage for rating at 240v or 120v? It's my understanding double pols are 240v that are broken down into 120v. But I'm not sure what the means for the rating on the panel.
do trimpots have the same tempco and drift problems as carbon film resistors?
JERRY! LOOK AT ME RIGHT NOW, I'm running on 2^256W I stole from public municipalities and boy! Am I feeling it. That's Bitcoin kinda energy Jerry and I'll tell ya, it's better than the cleanest Columbian. I traded a kid a thanksgiving turkey for an electric bike and boy howdy can I ride now. All sortsa sights, sunset like yu've never seen. My veins are the size of otter pops. This stuff has MegaJules, Jerry, MegaJules. All organic too. There's all kinds of electricity out there Jerry you just gotta FIND IT>points and wiggles finger aggressively throughout
>decide to draw out the specs of a bunch of op-amps available at the local store>the real treasure was the OPA2134s already within my parts boxi am content
>>2553304Voltage ratings refer to when something will continue to function the way its designed. Amps are many electrons are moving.For a circuit breaker at 15 am p will break around 13 continuous. Either one will breaknandncause the other to break.
I'm trying to talk with a car ECU.In the red rectangle is a switch connector. Can I just connect that to a Raspberry Pi GPIO pin and set it to HIGH/LOW with a script?I think those GPIO pins output 3.3V, do I need a 3.3V to 5V converter for this to work?
>>2553349It's got a pullup to 5V already, I'd just add a transistor to pull it to 0V. 2N7000 makes it easy since you don't need an input resistor.
>>2553173the psp go supports component output already and i wanna connect to my crt
>>2553359Ah crap, I think I explained it wrong. Sorry.The pic is from a device that would normally connect to the ECU. But I am building a hacky setup to do it with a raspberry pi and a power supply that supplies 12V to the ECU. So the 5V pullup isn't actually there.You can think of connectors named X6 as the raspberry pi pins. CANSW, CANH and CANL are pins of a plug on the ECU.
I'm buying a CRT screen for a project I'm doing. What do I need to look for to make sure it will work with any modern Pc? Or will any CRT monitor do if I also buy the needed cables to convert the signal?Also can I safely say that if it works for a commodore it will work no problem with any modern Pc?
>>2553190Peak base current is 200mA, should i go for that value or should I keep a safety distance?
>>2553379If the signal source doesn't output an analog VGA signal, then you'll have to convert it for the monitor to pick it up unless there is also a digital input on the monitor.HDMI, Displayport, etc. = digitalVGA = analog
I know jack shit about RF, but would soldering a second antenna to the solder points on the antenna PCB give me a better BT connection? My switch seems randomly not detect the controllers.There's about 4m from the console to the sofa and the only thing in the way is a glass table but I still get intermittent lag or disconnects on more than one console, I've even tried disconnecting wifi and other appliances.So I've arrived at the idea of doubling the BT antenna.
https://www.youtube.com/watch?v=S7NQuZk1JmgVive la Buckethead.>>2553486I don't think it's the antenna, but if you go this route you have to disconnect the PCB antenna on the controller. That means moving an SMD resistor (0-Ohm jumper) or capacitor.
>>2553530I'm familiar with SMD work so no prob, but I don't really get what you're suggesting.The siwtch's PCB houses a Broadcom BCM4356 and I was considering popping off the connectors, connecting the antenas in serial to each other and plugging it back in.What else could cause these issues? lack of electrical shielding? other components?
>>2553542Okay, I see the ipex/u.fl connectors now (don't have any experience with the Switch). The physical length of the antenna element is important (wavelength). Too long or too short and you'll have problems. Is there any other device in close proximity that could be interfering? Try it in another room.
>>2553542Did you pair the controller with another device in the same room?
>>2553486most likely itll mess up the impedance matching circuit on the PCB and youll make it worse. bluetooth (even 4.x) works easily > 10m. send it back under warranty because somethings cooked if it cant work 4m away
>>2553549>>2553553Damn, so I can't go crazy and add whatever overkill antenna I want, I hoped I was able to even scavenge an antenna from an old laptop and wire it up.Can I measure the antennas impedance and order a similar impedence better antenna?>>2553550Nope, I've experienced similar drop-outs on another console in that same room and I don't know if I can analyze other frequencies in the room that are possibly causing interences/causing me cancer.I have a Chinese Xiaomi router broadcasting 1000 mW 30dbm and the same issues came up with the router powered down and all other home appliances turned off, also no neighbours I live in farmlands
>>2553562>Can I measure the antennas impedance and order a similar impedence better antenna?It's a 50 Ohm feedline. You can use the antenna from a laptop without a problem, just be careful when you push it on the u.fl connector. You should also use a magnifying glass to look closely at the PCB for cold solder joints.
>>2553305what material are they made of?
>>2553274I just bought some thioruea and the lead free tin solder. I got time to dissolve it and I can just keep it stored till I need it so that's whatever. I'll do it this method though because really seem to basically use the same stuff so I can always electroplate later but it's nice to just dump the board in and get an even result on the whole board. What kind of paint brush do you recommend? Would the hcl chew through a normal pain brush?
>>2553614The issue with tin(II) chloride, the stuff you want, is that it oxidises in atmospheric oxygen to form in(IV) chloride. What I do is add a pinch of sodium bicarbonate to the mix before putting the lid on so it fills with CO2 gas instead. Doing that I find it lasts a month easily, probably a lot longer. If you have an inert gas welding cylinder then you can skip the bicarbonate.>What kind of paint brush do you recommendMine says "S3028 Roman Sable Round" on it, the tip is brown so it may be real (horse?) hair. I haven't had many issues with things getting dissolved with HCl, though scotch-brite definitely gets eaten by it.
>>2553379>can I safely say that if it works for a commodore it will work no problem with any modern Pc?nope.the C64 used a 15Khz horizontal frequency, which was the norm for all old TVs.essentially, no modern video card can go that low.you'd have to get a video card with a composite output (or buy a box that actively converts VGA to composite) to get 15Khz.as to the CRT monitor, you'll have to research its capabilities to see what else besides 15Khz it accepts.besides tech specs, it'd be best to find info from actual owners of the CRT.
>>2553685The A/V DIN socket on the C64 outputs composite and S-video.https://www.lemon64.com/forum/viewtopic.php?t=72807
>>2553756It's page 8 mate
>>2553759There's at least a full day left in it because /diy/ is so slow. Fuck it, doesn't matter.
>>2553761Yeah but if I leave it longer it's more likely that someone else will make the thread and forget the title, or that I'll forget about it and nobody at all will make it before it archives. Page 8 has been the standard on this general for a while now.
I hate when threads get split like this.
>>2553636You drop the sodium bicarbonate into the acid + tin(ii)? I would think that would neutralize it and cause other issues. Though I suppose once the reaction is done you dont need an acid solution anymore just an aqueous one. Just want to make sure on all this if anything I can make small amounts. Oh what about clean up. Not sure how hazardous these chemicals are to dispose of.
>>2554209Just a tiny amount, as to not significantly neutralise the acid. I do it when the tin is still reacting, because it takes a few days to build up concentration, and like a week or two to dissolve fully. I use excess acid anyhow, though going full stoichiometric isn't a bad idea at all.
this shirt electrocutes you while gamingbut it's too expensivehow can i diy one for cheap?owogame.comShould i just buy some of those abs excersise things and hook it up to an arduino or such?Seems like the basic functionality is pretty easyyou have pads attached to you body and then use CC power source to run say 2ma through the skin
>>2554700It's just a glorified TENS machine. That's a lot of electrodes, nigger. Do you have to grease yourself up with contact gel before putting the shirt on?
This thread is about to get archived. 2 days after dickweed >>2553755 jumped the gun. Take note, faggot.
>>2555005Cmon guys, when I first started leaving it to 8 days people would complain like "where's the new thread" and shit, and now I get the opposite? Whatever I do people are going to complain.
still not archived
what sort of 12v power supply/adapter does this use? I already asked /g/