busted thread: >>1606134>RULES0. Electrics ≠ electronics. Appliances/mains stuff to /qtddtot/ or /sqt/. PC assembly to >>>/g/.1. Do your own homework. Search web first. Re-read all documentation/datasheets related to your components/circuits. THEN ask.2. Pics > 1000 words. Post relevant schematic/picture/sketch/9001.5 hours in MS Paint with all part numbers/values/etc. when asking for help. Focus/lighting counts.3. Read posts fully. Solve more problems than you create.4. /ohm/ is an anonymous, non-smoking general.>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>Project ideas:http://adafruit.comhttp://instructables.com/tag/type-id/category-technology/http://makezine.com/category/electronics/>Principles (by increasing skill level):Mims III, Getting Started in ElectronicsPlatt, Make: ElectronicsGeier, How to Diagnose & Fix Everything ElectronicKybett & Boysen, All New Electronics Self-Teaching GuideScherz & Monk, Practical Electronics for InventorsHorowitz and Hill, The Art of Electronics>Design/verification tools:LTSpicefalstad.com/circuit/circuitjs.htmlNI MultisimCircuitLabiCircuit for MacsKiCAD (pcb layout software, v5+ recommended)>Components/equipment:Mouser, Digi-Key, Arrow, Newark, LCSC (global)RS Components (Europe)eBay/AliExpress sellers, especially good for component assortments/sample kits (caveat emptor)Local independent electronics distributorsladyada.net/library/procure/hobbyist.html>Related YouTube channels:mjlortonjkgamm041eevblogEcProjectsgreatscottlabPhotonvidssdgelectronicsBigClive>Li+/LiPo batteriesRead this exemplary resource first: https://www.robotshop.com/media/files/pdf/hyperion-g5-50c-3s-1100mah-lipo-battery-User-Guide.pdf>I have junk, what do?Take it to the recycler.
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Repostan:I'm about to have work done on my workspace's roof so i't s the perfect opportunity to remodel/restructure.I'm currently looking at an empty 12m x 5m room, what should I do with it? Any cool workshop pictures I could use as inspiration?
You know how on arduino there are rx and tx pins on serial? If i want pull rx high do i have to use a resistor to limit current, or can i hook it directly to 5V?
>>1610590I want to fix an old guitar speaker that I bought at a swap meet & got kinda burned on. What I did not know at the time was that the speaker had issues, and the voice coil was damaged. I can not find a voice coil that is an exact replacement, so I was thinking of buying one that roughly meets the size requirements, and then modifying it to meet the right size. The one question that I have is how does the width of the coil winding effect speaker performance? All the voice coils that I find that would fit have a slightly wider winding, and I want to know if that would impede with how the speaker performs in any way.
>>1610602no appreciable current flows into CMOS digital inputs whose levels are within the rails anyway. if you want Rx high always, just wire directly to Vcc>5Vno, Vcc. if your arduino has a 5V Vcc then you can treat them the same, if not, then you can'tall that said, you could just switch on the pullup for that pin in code, no?
>>1610602since the Rx pin can be programmed for various purposes, it's possible you'll try out a program that makes it an output, and if it's connected to Vcc, you might get a short. a cautious arduino-fag would use a pull-up resistor.
>>1610607>>1610620I see. I am trying to hook up this serial communication.I assume the transistor is used to modulate the signal, do you think it would work with a mosfet instead? probably not right? since it would be mondulating as sort of a square wave and not a sine
>>1610632>mondulating as sort of a square wave and not a sinewat sine? this is all digital: 40Khz signal being modulated by the serial stream.the BJT is simply turning the LED on or off fast, so any FET will work exactly the same as the BJT assuming it's the variety that turns ON when you apply a positive gate voltage.
>>1610632works fine with a MOSFETdifferent members of the arduino family use different logic levels. some newer duinos run at 3.3V logic even at 5V supply. check your board's documentation and wire Rx to whatever the correct logic-high voltage is
gimme some project ideas - i feel like designing a pcb. I want to do something fun and challenging
>>1610640DDR2 or DDR3. mass delay-matching is always entertaining
>>1610643something a little easier lol
>>1610640>>1610645Audio PlayerHave a uC read raw data (PCM) from a file on an SD card and push it through a DAC to play musics.Bonus points for at least 16-bit 40 kbps quality
>>1610648>not supporting mp3 or MP4 AAC>2019I mean, there are some upper-end micros with adequate RAM and flash on board that you could build libav and link a simple directory enumerator and shell with them. and then there's that BeagleBone SiP>>1610645speaking of, a BeagleBone PC-in-keyboard might be a little easier and more fun. or, more generally, something you could actually use pretty often and would like to enclose or conceal inside some other small form factor of your choice. maybe a Bluetooth two-way makeup mirror idk
>>1610645besides, meandering traces are totally relaxing
>>1610656>Listening to compressed musicDisgusting.But its actually easier to just play PCM data than have a uC try and decode it. The Microchip dsPIC33FJ64GP802 is a 28 pin uC, runs at 40 MIPS (internal clock) and can play 16 bit PCM data. Wire up an sd card, pull the bits into the uC with SPI, use DMA to send it directly to the internal DAC, output to opamp of choice. Boom, music, and it still has tons of headroom for controls, display, even light DSP for effects.
>>1610533>>1610401Okay. I was actually wrong. It was my shitty wiring arcing due to higher vibrations at lower speeds. I wonder how ECU didn't blow up...
>>1610659I love wiggly traces, it's such an engineering solution.>hey this signal is off by x nanoseconds, should we buffer the input with a cap in silicon, extend the timing windows, what>just make the wire longer>>1610668kek
I'm trying to come up with some circuit ideas using the 4017 counter IC. Made this simulated toy circuit for controlling a traffic signal. The idea is to use this circuit with a microcontroller to control many (or all) traffic signals of an intersection. It works by first setting the "Enable" input high, followed by a "Reset" pulse and then clocking required number of "Data" pulses into the 4017 counter IC. The aspect is changed after setting the "Enable" input low. The outputs 1..4 of the 4017 select a different light combination. - 1 clock pulse: red, - 2 pulses: red+amber, - 3 pulses: green, - 4 pulses: amber. There's also a fail-safe watchdog function. If the "Enable" signal hasn't changed after a certain time period, the 4017 counter is reset to "0". This starts flashing the amber light, indicating that the traffic signals are not functional.The current version is kind of crappy as the lights can't change simultaneously. Would need to have some kind of "strobe" signal.
>>1610717Here's the internal connections of the controller blocks.In this simulation I'm using a shift register to implement the fail-safe counter. However I think in a real circuit a 555 timer could be used instead. Falling edge on "Enable" clocks the output D-flip flops and transfers the 4017 count value to the outputs.
Once i etch and solder my pcb, what can i do to prevent the cuprum layer from degrading?
>>1610722Cover it in some water-tight material, like elmers or plumbing glueAlso, call it copper
>>1610731>copperlike some common low born serf? no thanks
>>1610722either manually tin it with solder or use liquid tin
>>1610667>he doesn't into FLACwew>internal DACy tho, I2S interfaces are pretty common on 32-bit micros and stereo 16-bit I2S DACs can be alibayed for like 15 cents. ye olde ubiquitous 32F103 would be just fine here>>1610722https://en.wikipedia.org/wiki/Conformal_coating>>1610717you should have bought a rail of 'HC595s instead>The current version is kind of crappy as the lights can't change simultaneously. Would need to have some kind of "strobe" signalyou could also be crafty on the MCU end, asserting enables 1-4 data cycles before the change and releasing them all at onceor you should have bought a rail of 'HC595s instead
I bought a Bench power supply that's old. Like about 20 years old. (Sat in a hoarder/seller's place for years)Every time I try to drive the voltage higher than ~5.5V it starts making clicking noises and the Voltage drops by 75% and it cycle backs. Works like a charm under that.I'm replacing the El.Caps with new ones even though they tested fine ~10%.Diodes, Resistors & Pots are all fine. Should I also remove and test the Mosfetts & Transistors?There's also two Mechanical relays no longer manufactured.
>>1610772notice how the transformer has a whole bunch of windings. what it's doing is switching from one winding to the next as you increase the output voltage. (this keeps the output transistors cooler by having a smaller input-output differential.) it sounds like one or both relays are bad/dirty. replace 'em. alternately, you can remove the relays and hardwire the winding which gives the highest voltage across the huge filter cap. you can keep the transistors alive by not letting them get too hot.
>>1610769>he doesn't into FLACStill have to process the data, raw code means more free CPU time. Plus space is getting CHEAP these days, praise the NAND gods!>internal DACinternal DAC is just a bit faster, no need to interface to anything external. Bust out some DMA channels for internal processing. Saves some space too.I'm working on a 32-bit DAC player that uses I2S interface to an external DAC from the DSP. Each to their own, they both work.
>>1610786Thanks you so much I'll get working on those relays.Makes sense as to why the Transistors are not heat-sinked like I've seen sometimes on recent ones.
>>1610668holy shit lmao>>1610571That's really neat looking, I wonder if any hobbyists have attempted to make such a thing?
I want to make a cheating scientific calculator.>take calculator like pic related>remove its blob chip>design a PCB with micro, LCD controller and SD card slot.>???>doneThe question is, where can I get such LCD controller, or I'm better buying thicker calculator and replacing its screen with pre-made 16x2 with I2C bus?
>>1610907I think this would be more suitable, has more space inside.
>>1610907>>1610909Cheating scientific calculator? What?Like something you can have regurgitate information from an SD card?
>>1610907A micro with a big enough pin count could be its own LCD controller, or just use some latching shift registers like an edgy dude.
>>1610769So using an acrylic spray for cars should work on the pcb?
>>1610975Yeah, normal spray-lacquer/clearcoat should work. But watch out if you need to have some level of heat-tolerance that wouldn't be needed on a car exterior.
>>1610636>>1610639Yeah i am retarded, the modulating signal is at the gate so it's a simple square wave i just realized.I tested it and it works great.I want to add this as a communication for lots of my IOT devices and am deisgning a pcb for it and will send it over to chinks to make it for me.Do you think the schematic provided is fine as is or should i add some magical caps or resistors etc somewhere for increased stability?
Projects planned with parts ordered and received for them: 25Projects with parts on the way: 4Projects actually finished: 2FUUUUUUUCK
>>1611012Wow that's like me, except only like 15, 0, 1
>>1610923Yes.>>1610961That would be pain in the ass. Specialized ICs exist, why not make use of them?
>>1611035Why don't you cheat by putting the information in your own memory instead?You can't get caught looking at that
>>1611035Well if you were short on room, like the others were implying. That sort of specialist IC usually needs to be ordered from someone like DigiKey or Mouser, who I've never ordered from because of their shipping costs.>>1611044I'd prefer printing a counterfeit drink bottle sticker with answers written where the ingredients should be, and fill the bottle with water. Not that I'd ever cheat, as it incentivises the tests to be made more difficult for the next year in order to get the same pass rate. Assuming its a low-volume test (doesn't have thousands of people sitting it) that is.
>>1610961LCDs like that have multiple backplanes and are quite difficult to drive. You really want a LCD controller for that.Since space is an issue, he should look at MCUs that have an integrated LCD controller.
I'm designing a PCB for a project. Under my PCB are going to be two rotating neodym magnets. How badly is it going to affect the circuit? The PCB is only supposed to connect a two sensors with a Pi Zero W.Is making a ground plane enough or are there different methods to shield?
>>1610907I did a bit of research into this, because I had the epiphany that a calculator is just a computer, and i could therefore put whatever i wanted to on it.i considered ripping out a calculator shell and putting in a raspberry pi type thing. there's a forum where people develop programs for the TI line of calculators, and one guy there is basically making a calculator himself, and has plenty of information on it.the ultimate thing that stopped me was two fold. 1, wiring the buttons up to something is apparently very difficult. there's some sort of proprietary harness that texas instruments uses, and you'd need to build something that would allow the keypad to interface with the raspberry pi.2, i was unsure how to mount the screen in the TI chassis without having to extend the depth or width of the case.https://hackaday.com/2018/03/04/graphing-calculator-dual-boots-with-pi-zero/https://www.cemetech.net/forum/viewtopic.php?t=13127&start=0https://www.cemetech.net/forum/viewtopic.php?t=14513&start=0
>>1611064I need to go back to my custom calculator project.I used a cheap Casio clone. To interface with the keyboard (which is connected through a glued on flat cable) I cut off the original controller, scratched off the solder resist, and soldered wires on to it.
>>1611064pic related. i'm pretty sure there isn't an easy way to make the cheating calculator you want to make... which is unfortunate, because the TI84 has been around since 2004, has 24 KB of accessible memory, and still costs 100$. it's nuts.
>>1611059You could easily get a few mV induced in your circuit with strong Nd magnets, you'll probably want to minimise the change in flux. Ideally put opposing current paths as close to one another as possible, or otherwise use something equivalent to a twisted pair or coaxial setup such that all the change in flux cancels out. A sample circuit diagram (and the positions and orientations of the magnets) would be a good thing to post if you want some less vague criticism.>>1611068Can't you just test which button corresponds to which wire via trial and error (logic analyser might help) and feed them into a USB keyboard controller IC?
>>1611069folks on the cemetech forum mention using a microcontroller (MSP430) to relay the keypresses. The pi is apparently slow at handling the keyboard matrix on it's own, and would waste a lot of time.https://symbolibre.org/is a french project working on this sort of thing, but no clue how their development is going.a dude on the cemetech forums went through the trouble of making a PCB rather than interfacing with the one already in the calculator, if that's any indication. Obviously, you'd want the keypad to look and feel legit, but it seems like a real motherfucker to pull off.
>>1611073>microcontrollerReasonable enough, for that kind of multiplexed(?) keypad the only other method is with a few shift registers. But I think either way you'd need external transistors since you want to pull up the rows and pull down the columns, if my brain is working correctly.
>>1611075bear in mind i'm not the original asker, i just think it's interesting because i thought about doing the same thing.this is the schematic for a casio prism, and the TI layout is pretty similar.
>>1611073An extra microcontroller is a bit of a waste.They make dedicated ICs for key matrices.
>>1611079This is probably true.
>>1611079it does seem a bit superfluous. surely it would be better to use a dedicated IC since the only purpose of the microcontroller is just matrix math before handing off to the pi.
>>1611069It's going to look like this more or less.My plan is to place the circuitry as far away as possible from the magnets.What you mentioned sounds good. But isn't capacitve inductance going to become an issue when placing traces too close to eachother? I suppose that's going to be the lesser evil though.
I just came back from work, i don't have to work the next 3 days and am about to enjoy a delicious lunch in my underwear, while exploring this chinky logic analyzer that some anon here recommended to me.I paradise exists, this is it.
>>1611044I have no fucking intention remembering stuff I will never use.>>1611053Well, you can get IC on Ali Express.Also, bottle trick is known and I got caught not even once with that. Writing shit on calc is much more efficient, but that sliding cover can't fit much information.>>1611067Interesting. I want to keep stock chip though.>>1611068Graphical calcs aren't allowed.
the TI84 keypad interfaces with the switches on the board, and i was thinking maybe you could use some other sort of "grid of switches" underneath to intercept keypresses.see:https://d3nevzfk7ii3be.cloudfront.net/igi/UyN244LUKGA4dDpF.mediumhowever, i just found this:http://www.datamath.org/Graphing/NSpire_84KBD_BL_Y.htma drop in keypad for the TI-Nspire. It pins out in a convenient location, and might be way easier to tap into with some sort of ribbon cable, rather than the tiny array on the default TI84 board. maybe even... easy...
>>1611091wait, what problem are you trying to solve by cheating? if you can put programs into your calculator, you can put text into it.
>>1611085Nah looks like you'll be fine. No looped traces near the magnet at all. You could do the calculations with Lenz's law if you can measure the magnetic field strength with an analogue hall sensor, but considering I couldn't get an appreciable voltage (i.e. less than 1mV) from a bike computer magnet spinning at top speed half an inch away from a a 220µH inductor, I doubt you'll have any issues.>>1611086Oh hey, mine arrived too. I probed about a bit with it with Pulseview, which works great, except for the fact that my analyser's probes go from 1-8 not 0-7. Might make my own label to amend that, and of course change the leads around such that 0 = black, 1 = brown, 2 = red, etc.In some ways the 1-8 made more sense since it left the black wire to be 0V, but fixing a sticker is much easier than worming into the hardware.
>>1611095Shitty memory, and I'm nervous fuck, which makes me forget fucking everything.And by writing I meant writing with pencil on plastic. I just want level up this.
>>1611099program as in does your calculator have a program function. input your notes as a program.
>>1611101We are not allowed to have programmable calcs. Otherwise it would be easy
>>1611101>no smart text wrappingyikes
>>1611005it'll work, sure, but the transmit side has a minor power efficiency issue that you could address in software just by stopping the square wave out when not actively transmitting>>1611012is that your year-to-date?t.6/2/1>>1611069>USB keyboard controller IC?iow, a microcontroller>>1611075y tho, when you can simply tri-state the outputs almost as easily as you can set them low or high>>1611079yes, but they also are generally sold in larger packages than micros (for shitty chink-television-tier 1-layer boards), and most have bizarre host communication protocols (like I2C with no address byte)... oh, and might not have the rollover to handle all those shift keys
I have a digitized signal that looks like pic related.Whats the term for those 1LSB spikes and what would be the propper way to find the location of the local maximum?It seems like something so basic but I'm having a hard time finding information since I don't know the propper terms.
>>1611205Not sure of the spike names, perhaps accuracy? I'm assuming you're reading a DAC output? Some DACs have an accuracy rating that pretty much says its Vout is accurate within 1bit or something of the digital value.Need some more info on what you're doing exactly.
>>1611205quantization noise?a simple weighted-sum low-pass filter in software will help a lot, but if you want to try to accurately measure <1LSB try adding a small (1 LSB p-p) high-frequency (<1/2 fS) sine or triangular wave (aka dither) into the input signal before the ADC
>>1611221Background:I'm using this data aquisition module: https://www.meilhaus.de/en/redlab-204.htmI'm sampling a voltage at 250kS/s for 0.5s = 125000 datapoints.I use LabView to work with and visualze my data. I get the data as an array of floating point numbers.I made a sketch of my full signal. I want to find the timing of the local maximum and minimum as illustrated.the smal peaks in >>1611205fill my peak detection with false positives.
>>1611233I see only 18 counts (~4b) of amplitude. I think you need a lot more bits
>>1611255It's the verry peak cropped out so you can see the bits.
anyone know how pin symbol is called in kicad? i need to place some simple pins onto my pcb and can't find them in the library
>>1611229if I do a mooving average I still end up with with multiple, though smaler peaks.
>>1611261You mean a normal header?In the schematic editor they're just called Conn_....The footprint would be like: something header something 2.54mm
>>1611261in the schematic editor? try Conn_01x01 or search for test point>>1611262if you don't need that 4us resolution, could you oversample? also there are other filtering algorithms you can try, maybe a sinc filter would be best for precisely locating something like a peak?
>>1611264>>1611281thanks, thats perfect
Oh man, my uni has a bunch of scopes and function generators just sitting in the physics lab, no clue what they're going to do with them. Here's the front, they've got everything from those 20MHz ones on the left, to most of those middle 50MHz ones, to 3 or 4 100MHz ones, all Hitachi.
From the back you can see more of the Hitachis, as well as some stranger looking function generators, as well as an ancient Telequipment 10MHz model. Looked up a datasheet for it and found one, on the Radio Museum site. Is it bad that I want the 10MHz model more than the 100MHz model?
>>1611671you should ask about them. Analog scopes are going out of style fast- who wants to train students on outdated equipment? if you make the acquaintance of the right people, you can get loads of free equipment from a university.
>>1611698>- who wants to train students on outdated equipmentHahaha i see you've never been to college
>>1611698Well I find them easier to learn the ropes on, not to mention this lab rarely requires anything over 20MHz, but I can certainly see where you're coming from. I'm unsure if they're dumping them or if they've just got them out for recalibration. Already got a little swag from my uni (digital logic trainer), so I guess I'll ask about the scopes after the weekend is over.>>1611725I see you've never been to a good college.
If i have a relay rated for burger voltage but spec says that absolute max switching voltage is 250v,can i run it on 230v longterm?
>>1611754250VRMS or 250Vpk or 250VDC? Because 230V AC goes up to 325Vpk. DC also needs to have better open isolation in order to cut arcs that would otherwise be cut by the 0-crossing of AC.
>>1611757Doesn't really say.Just says 250Vachttps://www.tme.eu/Document/cb545971aaf7e641179e4750a1704dc9/HFD2_en.pdf
>>1611765no, you can only use it for 125V250V is a stress rating and prudent engineering dictates that one stay a safe distance from it
>>1611765then that's RMS
>>1611766>>1611767fuck.i can't find any two coil relay on ali that is 230V ratedall they sell are those regular blue ones everywheredamn chinks
>>1611769Tried searching for 240V and 250V?
>>1611771yes, but all i can find ever are single coil relaystwo coil seem to be unicorns
Yay! My masterpiece if finally finished. My first ever pcb.Can't wait to try and make it for the first time as well.
a two-for-a-penny CAN transceiver: the humble B5819WS Schottky diodewebm related: the sender with the key pad sends settings to the bus. both receivers hear the settings changes and act accordingly
>>1611778*ACK accordinglyalso notice the fade and (if you can see it in the blown-out video) the gamma correction implemented on the receiverswebm related: the "sender" bluepill has an F072 aboard. so I can use CAN and USB at once. here is a soft-USB-serial session with my CAN monitor, where I send a message to turn on updates for channel 0 at 50 hundredths of a second and receive analog input back. starting around 33s I start turning the pot connected to that input
>>1611776Congrats! only 1 right angle.
>>161178090 degree traces bad is just a meme
>>1611789They matter in rf
>>1611789Not bad, unnessecary. #2 looks odd compared to all others. No need to change anything.
>>1611776I'm back from grocery shopping time to will my magnum opus into existence
>>1611795Shit i didn't notice that i will fix it to 45 like the others
>>1611797fix that right-angle trace
>>1611797>>1611808Something like this
>>1611809Yeah I know I didn't notice it before
>>1611810KiCAD sometimes just does that, you sometimes have to really force it to go one way instead of the other. But the resulting aesthetic PCBs are more than worth it. Mind me asking what those big circular pads are for?
>>1611780>>1611794>>1611808Right angles are only a problem if you etch at home or have to deal with microwave frequencies.https://resources.altium.com/pcb-design-blog/pcb-routing-angle-myths-45-degree-angle-versus-90-degree-angle
>>1611813Of course they don't actually matter in almost all cases. But they make your PCB look worse.
>>1611789Anything with a frequency component (i.e. AC, RF and things that turn on and off) will reflect off the corner. Whether that's a problem if another matter, but at the very least it's bad practice and a bad habit.>>1611727>>1611671>>1611667If you do end up having these available to buy, remember to see if you can get the service manuals, if the things have any known problems or ""unobtainium"" (often less of a problem than people make out tho), that the CRT is not on its last legs or that there are some tubes available for replacement, and of course to get 2 or 3 so they can eventually cannibalise each other.
>>1611814>But they make your PCB look worsewho caresalso subjective
>>1611816>get 2 or 3 so they can eventually cannibalise each othermate I barely have enough room in my flat for one of those things, though I would like to try experimenting with turning a scope tube into a vector monitor for a computer (i.e. all the computer graphics are turned into lines traced by the oscope as a really complicated dynamic Lissajous pattern)I'll remember to ask for the service manuals thanks. But considering their age I can probably get them online. Like the Hitachi VC6145 service manual that shows up first on google:https://elektrotanya.com/hitachi_vc6145_oscilloscope_sm.pdf/download.html
>>1611820>mate I barely have enough room in my flat for one of those thingsThen do what you can.
>>1611812Plastic leg holes
May I present to you:Gondolacap ceramic editionsuggestions are welcome
>>1611834With a number:
Electric motors are technology... I meant electronics.Is it possible to rewind a BLDC motor, so I have more torque? I don't need speed that much, to be honest. I just need to wind more turns, right?
>>1611839with body shading:
>>1611844Final version with lead shading and transparent background. Sorry for the image spam.
>>1611847I like it. Make some more gondola parts and it may become a nice image to use for future generals.
Very basic question here: I have 16V (or so) AC and need around 3.3V DC. I thought about using a diode bridge to turn AC into DC, like pic related and then a Resistor to drop it to 3.3V. Three questions:1. What DC voltage will I have after the diodes? Wasn't there something like a factor of √(2) or something like that?2. Would some generic 1N4148 diodes work?3. What resistance would I need to get 3.3V? I thought about using kirchhoffs voltage law, so I would know the voltage that the resistor is supposed to drop is X-3.3V where X is the supply voltage. I can't solve U=RI though because I don't know the current needed. I don't know the current drawn/ the resistance of the ESP8266 I want to power either so I can't calculate it. Any thoughts? Thanks.
What the fuck flatcam?These two things aren't even fucking similar.What sort of garbage gcode is this?
>>1611857>I don't know the current neededWell that's your first problem. Then once you've got that, use a suitably rated linear regulator.
hello, got a question about control theory.In class I saw that control algorithm are written as recurrence relation in source code but why I never see that on internet ?Every time I look for PID examples they all use the same technique : an integral with *dt and a differential with /dtExample : https://github.com/br3ttb/Arduino-PID-Library/blob/master/PID_v1.cppInstead of something like :output = Ki*sample[n-1] + Kd*sample[n] + sample[n-3]Someone knows ?
>>1611233The DAQ you're using is only 12-bit at a +/-10V input range (20V total). That means that the resolution for your digital data is 4.88mV per bit.You are getting those spikes because the signal is going between those 4.88mV levels and the ADC can only read is so well. If you had a higher resolution ADC, say 16 bits, those spikes would be much smaller because your voltage per bit becomes only 0.305mV.Its simply a limitation of your hardware.As far as programming around them, you can always select a section of data, and if you find a peak, compare its value to the values of the data before and after it. If the data values before and after the peak are the same, and the peak value is 1 bit higher, you'll know its a spike.X = "peak" dataCompare the values of (X-1) and (X+1) data points, if they are equal, subtract one bit from the X value. If X is now equal to (X-1) and (X+1), its probably just a spike.
>>1611841Its possible, but it would probably be much easier to run the motor through a gearbox, or even just two sprockets and a chain.
>>1611857IF you need regulated 3.3v for a uC, get an actual regulator. Dropping 16 volts to 3.3 with a linear regulator is a bad idea, it will probably dump a lot of heat. Look into a switching regulator.
>>1611869Different Programming styles.At the end of the day, if it works, it works. Most people don't care about speed or efficiency, just end results.
>>1611862Ah, much better.All i have to do now is to tune the line width settings and such and then i will be able to print the artwork on the pcb, draw a silk screen with the same pen, and then swap the pen for a drill and let it also make the holes for tht and suchI could probably let it even draw a soldermask onto it with something other than a sharpie since i don¨t think sharpie can resist solder awfully well
>>1611877You can buy solder mask cheaply from Ali.It's UV cured, so you'd normally use a transparency but you could experiment with mounting a uv laser on your printer.
>>1611877Shit i can't seem to figure out how to change flatcam from milling to drawing, so instead of milling where copper is not supposed to be it mills (draws) where it IS supposed to be>>1611879The problem with solder masking is that it is yet another step for every single pcb i do, so i will maybe just solder it with out the mask and use a transparent resin spray pain for protection from elements
>>1611872It is direct drive hub motor. BLDC or PMSM (I don't know). So, gears and chains are not only less efficient, but also pretty difficult to fabricate, since you would need welder and probably a lathe and I don't have such toys. If I had - I would make entire scooter myself.Rewind seems to be more reasonable option, which should solve two problems: high resistance of windings, and high KV. It is much easier too, disassemble the wheel, desolder windings (Y arrangement) and wind new windings unsung multiple wires. Since it is low voltage, would have only 10 turns max per thing you wind in, tooth of stator, IDK
>>1611970I want you to know I love you anon, with all my heart.
>>1611975thankslove you too
>>1611879>It's UV cured, so you'd normally use a transparencyUse high quality tracing paper, transparencies never work very well.>>1611902>The problem with solder masking is that it is yet another step for every single pcb i do, so i will maybe just solder it with out the mask and use a transparent resin spray pain for protection from elementsThe process in >>1611877 is way more involved than masking and etching, honest to god man. >>1611869The one you linked to is really very verbose. PID loops are being used more and more now by non-specialists with code/control, so that's likely to be for a biologist or chemist or something so they can be hands on with making the equipment for experiments and what have you. Maybe google is selecting those results over more "technical" (normal) ones because they've become more popular? Also a lot of forum posts are copy pastes, as is a lot of working code unfortunately.
>>1611813>microwave frequenciesthat's just about par for the course anymore>>16117767/8 triggering, very good>>1611812no you don't. try the / key>>1611854saved for next OP
>>1611841> Is it possible to rewind a BLDC motor, so I have more torque? I don't need speed that much, to be honest.Will the core accept more copper (both in terms of space available and saturation flux)?> I just need to wind more turns, right?Right - assuming the core isn't saturating. If it is, then more copper won't help. If you're designing a motor from scratch, you use more poles for higher torque and lower speed.Flux is proportional to turns and current, so using fewer turns of thicker wire (or more turns of thinner wire) doesn't change anything (double the turns, half the cross-sectional area of the wire => half the current, double the resistance, same flux, same voltage drop from resistance, half the I^2R losses). Although inductance increases with the square of the number of turns, so you need a higher voltage for a given speed in spite of the lower current.
>>1611970why do you hate yourself that much?
>>1611987What does PID look like in pseudocode? I know I could handle it but I haven't tried to yet>Use high quality tracing paper, transparencies never work very well.Transparencies work if you use an inkjet printer with pigment ink, tracing paper if you have a cheap laser printer and expose the print to paint thinner vapor
>>1612063i don't, it's funyou just might not be autistic enough
>>1611970Imagine ending up in the past and you need to build a time machine. You know exactly what the circuitry is supposed to do but there are no microcontrollers yet, only TO92 transistors and other discrete components. By the time you finish you're alreadt 92 years old and the time machine is working, but there's no point in using it because you're already dying of organ failure, and everyone else thinks you're just a nutjob.Years later someone comes up across your time machine, manages to reverse-engineer it, invents a time machine that looks oddly similar to the one you used to go into the past and tests it, only to become stuck in an era where no time machine was available.
>>161185716V AC usually means 16V RMS, so multiply by √2 to get the peak = 22.6V. Then subtract 2 diode drops (~0.65V each for silicon, less for Schottky) = 21.3V.If you plan on dropping that to 3.3V, you need to drop 18V. With a linear regulator, that means wasting 5.5x as much as you're using. And a resistor isn't an option; A 10% change in current draw translates to a 55% change in voltage. If the AC supply is several amps and you only need a few mA, a linear regulator will suffice. Otherwise you need a switching regulator (buck converter).
>>1612067you got a point thereCan we have a webm of this baby functioning?
>>1611869The theory is written in terms of integrals and derivatives. Originally, PID controllers were analogue devices (first mechanical, then electronic). In DSP, the derivative becomes the difference between samples, the integral is the accumulated sum of samples.(The derivative may be low-pass filtered to remove noise, which typically means using a weighted sum rather than just x[n]-x[n-1]).The various terms can be combined into an IIR filter (the integral term can't be implemented in a FIR filter), so y[n]=(weighted sum of x[...n] and y[...n-1]). Integration is just a basic IIR filter: y[n]=y[n-1]+x[n], and the proportional term is just x[n].Also: practical implementations usually have some mechanism to prevent integrator wind-up (if it takes a while to reach the setpoint, the integral term gets large and the system takes a long time to stabilise), e.g. clamping the integral term to fixed bounds and/or disabling integration while the output is saturated.
>>1612076where "samples" are actually the error, the difference between the set value and the process value
>>1612081Maybe. The derivative term may use the derivative of the process variable rather than the error so that you don't get a spike when changing the setpoint.Using the derivative of the error is preferred if the setpoint changes continually but slowly. Using the derivative of the process variable is preferred if the setpoint has occasional sudden changes.
>>1610799Wanted to follow up with this. Anon was Right, I replaced the Relays with new ones (Hard to do since those ones were old af and the old pin outs dimensions were so large) and it's working flawlessly. For $40 Cad (30Usd) 20V & 5A is pretty good.
>>1612073how do i into webmrecord mp4 and handbrake it?i'll do it on monday probably, not at home rn>>1612069>not travelling back in time and cumming into the primordial ooze
>>1612091if you do that, the corvids will have become the apex intelligent life form
>>1612058>Will the core accept more copper (both in terms of space available and saturation flux)?I haven't disassemble the thing yet (since I can't find fucking torx with a hole anywhere), but judging from pics from internet looks like I can add couple turns no problem.Saturation flux - I don't know. Is there any formula that will allow me to calculate it, knowing geometry (cross section) and material? Also, I don't know much about transformers and motors, but I wound couple transformers in the past using this formula S=1.2 sqrt(P), where S is section of iron core (cm), and P is power, but I think it is very very approximate thing, which is only valid for 50 Hz 220V mains. Shit worked fine though. >Flux is proportional to turns and currentRight. Either you increase current (which is problematic, since battery trips at 25A, which is already too much for this motor, which was designed only for 15A), either increase number of turns (which is also pain in the ass, but at least copper is cheaper than batteries and new controller). >so using fewer turns of thicker wire (or more turns of thinner wire) doesn't change anything (double the turns, half the cross-sectional area of the wire => half the current, double the resistance, same flux, same voltage drop from resistance, half the I^2R losses). Although inductance increases with the square of the number of turns, so you need a higher voltage for a given speed in spite of the lower current.Yes. I give zero fuck about speed (actually no, but I may trade 5-7 km/h from top speed).So, what should I read, so I can increase number of turns knowing what I'm doing?Can I 2-3 solid thick wires instead of 6-8 thin wires?
wait a minutethe cheap bench power supplies have both a voltage and current adjustment in picturesI though current was determined by the resistance and voltage and therefore couldn't be independently adjusted while maintaining constant voltage
>>1612130They maintain constant voltage until the set current limit is hit, then they lower the output voltage.
>>1612133Okay that makes more sense.If I ever get one of those hopefully it comes with a manual
>>1611844I can see that's a Y safety gondola (y tho)gondola QFN? (yeah no legs)
>>1612000>the / keythank>>1612172it's just a generic ceramic
>>1611725>>1611727oh I've been to a shitty college. they ditched the decent analog scopes and replaced them with bottom-shelf digital ones. This was widely regarded as a bad move, but nobody dared to say that out loud.
>>1612193We've got 4-channel USB digital scopes for half the lab computers but even in 3rd year labs we never used them. Probably because I looked up their price tag and it was something around 10k. We also have some normal 4-channel digital scopes, which are a bit of a pain to use but seem to work just fine. Can't remember their brand name or price however, and there aren't that many so I usually end up using a Hitachi analog scope. All our DMMs are brand name Flukes or Hiokis too.
>>1612193Freshman here. How do I steal equipment from university? >inb4: Tyrone.
>>1612207I know people that stole oscilloscopes, but they won't share the secret.Do I blow this up, wait for them to trash it, and pick it from trash and repair?
>>1612205I stole an old spectrum analyzer once. I told the lab supervisor it wasn't working, he told me to go throw it in the dumpster. I went and threw it in my car. I didn't expect them to be so apathetic about that but they were. but really, make friends, make sure the lab people know your name and you'll have first pick of any stuff they're getting rid of. If you spend a lot of time in the labs, helping keep the place neat and organized will earn you a LOT of brownie points and they can be more easily persuaded to get rid of things you want.
>>1612220>Do I blow this up, wait for them to trash it, and pick it from trash and repair?It can be incredibly hard to repair an oscilloscope.
>tfw likely fried an opamp soldering it to the boardF U C K
>>1612226>I stole an old spectrum analyzer once. I told the lab supervisor it wasn't working, he told me to go throw it in the dumpster. I went and threw it in my car. I didn't expect them to be so apathetic about that but they were.Lol.>but really, make friends, make sure the lab people know your name and you'll have first pick of any stuff they're getting rid of. >If you spend a lot of time in the labs, helping keep the place neat and organized will earn you a LOT of brownie points and they can be more easily persuaded to get rid of things you want.Well, I need to survive until labs first...But yeah, common sense. I got couple school PCs and printers like that. >>1612235I know, so it would be pretty difficult.Okay, but what about electronic components? Is it ethical to put them into pocket and stuff?
>>1612242>I need to survive until labs first...noif you want to do a project, do one. When I was a freshman I rebuilt an amplifier, asked around and they let me have lab access to do that project. If you want to make connections, doing a DIY project as a younger student is a great way to do that. If your school has a shred of decency, your EE professors will wildly approve of electronics hobbyists who want to learn. If you do that you'll hardly even have to steal, you can get a lot just by asking.
Also my RGB LED strip I've been using for lighting keeps changing color when I'm not touching the remote, and it happens when there's no battery in the remote either. It's a radio remote instead of an IR remote, so I imagine some other RF remote or device is accidentally sending my lights signals. I tried covering the inline receiver with alfoil but it isn't working. Just tried grounding the foil now, but my remote's signal still gets through.>>1612240>he doesn't use IC sockets
>>1612264>It's a radio remotethat was your first mistake
>>1612270Not like ali had an option for it on that listing. I never intended on using it for lighting this often either, otherwise I wouldn't have gotten something with such poor colour rendition. Ideally I'd have a 6000K and a 2000K LED COB both running off constant current supplies that I can change the current of individually. Maybe a red COB too just for that edgy factor, especially as a ring light around the other COBs so everything gets a red outline in their shadow.
>>1612242Is it ethical? No. Did it stop me from pocketing a bunch of JFETs during one of my labs because JFETs are stupid expensive? No.
Is it possible to get neon tubes for cheap? Custom designs I'm assuming would be expensive but what about a couple of straight segments or just simple shapes? No signs. Just some basic neon lighting. ACTUAL NEON PLEASE. Not that fake neon shit with an LED strip and a diffuser. Not EL wire. Not cold cathode lamps. Proper Neon tubes (or argon, xenon, etc. you get my point).
>>1612390Well for starters they're not exactly bendable, so for most applications they're useless because people tend to buy neon tubes for the purpose of having custom shapes as made by the manufacturer to order.Secondly, they're not exactly durable, so even if you found some unwanted ex-soviet stock in Ukraine you'd need to pay out your arse to get them shipped.Thirdly, they're a pain to drive, meaning the market for them has dropped as LEDs and other much simpler lighting methods have turned up. That doesn't mean there isn't any market for it, but it does imply that it will be a fairly niche market that only hipster club managers enter, so I'd not be too hopeful about getting anything affordable. I'd check out your local junk shop to see if they have anything that suits your requirements. Small gas tubes (H, He, Ne, Ar, Hg, etc.) are still made for science demonstrations and may come with their own driving circuits, and could be tolerably priced from the right supplier, but they won't exactly be good for lighting.Another thought is going for a (laser) flash lamp tube, which might be possible to drive continuously with some sort of constant-current driver.
I did it!It's fucking beautiful.No hand melting with acetoneNo sharpie fixing of crappy laser tonner transfer No ironing, no nothing.Perfect coverage ready for etching.I can even just swap the sharpie for a white one and add a fancy silk screen if i wanted to, but fuck that
>>1612390Nope. The only reason anyone uses neon (and similar) is that it's relatively straightforward to make shapes to order. If you don't need that feature, it's expensive, fragile, unreliable, and dangerous, which is why no-one bothers making off-the-shelf neon tubes.
>>1612496looks pretty crappy desuproper photoresist or toner transfer would have produced a much better result
>>1612500Sour grapes eh?There are no flaws in the traces at all, if i etch this the pcb will perform flawlessly.If i wanted even better results I could use even thinner pen and perform poly bed leveling on the pcb with the probe, but this turned out so well I don't need to do any of that stuff.This is so much faster and more convenient than the shitty toner transfer methods i tried before (both hot and cold ones) that this is not even a competition.
>>1612503>There are no flaws in the traces at all, if i etch this the pcb will perform flawlessly.maybe it's the poor photo but every corner looks fucked to meits good enough here because it's all big traces but for small SMD stuff (which is where you really want etched PCBs - your pcb could be done on a veroboard in 5 minutes) it's not gonna be good enough>This is so much faster and more convenient than the shitty toner transfer methods i tried before (both hot and cold ones)should have used photoresist instead - toner transfer takes more fucking around at first - but is very quick once you developed a good processsome people even modified their laser printers to print on a pcb directly
>>1612512Photoresist is pricey, since you need the transprent foils to print on, then to develop it and whatnot, plus the photoresist pcbs cost a bundle compared to regular ones.I would go for such solutions if i needed such fine detail, but none of my circuits will be so small where i wouldn't be able to use my super simple process of >printer paints artwork>printer optionally drills tht holes>toss into fecl3done
>>1612521why not mill directly then?etching is pointless if you don't need the detail
>>1612522>why not mill directly thenthere are several reasons why drawing and etching the board is better for me rather than milling it.I don't really want to write an essay on all the reasons here, but if you want to know you can watch some pcb milling tutorials on youtube
>>1612496>right in the middle of the blank PCBGreat work but that's a little wasteful.
>>1612532We live in times of plenty, enjoy it
>>1612358I have noticed that literally all EE students have sticky hands. Why?
>>1611970lol that's nice
>>1612521>Photoresist is pricey, since you need the transprent foils to print on, then to develop it and whatnot, plus the photoresist pcbs cost a bundle compared to regular ones.None of this is correct. Transparencies are pretty cheap and reusable and as mentioned above you can use tracing paper. The boards with photoresist already applied are not much more expensive than boards without and you can buy the damn paint and apply it yourself anyway. Even the UV boxes are not expensive. Etching the boards can be fairly expensive though.
>>1612551>Etching the boards can be fairly expensive though.FeCl3 is cheap
>>1612557a true cuck only uses cucl to save the environment
>>1612567Can be made cheaply with HCl
>>1612557I make up my own Edinburgh etch solution, and it's the other equipment that's expensive. I have my own sooper sekrit methods for the etching bath that's cheap and really good but not volume friendly, but standard equipment like a bubble etch bath costs, at least relative to everything else besides maybe the printer. Yeah you can use a tray or whatever but not always.
>>1612567And copper chloride is super useful in making high precision boards, though I'm not totally happy with my process thus far.
>>1612496Final version.I am going to try to test etch it now, wish me luck.The infill has a bit of a pattern, i hope i is covered enough. Otherwise i will have to do larger overlap.But holy shit, watching that sharpie moving around drawing the schema bit by bit is incredibly satisfying.
>>1612584Has anyone ever tried to just print directly on the PCB with an acid-resistant plastic like PETG?
>>1612586I considered it but the detail is not good enoughSharpie is no harder than normal printing and the result is much betterplus with a plastic layer it would be superhard to sponge etch
>>16125940.1 nozzle would beat a sharpie easily
>>1612596but i am not going to change nozzles every time i want to make a pcb
>>1612584okay, first attempt turned out to be MEHi think i rubbed too hard with the sponge and i managed to wipe off some of the sharpiethe infill pattern left some holes too as i assumed, i have to increase the overlap between sharpie lines
>>1612599Welp, i tried to beep it and all contacts work flawlessly, so thats nice.I'll try to solder it to see how well i can do it without a mask.
>>1612521>you need the transprent foils to print onbut you don't. you just need a blue laser pointer with a respectably small aperture so you can swap out your current sharpie with it>to develop it1% washing soda soln, straight from the supermarket. it's $6 for a 2kg box here>>1612598then don't, just let your G-code work its serpentine path over your ground fill
>>1612540seems like the only major where the tools to create are semi-cheap but simultaneously not marketed towards individuals and can be ridiculously expensive or over-priced.>an EE student with sticky hands for an altera FPGA, there was a cabinet filled with 50-100 oops
>>1612695You can get cheap FPGAs
Batteries are electronics.I found a lead paperweight, 6V 12 AH.How can I recover it?
>>1612720yeah I wasn't justifying my own theft for that reason. Though the 'cyclone' has a shitton of nice peripherals that wont come cheapbut i meant to mention also that EE as a profession and hobby goes hand in hand, so seems like wanting to own the items would explain stealing
>>1612730glad to see you read /ohm/ RULE 0keep going and read /ohm/ RULE 1
>Optocoupler : digital signal like PWM pulse >Isolation amplifier : analog signal such as sinusoidal Did I get it right??
>>1612788Oh, I found.>>I have junk, what do?>Take it to the recycler.
>>1612840but did you even google>>1612839yes
>>1612839nope. you can use optocouplers to send analog signals. use a DC voltage to bias the LED on, then AC couple your signal on top of that. a vintage gadget called a vactrol was often used for this purpose.
>>1612847I googled. People say that I should try adding water there. Idk, it doesn't take charge. Even with water.WHat is really cool, is that it had a fucking negative pressure inside.
>>1612849normal opto coupler works too
>>1612849Wasn't a vactrol made with an LDR?
>>1612877true but irrelevant. wikipedia's article explains the vactrol in more detail than anyone could possibly need, with 87 footnotes in case you want more.
Newfag here, Is it possible to replace the batteries in pic related? I know they don't sell official replacements, but couldn't you replace it with a generic battery of similar voltage?
>>1612911>but couldn't you replace it with a generic battery of similar voltageCertainly. They probably use a dozen 18650 cells of some specification or another. Take it apart and see what you're working with. Ideally there would be lettering on each cell that would direct you to a datasheet of some kind.
>>1612911There might be a third party one available, but if there isn't, you can score the seams on the battery with a hobby knife, and then see if there are 18650 cells. You could then probably replace them no problem, since I doubt that they'd bother putting in a circuit that can tell if the cells have been replaced.
My sensor circuit has 3.2V output ,but it's 26Vp-p floating above PE in AC domain Should I connect it to GPIO of MCU???
>>1613027Just give them both a common -ve reference first, chances are it's just floating up thanks to mains capacitively coupling to some part of your circuit. An open-collector of a FET could also potentially float up that high if they are already tied together, so an external pullup could help keep things constrained within your rails.Just slapping them together without this shouldn't have any adverse effects, but I'd say it's good practice to connect them all to a common -ve rail before proceeding.And what the fuck is PE supposed to mean
>>1613038>but I'd say it's good practice to connect them all to a common -ve rail before proceeding.What about floating my MCU with power bank?>what the fuck is PE supposed to meanProtective Earth
>>1613044>What about floating my MCU with power bank?Just connect the 0V rail of your sensor circuit to the 0V rail of your MCU to the 0V rail of your power bank. Then measure between the sensor/Vcc pins on either device.
>>1613038What is -ve supposed to mean? Is there also a +ve?
>>1613091-ve = negative+ve = positive
What is the best way to switch between two powersources? I have one that is always 3v and one that is 3-5v i want to use the 3-5 but only if it is below 3.5v otherwise use the 3v.Is two mosfets superglued together the best solution? Currents 0.5a tops
>>1612240Nevermind. Some chucklefuck left one of the channels on the oscilloscope to 100X and I being a bigger chucklefuck didn't bother to check. Good thing I went and double checked with a multimiter before trying to desolder the whole IC.
>>1613099Both relative to a common 0V aka GND, so a dual supply?
>>1613111Well when I said -ve I was referring to the 0V rail, because I assumed you weren't using a dual supply.
>watch someone on youtube solder smds>he puts solder on his iron tip>gently touches the smd>perfect amount of solder flows to the smds, the smd centers itself and is flawlessly soldered to place>take the iron and put a bit of solder on tip>touch the smd>solder covers every single pad and trace as far as eye can see without even an of it ending up on the smdfucking assholes, they never mention they used CGI in those tutorials and soldering smds in real life is impossible
>>1613134>he puts solder on his iron tipnever do that unless you pre-tinned the pads or use extra flux
>>1613136>solder on his iron tip>use extra fluxThis is entirely how I solder anything, SMT or THT.
>>1613139what flux do you use?i asked in electronics stores here for the flux gel thing and none of them sell them and on the internet i see them at outrageous prices with like 10 milliliters going for $20
>>1613141Rosin flux paste in a tub. Bought it for probably more than I should have at jaycar, but it's lasted my years so I can't complain.
>>1613145This?Can is it gelatinous enough where i can apply it with a syringe? Also does it have an expiration date? i don't want it to turn into a rock after a year
Total beginner here hoping to build a theremin. I read through Mims' Getting Started With Electronics in the OP but still don't really understand how to read a circuit diagram like pic related (schematic for a theremin). I'm wondering if one of the other books in the OP would be better for me to read through and maybe if someone could just give me a quick rundown on what I'm going to need/how to get started.
>>1613146No expiration date as far as I know. The stuff I have is transparent, probably just rosin in some sort of solvent to make it semi-liquid at room temperature, and it's really easy to apply. A bit too thick to use a syringe with, but a popsicle stick would spread it wonderfully with little force. The stuff in your picture looks harder and and opaque and it may not be rosin, since the "No ..." at the bottom might say no-clean. Getting no-clean flux might be the way to go, since after slathering your board in rosin you have to slather it in IPA to get rid of it again, but from what I've experienced from those no-clean flux pens, the flux isn't nearly as effective. A concentrated flux paste might be different to whatever is in that pen's solution however.
>>1613160Well the smds i am using are no smaller than sot23 so i can spread it with a stickdidn't know fluxes were clean and noclean, i will definitely buy a noclean then since i'm lazy, does the more watery one have some special designation?
>>1613170>does the more watery one have some special designation?liquid
>>1613172Well the store i use has pretty much only this, it is pure rosin and pretty cheap too, only two bucks so i am going to try iti don't have a heat gun, so i hope i can just smear it on and stick my iron into it
>>1613176You can dissolve it in alcohol
>>1613176>pure rosinWon't that be solid? Not like you can't dissolve it in white spirits or something and make up your own paste, which is probably something I should attempt. Actually my pine deck has a bunch of resin leaking out of the handrail, and slicing off some of this I found I could get it to work as a flux without issue.
>>1613185Should be pretty easy. I will just toss some into a wider syringe, with some ethanol and make my own flux pasteif it doesn't work it's so cheap it doesn't matter
Building this guitar effect and trying to understand it. Some versions of the schematic omit the 10k R14 resistor as pictured here. Any clue as to what it's for?
>>161319110k are usually pulls downs or pull ups
>>1613191R14 modifies the (low) cut-off frequency of the high pass filter formed by C13 and whatever comes east of it. You may not notice the effect at all.
>>1613157It should be explained in the book, don't expect a shortcut. Did you get the principle behind the Theremin organ, the two oscillators and the mixer?
>>16130500V of my sensor also float too
are there any dip photointerrupters that work with 5v microcontrollers without requiring an analog pin to read their values or associated comparator circuits?
ordered some nice stm32s and IRs (along with the tc100 miniware iron) Gonna do some lap + sector timing counts for mini4wd tracks (or anything really, it is generic).
>>1613262that costs almost as much as a new ts100
>>1613264and that's a good thing, it's a pure american made productthe best flux you will ever use, it is usually only sold in bulk to companies but was made special thanks to rossmann
>>1611834Made me laugh out loud - I prefer this version without the number
>>1613269With the amount of soldering i do, i just cannot justify such a massive purchase when i can make similar goo myself by dissolving rosin in ethanol and get the same amount of goo for like 50 cents
>>1613262Showing 1-8 of 50 reviews...
>>1612999>>1612925>>1612911Ok, just took the vaccuum apart and fond out that these are nickel-cadmium, not lithium. Anything I should know about these?
>>1613258You can use a digital pin. If you want some more robustness, and an is buffer / not gate with hysteresis.>>1613313NiCads are absolute horseshit. It'd be easier to buy a battery and charger, and wire yourself a holster to make the battery go in.NiCads barely last a year or two, I'm lmao'ing that even fucking Dyson uses NiCads. I think NiMH might be compatible with NiCad charging circuits (current based that trickles off above about 1.2 * pack voltage)Also, never smell an exploded NiCad pack. Enjoy ur heavy metal poisoning.
>>1613330nvm, your vacuum wasn't Dyson. I was looking at the glowy purple bits, I'm surprised they were able to get out of a trademark infringement because Dyson is characteristically a translucent purple and soft gray.
>>1613104>if it is belowa slightly unusual application, but oka comparator or two + a pair of p-ch MOSFETs ought to do it. choose comparator for low power and push-pull outputs, choose MOSFETs for low Rds(on) and low Vgs(th), the AO3401 would be great if you don't mind a SOT-23>>1613258why would you be using an analog pin instead of a digital pin with Schmitt trigger?>>1613330>NiCads barely last a year or tworeally now? I have a beard trimmer which has lasted almost 20 years and hasn't experienced a significant reduction in capacity to notice. still original pack. you just have to maintain them, with the full-drain and recharge cycle
>>1613191it's an optional safety device. the 10K makes sure there's little or no DC voltage going to the pot. in this way, if the pot is temporarily disconnected by vibration, or whatever, you wont get a loud DC pop that could blow a speaker.
Can anyone here translate this meme to me, because I don't get it.
>>1613396top: sophisticated soviet engineering to extract truth from dissidents.bottom: simplistic american pig dog engineering to extract truth from sand-niggers.
daily reminder that the commonly-seen NC-559 and RMA-223 fluxes are designed for leaded alloys only. this one otoh is universal https://amtechdirect.com/product/amtech-vs-213-a-tf-tacky-solder-flux/>>1613396>The original scheme of the device "electric">Circuit modified by our reader
>>1613401Kek>>1613402>The original scheme of the device "electric"Wtf is "electic". Seems incomplete.
>>1613405you're absolutely right. it's "electrosleep" kek
>>1613411Kek. Second one is better, it provides better sleeping action.
>>1613416too good for most people, who should start with the original and work their way up
>>1613269>and that's a good thing, it's a pure american made productFuck off with that nonsense. Where can I get the Chinese version for 1/10th the price?
>>1613257float with respect to what?>>1613274here's a shaded version for you>>1613313uh, didn't your photo say "lithium" on it
>>1613402>leaded alloys onlyWow what the fuck, no wonder my flux pen wasn't doing the business. I guess I'll stick to rosin for now.Anyone know about that tube of flux that Louis Rossman uses, and if that's suitable for Pb-free or not? He uses it to repair motherboards so I'm assuming he's also using Pb-free solder paste, but I can't find Pb-free solder paste on ali at all so perhaps he just repairs people's computers with 60/40.
>>1613654If you drew that gondola cap I fucking love you
>>1613672I drew this one a while back too
>>1613675This is why I'm stuck here forever
>>1613402My flux of choice is plumbing flux, since I deal with third grade corroded salvaged shit all the time.Water and alcohol soluble. But for BGA I would use no-clean shit.
>>1613654It turns out I had a different, but very similar vaccuum compared to the one in the original pic I posted.
>>1613146personally, when I am in a restaurant, when I remember, I just grab a wooden toothpick at the cashier station, and dab paste flux with that. also good for holding mid-sized SMT components in place while soldering>>1613134so many variables, but one might be the wrong size of solder wire. the smaller the wire, the smaller the droplet you can put on a tip>>1613671the ones on Louis's site are all leaded>perhaps he just repairs people's computers with 60/40.yes. he doesn't have to prove anything to anyone much less file paperwork over it. SAC305 and 60/40 can be mixed without any detriment to the quality of the joint
I've got an old icom transceiver, like 30 years old. I was talking on it, and smoke started coming out of the PA section. Now it only puts out like 2 watts of output power instead of 100. How do I troubleshoot something like this? Nothing is obviously burned looking on the PA board.
>>1613736>the ones on Louis's site are all leadedThen what do they use for hand soldering in industry? I assume all their reflowing flux comes inside the solder paste itself.>>1613737Smoke sounds like it came from a transformer or inductor, (balun?) check those first. Could be a power resistor also. Assuming there aren't any visible shitstains on the board or on components of course. Checking the state of your electrolytics is also a good practice, since arguably dead electrolytics could have been the cause of some other part letting out smoke.
>>1613740>Then what do they use for hand soldering in industrylead-free solders, as regulations require, with a flux designed for lead-free soldering. plenty of options in the market
>>1613737why does C22 look so hit up?assuming you have tested all the transistors and verified none of them have blown short, when in doubt:acquire or draw a schematicapply dummy load, keyfollow signal through circuit with probe, plot voltages on schematicfind the part that isn't producing an output consistent with its inputs
>>1613753Is that true, that all lead-free fluxes are acidic and needs to be washed off?
>>1613758not at all, there are all kinds of no-clean fluxes for lead free solder
>>1610590What are some good electronic chain stores that sell electronic components? All i know of is radioshack i think and the one in my town closed down years ago. Just wanting to do some little projects in my spare time but have no idea where to get any parts other than online
>>1613759yes but what do they sell these as on ali
>>1613763if you live in a medium-sized US city, you may have a brick and mortar independent components retailer where you can do so, but those seem to be fading away as well. a major chain computer store may have a components section (Fry's used to, might still) or at least a maker section (Micro Center). with Digi-Key having all sorts of shipping options from First Class Mail® on up, no small order service charge, and no minimum order, it doesn't make a whole lot of sense to go to some local shop and end up paying $1.49 for a 555I can definitely vouch for the practice of buying a reasonable variety of electronics stocks on alibay as specifically suits your interest, so that you have a reasonably good chance of having components to hand that will work for your application>>1613776I don't... know. for a first attempt I'd search for lead-free flux and ignore any ad that mentions 223 or 559 because they're likely fakes. then ignore the leaded fluxes and pastes that ali helpfully put into my results, and after a few pages find ten or twelve ads worth a second look
>>1613759Is rosin dissolved in ethanol noclean?
>>1613788Yes and no
>>1613783Searching for "lead free" just comes up with leaded, at least as far as solder paste goes.Looking for flux paste in particular I'm seeing a bunch of 559 syringes/tubes, but that's a smaller volume than I'd want anyhow. But I am finding some Sn-Bi solder paste, which I didn't expect ali to have. I wonder what that's like to solder with.
Ok so I tried some of the M0.9*2.5 PCB rivets and they worked ok, but I did run into a few issues.Firstly, they were a pain to rivet properly, frequently my punch would wander off to one side slightly and flatten the rivet asymmetrically. Perhaps 1/2 of the riveting attempts worked properly. From what I've seen online this can be amended with the proper riveting tool, which has a solid core to keep the inner rivet open, but I've yet to find one of these on ali. In any case, the punches I was using (an automatic centre punch and a normal hammer punch) had a pretty broad tip, where I think a much narrower tip (~60° to the normal) would help instead. I think the slow increasing pressure from the auto-punch didn't exactly help when it came to the rivet slipping sideways.Secondly, they say 0.9mm but I had to use my 1.0mm carbide drill instead since the rivets did not fit in the 0.9mm holes. Possibly the rivets are to spec and the fibres in the FR-4 were just pushing outwards into the hole, I don't know. Anyhow I ended up snapping the carbide drill so RIP that testing.Thirdly, for the gauge of 2-sided copperclad I was using, the rivets appeared to be a bit too short, so I'll likely buy the M0.9*3 ones next. I tried punching the copper itself in a little to make room for either end of the rivet and see if I can get a reasonable amount of the end flattened on the other side, but since at this point I was using the 1.1mm carbide drill, the results weren't stellar and the things still kept going off to one side.So I'll want to track down some better punches (getting anything other than an auto-punch from ali is tough), buy some new drill bits, and buy those longer rivets.
>>1613790so yes then? goodit makes sense since rosin shouldn't be corosive when it's cooled downi just want something i can ejaculate over the contacts, solder it and then just leave it there
>>1613797why don't you want lead solder?It's the best, it beats lead free solder in every single aspect except enviromental crap.I have a sn-pb solder with a flux core and it solders amazingly even on corroded stuff
>>1613807Because I don't find lead-free hard to solder with at all, I barely notice a difference between it and 60/40. I use it because I thought there wouldn't really be a downside, especially if they stop making 60/40 and other leaded alloys. Of course the price is higher, but being able to hold a part in my mouth or not having to wash my hands after handling stuff is just worth that in my opinion. I've seen the infographics on lead having an impact on IQ and I guess they had an impact on me.But all I've seen is a surprising amount of equipment for leaded soldering, so much so that I'm starting to suspect that cheap electronics don't use the RoHS stuff. The fact that normal no-clean flux doesn't work well for lead-free took me completely by surprise.
>>1613811unless you live in ancient rome, just holding the solder with a small amount of lead in it in your arm won't do anything noticeable ..you.. don't eat it, do you?
>>1613814Who needs a third hand when you have a mouth?Anyhow I mainly moved to lead-free because I expected to have more options as to the accessories I used, not less.
>>1613816industry hates the lead free solder, corps only use it because government forces them even big pcb making houses still struggle with lead free solder during manufacturinga hobbyist should never touch that shit
>>1613817I might swap back then. I still have a reel of the leaded stuff somewhere.
>>1613807>beats lead free solder..Of course. The Grey Tin problem of lead-free soldering persists and the mil/med/sci sector is still exempt from the RoHS directive which only addresses industrial mass production, not the small scale use of 60/40. The introduction of lead-free Green Meme soldering products for the hobby market was a successful marketing psyop that created the Cult of Flux we see here in action.
>>1613827I've certainly heard of tin pest, but I doubt I'll ever see it on any PCB I make or buy. It's just too rare, unless your PCB is routinely subjected to particularly cold temperatures.
>>1613349>a slightly unusual application, but okwell i need to power a device that takes 3.3V (to about 3.7) only but the source voltage can be 3 - 5V, i of course have ldo regulator to handle 4V and above, but the spec sheet says than it needs about the 3.9v to work correctly, so once the supply drops below 3.9V i need to bypass the regulator and feed the device directly it's the best solution i came up with since they don't make any ldos that have like 200mv dropout, can supply up to .5A and aren't some incredibly exotic shitty tiny smd thing
Reminder medical and aerospace equipment only use 60/40 solders. Leadfree simply doesn’t work as well
>>1613201>>1613379>>1613516Thanks, but that doesn't make it much clearer. So it can be a pull down, part of a high pass filter, and also modify the taper of the volume pot?
If I have a linear regulator that claims a output current of 1.5A min, 2.2 may and I only need μA, as long as the Voltage is as intended for a IC, will I fry my circuit?
>>1613878resistors can be used for many things.
>>1613896and sometimes they can be omitted.
>>1613802Ok the only proper punch tools I can find on ebay are like $70 for a pack of 5 from a name-brand, and these are the ones that videos/tutorials of hobbyists use, so it seems there aren't any chink-made versions. But I figure I can use a bolt with the right size shaft as a punch that will keep the hole open, or even cheaper, a piece of thick acrylic with a hole in the middle sized to fit a nice thick diode lead. So I'll make that thing in the laser cutter tomorrow and see what kind of result I get.>>1613878It's the middle one, since it's in parallel with the volume pot I don't think it affects its linearity at all. But the volume pot already makes a high-pass filter, so I assume it just makes the cutoff frequency slightly higher. It's not like the potentiometer's resistance will be much over 10k anyhow. It's definitely not a pulldown unless you count a parallel resistor of a filter to be an "analog pulldown".
>>1613926Volume pot is 100K
>>1613934Well in that case it's fairly significant I guess. What's the capacitance of the electrolytic C13?
>>1613687Patrician. Shit is cheap (ZnCl2 stuff), solders good, and 50/50 solder is good too, less fragile, than 60/40 or 63/37.
>>1613935Two versions: C13=10µ R14=10K and C13=1µ R14 omitted. This is what the first reply hinted at.
>>1613191What's the purpose of D2 and D3 in this circuit?
>>1613687Do you clean the shit up thoroughly afterwards?That stuff will eat through the copper traces.
>>1613968Yes, since it is conductive.
>>1613956signal clipping, fuzz
>>1613740>>1613757Thanks bros, buying an oscilliscope on ebay today, have a schematic, and will go through bit by bit.
Can I make a breathing LED light with discrete parts or do I need a microcontroller?
>>1613987Don't need a MCU
>>1613987without a micro you'll probably get a linear up-down fade which looks completely different from breathing. with a micro, you can shape the effect precisely using a table of brightness values. and you can use multiple tables for panting, sleeping, yogi-ish, dog-ish, hyperventilation, ataxic, dying, orgasming, adolescent heavy-breathing prank call, etc.
>>1613797how much did you want?https://www.aliexpress.com/item/10pcs-lot-MECHANIC-F913-Lead-free-Benis-Reballing-Flux-Solder-Soldering-For-Professional-IPhone-IC-Chip-Benis/32994095126.html>>1613805it's the activators that might be corrosive. if you were to throw a touch of hydrohalide acid into it you would want to wash afterwardalso, plain rosin flux residue might be sticky to the touch and attract dust etc.>>1613811shouldn't have been a surprise, since lead is in column IVb of the periodic table and silver is in some odd-numbered column of tranny metals. their oxides would react to potential flux materials rather differently>>1613827>cult of flux500 joule kek>>1613854how about a buck-boost converter? I think you can use the MC34063 to make one of those but I haven't finished my coffee yet>>1613881that's a max output current of 1.5A min before it does max output current things like folding backif there is a minimum output current, it will be stated in the datasheet and is probably on the order of mA>>1613978sheeit, a voltmeter would have been enough to get started>>1613687weird flux but ok
>>1614033Thanks for the reply. So if I adjust the voltage correctly for the esp8266 and hook it up to the AC/DC regulator, I won't fry it?
https://yarchive.net/metal/soldering_flux.html -- about acid, read the whole textShort excerpt for the fluxophiles:"If you need some extra rosin flux, go to a music store and buy a block of rosin like those used by violin players. Ask for the oldest, dried-out block which should make the store owner happy (the musicians prefer the soft, sticky ones). Dissolve as much of this as you can in a small glass bottle containing acetone. Remember acetone is VERY flammable. But it evaporates quickly leaving the rosin behind, ready for soldering. One block will normally last a lifetime."
>>1614069Thing is, rosin in those places is expensive, even stuff they will throw away (hint). Where can I buy rosin cheap? When I lived in soviet shithole, it was literally sold in auchan. And where can I find borax?Also I miss ЛTИ-120 flux. Westerners are stupid to make flux this good.
My open-drain output PWM has huge DC offset What cause this?
>>1614076Everywhere?Even Amazon has cheap rosin.And there's Ali/ebay that will ship to any shit hole.
>>1614090Won't customs think this is a weed of sort?
>>1614108How do you mistake solid rosin flux for a weed?It's unlikely customs will even open the package. There's way too many packages to check.
>>1614111>How do you mistake solid rosin flux for a weed?Organic subtance. Meth, idk. I honestly need rosin only for aroma, shit produces nice fumes, effective against houseflies and effective from getting older than 60 y.o.
>>1614069Difficult to get good acetone in a lot of places now, too many surfactants/additives.
>>1614124You can use ethanol.I takes a while to dissolve in it (a whole block needs a few days) but it works.
>>1614032>anon deleted post to add orgasmingthis is why I'm here forever>>1614076>boraxyou might find it stocked by the laundry additives or home cleaning products. may also have it at welding supply or pottery supply>>1614062correct. looks like some rando on hackaday said that the 34063 will work* in damn near any topology, including SEPIC. but if you're interested in efficiency, which you might be if supplying from a battery, shitty tiny SMD is where the action is. all about SEPIC herehttp://www.ti.com/lit/an/slyt309/slyt309.pdf*inefficiently and slowly but will deliver>>1614086show schematic of OD output and whatever is connected to it
>>1614032I ask because I need to fit the circuit in a 4x4x2 cm box and I don't know how much I can stuff in there besides a 555 timer and a few passive components.
>>1614133>100 ohm pull-upI need current to drive optocoupler50Hz PWM 50% duty cycle
>>1614076>Also I miss ЛTИ-120 flux. Westerners are stupid to make flux this good.>Pine rosin 25%, ethyl alcohol, triethanolamine 1-2%, diethylamine hydrochloride 3-5%Dont use that shit. It's corrosive, hygroscopic and hard to clean. It is good only for large dirty copper wires.
>>1614134 Arduino Pro Micro is only 33x18mm
>>1614142perhaps your comparator isn't happy trying to sink 30mA?>ultra low power low voltage comparator>pic relatedyup, you need a stronger driver. maybe an 'LVC1G14 or '1G17?
>>1614124Fucking junkies. In my shithole they had banned ethanol. This made me anarchist.
>>1614152What? Do you live in a Muslim country something?
>>1614152 Pay your alcohol taxes Ivan.
>>1614154I used to live in Russia. Yeah, you could buy 95% ethanol, but now only IPA. >>1614155First, I'm moved to shithole where you can buy ethanol in fucking walmart. Second, no. Booze must be tax free.
>>1614150Excellent, thanks. Will investgate.
>>1614134>how much stuff can I fit in a 4x4x2cm boxone deep, with proper courtyard, about 520 resistors before a stereo microscope becomes a very good idea :^)>>1614152>banned ethanolthe USA tried that once. didn't work out so well>>1614157>from high-grade everclear>to India Pale Aleпyтин нeт!
>>1614151ahh i get it even r1k (3.3mA) it still has mini offset .Thank, anon
>>1614168>the USA tried that once. didn't work out so wellRussia too, but it didn't work well too. Instead of drunk gopniks, they got blind drunk gopniks, since they were drinking brake fluid (soviet cars had alcohol based one for some reason at some point, which doesn't make sense). >>1614168>пyтин нeт!Пyтин пидop и нe мoжeт пepecтaть cocaть хyи.
>want to read up on differences between thermistors and thermocouples>go to first google result>wow ntcs are better in almost every way>notice the page is from a manufacturer that specializes in NTCsalmost got me
>>1614182tdk right?? haha
>>1614182NTCs are easier to use though. You can make thermostat with them with only two components.
>>1614151What about this fix??
>>1614248it would be better to just transmit the pulses digitally through the opto and filter on the output side
>>1614262but I need current though
>>1614033>how much did you want?>10ccs for $36fuck no
>>1614288pretty sure that's 10x10ccs for $36
>>1614295It's still pretty bad compared to rosin paste.
>>1614134If size is a concern, you should probably just order your own custom PCB.
>>1613987digispark my bro
Hey guys I want to make a shocker project, and I grabed a harbor freight electric fly swatter, I did some googling and came across a sparkfun blog that I believe uses the same schematics.>https://www.sparkfun.com/news/2094>pic relatedI am wanting to do similar project someone did, called shock potato, but make it smaller.I figured the components from electric fly swatter would be sufficient, but my question is, is it possible to give it some more umpf? I want to use a coin cell battery to power it, I don't know if thats possible, I mean yeah it can be powered by two D cell batteries, but I am sure other things are factored in. Maybe adding a capacitor, and then have the capacitor discharge when contact is made?
>>1614336I don't think I'd need a PCB for this where a simple protoboard would work. It's not much more than a 555 timer, a cap, and a resistor.
>>1614341People usually use a larger output capacitor to increase the punch of those things. Messing about with the passives on the primary side of the circuit might increase the frequency, which would usually increase the amount of magnetic flux being coupled.>>1614346If it runs off a battery I'd think twice about using a 555, their quiescent current is awful thanks to having 3 5kΩ resistors in series from Vcc to GND.
>>1614407>If it runs off a battery I'd think twice about using a 555, their quiescent current is awful thanks to having 3 5kΩ resistors in series from Vcc to GND.Planning to run on a microUSB or similar 5V from my PC.
>>1614341you can increase the umph by using a bigger storage capacitor, C1. you can technically use a coin cell to generate the charge but you'll probably have to make a custom circuit because those cells can't supply much peak current.
is there a preferred Arduino IDE for Linux besides the official one?
>>1614435In that case it's fine. Though I hope you have some of the 2-pin micro-USB sockets, as the 5-pin ones are a bugger to solder.
>>1614033>activatorsit says it only contains rosin and ethanol
>>1614033>MC34063I'm pretty sure buck boosters can't go rail to rail, if you feed 3V in can you get 3V out for example?but if it can take 3 - 5V in and shit out 3.3v out at all times that would be perfect
>>1614522A buck-boost converter can do the 3V-5V > 3.3V conversion. But personally I'd consider using a boost converter to 5.5V or more with a linear regulator to drop it to 3.3V for optimal ripple rejection, or a buck-boost converter to kick it up to 4V or so followed by a linear regulator if that would be more efficient.
>>1614555>boost converter to 5.5V or more with a linear regulatorinteresting solutionbut that requires two extra parts instead of just one and it would be wasting a lot of energy which kind of sucks with battery power (and i can't use more batteries in series to raise the voltage without the booster)
>>1614560If the ripple from a normal switching converter is fine then there's no reason to add an extra linear stage. But dropping 0.5V or so with a linear regulator wouldn't be too bad for your efficiency if you went for a buck-boost and some 3.3V LDO.
>>1614561i bought a roll of lf33 ldos which i'm going to use, the booster is about 85% efficient? i guess so with the ldo i am looking at about 20% energy waste? i guess that isn't too bad and it will save me from having to do extra fuckery like using opamps and mosftets to bypass or not bypass the regulator on the IC VIN depending on the battery charge state
>>1614563If you can buck-boost it to 3.8V, then the 0.5V drop will be a 13% loss in the LDO. But LDOs operating at such low voltage drops tend to have worse ripple rejection, so I'd mess about with an oscope until you can make a decision. Or just run your circuit off a buck-boost converter and see if it likes it. The 5.5V boost method would mean losing 40% of your power across the LDO, which wouldn't be very nice for something with a battery on it.Your LDO has a dropout of 0.45V at minimum, so you'll need to feed it at least 3.8V or so. But perhaps your circuit elements can run off lower voltages, like 2V. I know half my MCU ICs can run that low. If so, it would be a simple matter of using a buck converter or LDO to take it from 3-5V down to 2.5V or lower, assuming you can get such an LDO.
>>1614458Ugh no, if you are feeling hardcore you can just use the MCU without the arduino bootloader
>>1610590i'm a brainlet but can use a soldering iron, i have an old thinkpad and cant find oem or chink batteries anywhere so think i need to cell swap. I cant find any info on the batteries inside the oem battery. Would it be safe to swap these with 18650s?
>>1614611On this note, what software/IDEs do people here use to write code for AVRs? And then what hardware/dongle do you use to program them? The USBASP things I'm seeing on ali have 10 pins on them, which sounds a bit large but I guess it's meant to be flexible.
>>1614653They use 18650s but the Thinkpad batteries are glued shut and the cells inside are spot welded on tabs. It's almost impossible to replace the cells non-destructively.
>>1614662this is a very old thinkpad that pic i posted is the internals of the battery, I have no idea what type of cell those are and they have no writing on them
Question about microcontrollers, and LED drivers. A while back, I bought a kit that used a PIC16F1783 controller (preprogrammed) to drive an LED array. The kit suggests blue LEDs will work, but none of my blue/white LEDs are lighting. I tried lighting one on a breadboard, and it will not turn on until ~2.3V. When I measure the output on a scope though, the highest peak only goes up to 2.0V.Aren't LED drivers supposed to up the voltage to any arbitrary level, while keeping current at say 15mA? If so, why isn't my LED lighting? The accompanying resistor is only 100ohms, that should be more than doable for a 5v output. Would the programmer be setting some kind of internal limit? Or does the fact that it peaks at 2.0V imply the problem is elsewhere (say, at a red or green LED)? I can provide handdrawn schematics if needed.
>>1614665 Check your mcu power supply. Is should not dip bellow 3.3v when all leds are lit.
Anyone here know stuff about bootstrap gate driver???
This is lawnmower switch. What is that white shit for?
>>1614671Smooth as the day it was born. Although I just found a 5V rectangular spike at one of the negative data pins, lol.
>>1614696Total amateur here, but my guess would be a film decoupling capacitor to get rid of switch bounce
>>1614702Why would a lawnmower need debouncing? Three is no ic there
>>1613854Buck converter. Once the input drops below the threshold voltage, the duty cycle will sit at 100%.>>1614033A 3x063 isn't a great choice for a low-dropout buck converter. Using the internal transistors is going to add 2 diode drops. So you need an external switch; either that needs to be PNP/PMOS or you need a high-side driver.A dedicated buck converter IC (e.g. L5983) would be better, although you probably aren't going to find one in through-hole.
>>1614693that kind of motor will generate high-voltage sparks when you switch off. the white cap will eat some of that energy so the switch is less harmed and lives longer.
>>1614654Hit up www.microchip.com They bought out Atmel a while back and are slowly integrating the uC's into their development suite.The Atmel Studio 7 IDE is still avaliable, but MPLABX is now supporting some AVR's.Same goes with programming, old hardware can still work, but the newest generation of programmers/debuggers should include AVR functionality.
>>1614654I just use avr-gcc to build, avr-binutils to link etc., avrdude and USBasp to download into the chipthe 2x5-pin callout is an Atmel standard, there are adapters to a 2x3-pin callout as well>>1614665unfortunately, "driver" has come to mean both dc-dc converters and mere power switches>>1614729>A 3x063 isn't a great choicefixed kekyou are correct on all accounts. that said, that OP wasn't so concerned about performance as about low-end manufacturability
>>1614653Yes.But you better solder them fast, otherwise plastic rigie goes melty-melty, and battery goes shorty-shory without any protection.
>>1614662Acetone, or even better, gasoline on seams?
>>1614858yeah ive soldered them for stuff before, just not sure if the batteries will be okay to swap as i have know idea what voltage they are
>>1614867Those are probably Li-ion cells with same voltage range as modern 18650, so I think yes.Check label, divide voltage by number of cells in series, if you got 3.6-3.7V - you're safe.
>>1614869the batteries have no labels on which is why i asked kek, thankyou for the help guess ill jsut order some cells and try it out
wow this 10-pin standard is inefficient as fuck
>>1614914imagine that there's a ribbon cable with IDC connector plugged into it, and consider the layout of the signals on the wires. note especially that every signal line has a ground return (or two) as close as possible, for best signal integrity and improved emissions. it's been fairly commonly done with dual-row connectors since at least the 1970s e.g. floppy and hard disk interface cabling from the late 1970s
>>1614924yes but I'm not exactly uploading code at 500MB/sthey should just use coax like the cool guys
>>1614407>>1614436Thanks for the help, I took a look at the writing on the capacitor, and this is whats written on it.>224j f>400mpsa.2the gap between "224j" and "f" is intentional. IDK what the represents, but I added it just in case.So I did a google search on 224j capacitor, and it showed me similar looking capacitors on amazon, with higher volt rating, 640v for example. I did a full search on "224j 400mpsa" and didn't get much unless I switched it to "224j 400vpsa" I am guessing the 400 means 400 volts?Also what can I check or do, to see the max voltage the circuit can take without frying it?
>>1614962224 means 22 and 4 zeroes = 220,000pF = 220nF. The j and f are tolerance and maybe temperature ratings.400mpsa.2 probably refers to voltage. I'd throw in a 470nF or 1uF class-X capacitor as a replacement.
>>1614925son, that starts to matter at several MHz>>1614962>224J220nF capacitor, ±5%>400 voltsprobably, the 630V or 1000V would probably be better for replacement if you're going to up the value>MPSif it were "MKS" it would indicate a polystyrene dielectric
Ok, I'm faced with a few different oscilloscopes I could walk home with:>100MHz Hitachi VC-6545 Digital Storage Oscilloscope>100MHz Hitachi V-1565>50MHz Hitachi V-552Since the 6545 has "save", "hold", "storage", etc. not directly off the traces but with an ADC in there. I didn't think it would be an issue, and that it might be beneficial to be able to pause the trace, but someone more experienced than I stated that he'd rather have a more analog model since that would mean no quantisation error among other things.Does anyone here have an opinion on these early digital storage oscilloscopes compared to their forebears? I'm currently scouring their service manuals for anything akin to a block diagram that shows an ADC on it, but it's slow work.
>>1614976come on, now, a DSO is always better. some things just cannot be seen otherwise. the lack of smooth waveforms is a minor point by comparison. (find a yng boy and admire his smooth hairless curves instead.)
>>1615072Well both have CRT screens. I ended up getting the 6545/DSO one since after some testing I figured out the "real time" digital mode was something that could be toggled. It also has surprisingly good cursors and a frequency readout and what, so I think I made the right decision.
It is too messy for 3 Amps???The PCB size is 10mm*10mm
>>1615105Looks like some of those traces could be made shorter, like VS12. Also I might consider putting multiple vias to join those lower traces on VS34 instead of just one on each side. Also in general the clearance distances you've given aren't very consistent, especially VS34 with U3 and those red traces in the middle that are basically touching one another. I'd see about making your circuit a little more compact and more linear, since there's a big void in the middle and I bet a lot of parts could be positioned somewhere more efficient. Like R4, make it point in the same direction as R5 to shorten that backside trace going to U3. In fact I'd start placing components all over again, since it doesn't look like enough effort went into choosing where they go in the first place. But I'm no expert.I also find your adherence to 90% THT parts with only 5 SMT parts unusual.
>>1615105to carry 3A at a 5°C temperature rise on 1oz copper, you need a 2.1mm track width, minimum, which will drop 70mV per 100mm lengthas long as you dont have excessive inductive or capacitive feedback that matters for your circuit (not really feeling a full design review rn), and your traces are separated widely enough (see IPC-2221 or a derivative for spacing guidelines by voltage) it will probably work, but extra layout effort would be well repaid
>>1615109imo SMT elcaps are more pain than they're worth for hand assembly
>>1615113Yes but why THTs for all the ICs and most of the other passives? Why use any SMTs at all at that point?
>>1614741But it's an ac motor, wouldn't that cap just cause a short?
>>1615116Capacitors have a finite impedance to AC, the actual current drawn won't be too high at all. Perhaps on the order of a dozen mA. And in normal operation this impedance will actually cancel with the AC motor's impedance and cause the whole thing to draw slightly less current.When the switch suddenly breaks the circuit, you'd usually have a freewheel diode to stop the inductive kickback from arcing through your switch in a DC motor. Look up how this works if you're unfamiliar. The same applies to an AC motor, but they'd have to use two HV zener diodes in antiseries to get the same effect since the voltage goes 170V above and below the neutral line in normal operation. This circuit would result in a significant power being dissipated in the diodes themselves since they'd have a >180V voltage drop across them, where a single diode in a DC motor circuit would only have 0.7V or so across it, the rest being across the motor windings' resistance. So instead we use a capacitor, which absorbs the energy stored in the windings and rotor, and bounces it back again in the other direction (and again and again), without dissipating much energy as heat at all. Ideally the motor windings will have much higher resistance than the capacitor, which can usually be assumed to have an ESR significantly below 1Ω, resulting in the vast majority of the power being dissipated in the motor windings, which is fine because of how large they are and how much room to radiate and convect away heat they have.This capacitor would also work on a DC motor, but the driving circuitry for a DC motor would likely not be hardened against negative voltages, and the capacitor would result in a much more negative voltage (some significant fraction of the main driving voltage) than the diode (-0.7V or so).
>>1615114that may be a question of what that anon bought off alibay and has in stock. for me it usually is>>1615116capacitive reactance decreases with increasing frequency and increasing capacitance: Xc = 1/(2*pi*f*C)the reactance of a 1µF cap at 60Hz is ~2700 ohms. reactance at 60kHz is 2.7 ohms. mains frequency currents would pass poorly through the cap, but sharper spikes (harmonics reaching into the tens or hundreds of kHz) would pass very well through the cap
>>1615120>what that anon bought off alibaySo he's either in the awkward transition stage between THT and SMT, or he found some parts are only available (at a reasonable price) in SMT? Well I guess bought some SMT SA602s for the latter reason, but since fab houses usually want you to order like 20 copies of your board I'd think you'd be buying parts specifically for the board anyhow.Also I just noticed there's not much in the way of bypass caps near his ICs.
>>1614729>Buck converter. Once the input drops below the threshold voltage, the duty cycle will sit at 100%.Do all bucks work like that? that if you supply less than required minimum voltage they will become "shorts"?
>>1615122it's been my experience that the chink proto houses are fine with 5-orders. they probably make 10 and toss the other 5>specificallysome, perhaps. but if you've got fifty of "everything" somewhat organized in bags in boxes behind you, for repair and for new construction, the only things you'd really need to order are unusual ICs and maybe some 1% resistors>>1615130no. some observe a maximum duty cycle or minimum off-time
>>1615113if you don't mind the base getting a little melty they're fine with paste + hot air gun or just iron on each side.
>>1615133>no. some observe a maximum duty cycle or minimum off-timeisn't that the same thing? maximum duty cycle would be just on all the time and minimum off time means also on all the time
>>1615130He means some have a maximum duty cycle less than 100% and/or a minimum above 0%.Simple hysteretic buck converters will naturally do 100% duty cycle if they can't achieve the threshold output voltage. The L5983 mentioned specifically states "Low dropout operation: 100% duty cycle". The 3x063 can't do 100%, and isn't particularly good for buck converters anyhow.A buck converter has the switch on the high side, so to obtain saturation you need either a PNP/PMOS switch or a drive voltage a few volts above the input voltage. For the latter option it's common to use a voltage doubler driven from the switched output voltage, but that won't work if the converter is running at 100% duty cycle.
>>1615149sorta. not all converters are PWM machines. some use pulse-frequency modulation at low loads, PFM at all loads, or a hysteretic switching scheme. therefore it doesn't make as much sense to characterize PFM or hysteretic switching relative to a cycle that isn't part of the calculation
>>1615216no. some converters have a max duty cycle of 90-95% in order that the output switch is never continuously on. particularly for boost converters, that would be catastrophic. similarly, converters in PFM mode vary the on- or off-time to regulate the output, while holding constant the other time
>drilling my first holes in aluminium enclosure for guitar pedal>drill fucks off on me when drilling pilot hole despite center punching it>hole is several millimeters offFUCKGuess drill presses aren't a meme.Maybe I should get a new drill bit first though.On the other hand, I'm amazed how well a $2 chinesium step drill bit cuts through it like butter.
>>1615437Fuck drilling aluminum, especially the thin bullshit. I've raged so many times doing the same thing
>>1615383I mean yes>>1615437that is correct. ditto deburring tools, but mind your hands when using them
let's say I have 4 oscillators running off of a 40106how would I mix the 4 signals together without exploding somethingsend them all to a common rail with diodes on each output?
>>1615463feel free to use the op amp of your choice
>>1610590Noob here trying to build an AND gate.Resistors are all 10k apart from LED one which is 250ohm.It works, but when the right button is pressed by itself 0.2mA and 1.7v gets passed through, dimly lighting the LED.How do I stop this?
>>1615500The preferred language of electronics is the circuit diagram.
>>1615500Probably some leakage current consider this >>1615519
>>1615519>>1615522Works perfectly, thanks anons, I can see how this avoids the problem because the leakage current now just leaks to ground instead of through the LED.I'm still a bit confused on how I would make use of the output in this "component before the transistors" configuration though. Obviously it works with an LED because the transistors connect it to ground, but how would it work for an IC? If I wanted to pull an IC pin high with this AND gate, where would I place it in this circuit while still avoiding leakage current?
>shitty tegaki drawingi'm pretty familiar with the op amp regulator topology, but i don't know anything about representing it mathematically. i want to be able to work out the transfer function for this system and write out the bode plot by hand, so i can understand how to optimize it. are there any good short form web sources on how to do that? i took differential equations in college but i don't remember a single thing from it.
>>1615552also if this is something i can't really learn without having to open a textbook then that would also be helpful to know so i don't waste my time.
>>1615552Just spice it? You could give the calculations a shot, but it wouldn't be terribly nice looking. I'd start with the simplest version of that regulator (i.e. without superfluous capacitors and such) first.
>>1615542it's not actually leakage current. it's base current. it's supposed to flow and is essential to transistor action. if you were using n-channel MOSFETs instead of BJTs (which are voltage-mode), you would not be seeing that effect. you'd be seeing a slightly different one where the source voltage is some volt or two above the gate. that's why logic implementations tend to prefer placing the anyway, as regards voltage levels, what you have now is an open-collector NAND gate. add a pull-up, then negate the negation with an inverter stage with its own pull-up>>1615552also interested in network analysis and would like to know this
is there a book on practical circuit design and practical circuit knowledge?The Art of Electronics is good and all, but I want to learn shit like how to design a portable charger from 18650s, how to design an audio amplifier, what makes one implementation of a circuit better than another, etc
>>1615671as long as a circuit meets specs, some figures of merit include area, cost, size, insensitivity to manuacturing variations, operating margin, tolerance to abuse (e.g. ESD), etc. the importance of each of those figures of merit varies by application and industryconsider just looking at existing circuits or ICs that do those things, especially those that include detailed documentation of what's happening when and why. you will gain some understanding of the parameters that are important to your design and be able to select parts for your design. much of the design process is just taking standard topologies, selecting components for them, and integrating them into a finished whole
Ooh, looking inside my new/old function generator it's got some CDIPs in it. Namely: MC1445 amplifier and 10116 line receiver(probably being used as a comparator). There's also a large PDIP ICM7216 that's a dedicated frequency counter and 7-seg display driver, and the entire board is covered in aesthetic curly traces. Also some of those pots are really cantilevered. And the central potentiometer has a gearbox in it because the knob can be rotated multiple times before the pot inside hits the end of its range. On closer inspection, the gearbox has to be inside the knob itself, as there's no room elsewhere.The model is a Newtronics 200MS.I'll get around to posting the internals of my scope later.
if transistor amplifies the base current, what happens if you say supply 10ma on the base which results in 10A through the transistor, but the connected load only needs 500ma? will the transistor force 10a through the load?
>>1615732If your mains socket can supply 10A but your 100W light bulb only needs 1A, will the socket force 10A through the bulb?
>>1615732>will the transistor force 10a through the load?the transistor would be creating energy in that case and fossil fuel companies would be on suicide watchwhen the base current * beta > collector current as externally limited, the transistor is operating in the saturation region. there, Vce has a sublinear dependency on collector current, often specified in the datasheet. a BJT takes quite a bit of time to desaturate and reenter the active region (which may matter to you if microseconds matter to you)
KiCAD v6 roadmap:>- Study ergonomics of various commercial/proprietary PCB applications (when in doubt about any particular UI solution, check how it has been done in a certain proprietary app that is very popular among OSHW folks and do exactly opposite).kek
>>1615748Step 1: Steal from competitionevery roadmap ever
>>1615748>proprietary app that is very popular among OSHW folksWhat are they referring to? EasyEDA or something?
>>1615751I figured EAGLE
>>1615753eagle is a joke nowadays
>>1615714Here's the scope in analog mode:
>>1615772And here's it in digital mode:Pretty nifty if you ask me.
uh oh.. i just accidentally took a sip from a water glass on my table and then realized it is the same glass i used to wash my etched pcb in, to clean it from fecl3 am i in some legit danger? nothing seems to hurt and it was just a small sip, but i did swallow unfortunately
>>1615773And this scope has an RS232 port on the back of it, which is where I assume you can extract the stored data. Trying to interface with it with custom hardware might be fun. If anyone here has experience with this I'd love to hear from you.Haven't figured out a few of the features though, namely what exactly the horizontal mode switches (A, Alt, B, where Alt + B = X/Y) do, and what the Mode switch does (Auto, Norm, TV-V, TV-H). Perhaps the TV modes are used for troubleshooting a TV's vertical and horizontal scanning, so you'd be able to look at the sawtooth waves and see what's what.I also saw a neat video on hackaday where someone used the VGA port on a computer as a DAC (combined with 3 resistors on a tiny PCB) to feed an oscilloscope's X and Y channels with data to display vector images, animations, and even live games. Turning this oscilloscope into a vector screen for my raspberry pi could be interesting, if I could actually pull it off.>>1615798Got any boric acid to wash it down with?
>>1615798There's already ferric chloride in your tap water.If it's watered down it's not dangerous.
>>1615798>i just swallowed heavy metals, how many new livers do i need?
>>1615802>There's already ferric chloride in your tap water>your>implyignI bet it's used in less than 10% of places with treated water.
>>1615804It's a pretty common flocking agent, it's not some leaded American tap water third world thing.Have you checked your local sewage treatment report?
>>1615806>Have you checked your local sewage treatment report?all lies. do you really think the gov admits they are putting stuff into water to turn the populace more obedient?the only report you can trust is the one where you perform the tests yourself
>>1615604Thanks very much, your diagram makes sense, I'll try it out when I get home from work.You missed off the end of this sentence here though, can you clarify what you meant to say?>that's why logic implementations tend to prefer placing the
>>1615833Ever heard of diode logic? For cases where you aren't having more than 1 or 2 gates cascaded it might be the better method, at least as far as ANDs and ORs go. Something about putting two NPNs in series like that doesn't sit right with me.
I noticed that industrial ICs which are supposed to run for years on battery use all some sort of purple batteries. What sort of magic is that? Are they different from regular lions?
>>1615849Long life lithium primary cells (not rechargeable), many colors, incl. purple.>What sort of magic is that?Selective perception; "all", see?
>>1615552For most purposes, the transistor in that circuit can be modelled with just Ve=Vb-Vbe, with Vbe constant. If that isn't enough, there's the Ebers-Moll BJT model, but if you use that you won't be able to solve the system analytically.An ideal op-amp is modelled as V+=V-, and the rest of it is network analysis (which gives you a system of linear ODEs).
>>1615835Hmm, ok. I've heard of diode logic but I don't know anything about it, I'll do some research later.Do you know of any good online resources that walk you through creating different types of logic gates, or are books the best place to learn about this stuff?I know none of this is practical in modern circuits because ICs exist, but I find it very interesting.
If I have a 12V linear regulator that can take say 15-32V input and I just rectified say 20VAC.Would the regulator have any issues if I didn't do any smoothing after rectification?
>>1615891Yes. Rectified AC will be zero near the zero crossing, and a linear regulator can only reduce the output voltage below the input, it can't increase it. So you'll get (roughly) a rectified sine wave with the peaks chopped off. The filter capacitor needs to hold enough charge that the voltage never drops below the regulator's minimum voltage even when the rectifier output is below that level.
Is this just a simple inductor or there is something more??
>>1615833...input transistors' emitters/sources against a fairly solid voltage (with the notable exception of TTL which uses a common base arrangement for its inputs): so input levels aren't state-dependent>>1615877if you understand the components, you can walk yourself through it. just look at a particular logic family and trace currents/voltages through each possible set of inputs x state of the circuityou might try a university text. I learned a few things from Roth's "Fundamentals of Logic Design"
Here I have a lipo battery voltage indicator with a comparator that has hysteresisbecause of that the base current is at like 10uA according to falstadnow I never manage to saturate my transistor and because of that the voltage at the emitter never reaches 5V but 3.7V according to my measurements on my irl test circuitwhat can be done here?
>>1615940Btw the transistor in my test circuit is a bc547. I'm okay with 3.7V but I'm afraid that the smd transistor in my schematic will not be able to supply that voltage. I don't really understand its datasheet
>>1615940What do you expect the circuit to do?
>>1615943You can treat the two transistors as almost identical.
NEW BREAD :DD>>1615963>>1615963>>1615963NEW BREAD XDD