/diy/ - Do It Yourself

>>1981448
wat do.

>>1981505
Put it in a metal tin and bury it

>>1981505
>wat do
Disassemble, puncture, crush, heat, and burn

>>1981507
all jokes aside, what do normal people do when they encounter something like this? I take old cells to a shop in my area that handles them. I know people that have old phones/electronics in shoeboxes from moving with batteries in them. Will we start seeing housefires from ~2010 electronics?
This came out of an Iphone 3 I've had since new. It's my alarm clock on a bose dock.

>>1981505
throw in bucket of salt water to safely discharge, then legit just stab it with a long stick to release pressure, toss in trash

>>1981505
eat it

>>1981505
puffy

fug this is gonna take it outta me

>>1980970
>>1981560
Here's the first board, ready for etching. I've always wanted to do curly traces like this.

>>1981594
Looks like art to me.

>>1981594
machinist lurking this thread out of curiosity, is drilling accurate holes really an issue for the home electronics guy? im aware of how gummy copper is, but if you can flood the piss out of ur tool with some kind of lubricant, its a breeze

>>1981594
Are you etching the board or what? I've been looking for a way to etch brass but it seems kind of complicated. I really want to use a laser and I am getting mixed results. Some say as laser won't work to etch brass. Others say it can only "mark" the brass. Some say you have to use a special chemical applied to the brass to etch it, but it really just marks the brass with the chemical from the laser. Another option would be some sort of CNC machine. That would be true etching as the material would be removed, but I don't know where to start with that or even with the laser idea.

>>1981647
Thanks!

>>1981688
It's fine if you have a drill press and some good way of holding the 0.5-1mm drill bits. A hand drill or pin vice will work fine too. I've just decided not to do so for this, because I've always wanted to.

>>1981696
Yep, etching, with ammonium persulfate. Though I think there's some very thin smears of solder mask in some places that will prevent etching, so more scratchy scratchy it is.

Depending on whether the laser is a diode laser or CO2 laser, and what power it's got, will make a difference to what you can do with it. Unless you've got an industrial-strength laser I doubt you'll be able to cut more than 0.5mm or so of any metal. Lasers cut by heating things up until they evaporate or burn away, and most metals conduct heat too fast for that unless they're really thin. Not to mention brass's nasty fumes.
I've seen laser anons cover their PCB with spray-paint and laser off what they want to get rid of, and etch that in normal etchant. This is an easy and fast way to make an accurate etching mask without needing to do inkjet or laser printer stuff. I imagine this will work fine for brass too, but the depth you want to etch will need to be insignificant compared to the width of features.

Chemical-wise, the zinc in brass may well passivate it against further attack, so you'll need to look into what can dissolve brass. I wager that an oxidant like H2O2, persulfate, or Fe3+ should work just fine so long as the solution is acidic enough, for which common citric or hydrochloric or whatever acids should suffice.

>>1981448
Anyone got any recommendations for cameras >640p and potentially >30fps that I can interface with an FPGA? So far I have developed a verilog interface for the OV7670 and am looking for something with higher resolution to do some rudimentary visual tracking.

>>1981813
Raspnerry pi cameras are digital and meant to be interfaced with directly via the MIPI standard. They're also dirt cheap.
https://hackaday.com/2020/03/11/getting-1000-fps-out-of-the-raspberry-pi-camera/

so i was trying to replace my kitchen halogen bulbs with led's but it won't work unless i keep at least one halogen bulb plugged in, the moment i make all bulbs led it stops working, wat do?

>>1981843
pic rel

>>1981843
>>1981844
Are those mains voltage bulbs?

>>1981594

there's a good chance your dirty fingerprints all over that poor PCB will act as etch resistant, just like the red stuff.

>>1981843
>keep at least one halogen bulb plugged in

you probably have a dimmer, or a timer switch, and it needs a minimum load to operate.

>tfw soldering too close to the plastic case and now the case is fucked because of some melting part

fml

>>1981865

best way to avoid future mistakes, son, is to not do anything ever again.

>>1981858
>there's a good chance your dirty fingerprints all over that poor PCB will act as etch resistant
That was just dark copper oxide. Looked worse in the photo. Witness me.

>>1981868
Chipping off the solder mask was actually kinda fun. But the thicker it was, the more likely it was to take neighbouring pieces with it, as you should be able to see in some places. But considering this was like a 2-day 3-step prototyping method that gave me a PCB with solder mask on it, I'm pretty damn happy. Well, I'm more happy about not having to use any jumpers on a single-sided board than anything else.

Is it possible to buy a "beginner compotent kit" from jaycar with all the necessary resistors, capacitors, etc, that I'll need to go through a beginner hobbiest book.

I don't like leaving the house often, so if I could get all the necessary components in one go that'd be perfect.

>>1981966
you should be able to check the grab bag of parts for a list of components online.

they probably dont have any potentiometers in the kit so you may have to use resistors in parallel to reduce resistance and in series to add resistance. two 10k resistors in parallel make a 5k by opening up more room for current and resistor wire or metal oxide film or carbon film has set resistances because of length the electricity travels and volume of material it can cross (how narrow the path is). so you can augment fixed resistor values by pairing them up in parallel and series

>>1981966
Google standard resistor values, standard capacitor values, and standard inductor values. Then list them all and order them >10 each, just to be safe, buy 1W resistors only, don't go any lower. Also just to be safe choose 1A or more inductors.

Realistically would you guys put any of your DIY projects on your resume?

I'm an electrical engineer struggling to find a job right now with no experience, IDK if the shitty little circuits I put on my portfolio are worth anything or if I'm just making a fool out of myself.

>>1981979
really it's better than nothing
brd or pcbjob files of little break out boards are helpful for an employer assess how organized you work

>>1981979
>IDK if the shitty little circuits I put on my portfolio are worth anything or if I'm just making a fool out of myself.

Simple test: would you show it to someone with your exact same experience and expect them to say "wow, how did you do that", or would they say "yeah, I saw that on adafruit too".

>>1981979
>Realistically would you guys put any of your DIY projects on your resume?

yes, but just a select few that's the combination of 2 or more tutorials, at least it shows that you are a do-er and has proper problem solving skill.

>>1981979
It shows you at least have an interest in the discipline, which is a plus IMO

found a ups transformer that has wires not made of copper
it's a silver metal, nonmagnetic, cant be soldered to easily, doesnt melt at soldering temperature
what is it?

>>1981990
you're not supposed to impress anyone with your hobby projects
it lets employers gain an insight on how professional your documentations are

nevermind its so light it must be aluminum

>>1982001
it's alumunium

>>1981979
Depends on what it is.
Does it have anything to do with an arduino? No.
Does it have input, processing, and output? Yes.
Right out of college I put together a small binder with all the data in it from my final in college - I built an X-Y plotter from scratch. All my code, CAD files, everything to include revisions from start to finish.
The company that picked me up had a few people in the interview and they loved it. They said it really set me apart because it showed my progress and ability to design something from scratch and not using existing code/schematics from other people.

>>1982002
>you're not supposed to impress anyone with your hobby projects

This just might be the stupidest sentence ever posted to this general.

>>1982012
feel free to impress people

>>1981979
EE student here looking for a internship. I put it at the end like
>experimenting with hobby electronics doing pedals, small converters,sensors etc
Just to let people know that I know the basics because I have a lot of classmates who do not.

>>1982026
experimenting with hobby electronics since 20xx*

>Mims III, Getting Started in Electronics

am I the only one who is really struggling to read this?

>>1982076

Mims is for noobs. if you cant even handle that, then you need to go away, back to Legos.

>>1982076
It's Dr. Seuss for electronics.

>>1982076
The "Written on lined paper" angle of the pdf version in the OP is a bit annoying but the actual content isn't particularly complicated. Anything in particular you don't understand?

I recently salvaged a power supply from a disfunctioning printer and it can deliver either 8.5 V or 24 V. It made me curious about what kind of system works with 8.5 V, it seems unusual. Does anyone know what system needs 8.5 V?

>>1982097
>>1982104
>>1982118
im not struggling with anything related to the content i meant just its entire lay out is really hard to read. idk

>>1982127
brushed DC motors in the printer

>>1982130
Mims is really bad. Just get another book or start a project and ask what to do here

>>1982132
I don't think so as there was only DC motor in the printer. But thank you for the guess.

>>1982138
What kind of printer?

>>1981979
i link my sarcastic electronics blog with like 2 projects and a bunch of rants, am i doing it right?

>>1982127
8.5V might just be there for a linreg to step down to logic level, with the 24V being for the motors
that or the 8.5V is for the motors and the 24V is a low current rail for the inkjet piezos
or some combination

>>1982130
Try switching to "make: electronics" (C.Platt) and see if that works.

>>1982141
A HP inkjet one of my memory serves me correctly.

>>1982206
>>1982206
so it def has more than 1 motor. At least one for the carriage and another for the paper rollers.

>>1981511
>what do normal people do when they encounter something like this?
Ignore it until it stops working, then throw it in the garbage can. Unless the failure results in a fire, then they call the fire dept. While they are waiting for the fire dept, they take really deep breaths. Normies have double digit IQs now that diversity is our strength.

This might be a stretch for the electronics general but it's worth a shot: I have a 3/4 HP, 2 speed induction motor (for an evaporative cooler) that will only start on high speed. Once it's started I can switch it back to low speed no problem and it runs just fine, but it won't start on low.

Any ideas what would cause only one of the speeds to start, or how to fix it?

>>1982278
Capacitor is probably fucked. Being able to switch speeds down means it's not likely it's the control circuitry. Check with voltmeter to see if proper voltages are getting through when it won't start just to be sure. Get new cap if voltages check out.

>>1982278
Just guessing, but change the start/run capacitor.

>>1982284
>>1982286
Dang, I just replaced the cap with a new one from Temco but still won't start on low. I've never had any issues with low voltage or bad wiring here but I'll check the voltage.

Is it a bad idea to run these motors with no load? I'd like to try taking off the belt and checking if the motor will start just by itself. The bearings on the motor and the blower seem fine, they both rotate freely and I've kept them lubricated, but I just want to be certain it's not too high of friction in the bearings that's preventing it from starting.

>>1982290
Are there 3 terminals on the cap? Maybe you switched two of them around.

>>1982295
Nope, only two. As far as I know start caps like this are non-polarized, and on the ones I have (both the old cap and the new) there are no markings, plus both leads from the motor to the cap are black, but I can try switching them to see if it makes a difference.

>>1982278
Time to move up to a drive, start caps are so last century.

>>1982284
>>1982290
Just checked the voltage, it's 122.

Tested something else because the motor occasionally does start on low. I rotated the blower fan (and with it, the motor) a little, maybe a quarter turn, and when I plugged it in again it started. So it will start at certain angles. That leads me to think something is wrong with the windings but... what? I'd think that an issue with the windings would either burn something, flip the breaker, or cause it to not spin at all.

>>1982313
Move up to a what now?

>>1982314
one of them freak drives, makes motors move using some solid state tomfoolery

>>1982314
How old is the motor? Has it been used heavily?

>>1982327
It's about 15-20 years old. The house has been vacant much of that time and also has an air conditioner, so this cooler's only been in use 6 or 8 summers total.

If it's an issue with the windings I figure I'll have to get a new motor anyway, but I'd really like to know *why* exactly it failed. Like why does specifically only "starting on low" not work while everything other running condition works perfectly.

Any way to reasonably check/fix windings on motors like this or is it not worth the effort instead of just buying a replacement?

>>1982334
>everything other running condition
every* other running condition

>>1982334
motor tester, megger, you could see if your local motor rebuild shop would test it but most of those little motors are pretty cheap so it's not really worth it.

>>1982314
>That leads me to think something is wrong with the windings but... what?
Opens and high resistances don't pop breakers. Any short in series with the capacitor will be protected by the reactance of the cap. You can check the current. You might get lucky and spot something obvious and fixable when you open it. I'd get a new one instead of bothering rewinding. Unless you want to rewind it as a personal project, it's not worth it.

>>1982338
>>1982342
>Opens and high resistances don't pop breakers.
Yeah, just watched a few videos on single phase induction motor winding/testing. Makes sense that nothing obvious would happen if the circuit is just open.

That must mean there are two start windings, one for low and one for high, and the low is open... or there's only one start winding and it's being shorted with the low speed winding. I'm curious so I'll take it apart and see.

Anyway, looks like it's replacement time. Much appreciated, anons.

>>1981448
why is the internet so dumb sometimes? people talking about charging a cap to a set voltage. like it climbs to that voltage. so instead of charging a 400v 100 uf cap at 400 volts they charge it at 30 volts until its full. its like none of them thought to test a cap from a disposable camera or polaroid with a 9 volt. it doesnt do shit . barley cuts on a led durring charge and discharging. do it with the transformer and circuit in it and you get sparks the second its shorted to any circuit if you have to make the connection manually

as a result im left wondering if the average person just parrots what they hear and doesnt understand Q and E . a 400 volt cap can be charged from the beginning to the end at 400 volts . it ends up with greater Q as a result. more stacks of 400 volts. charging it with less and measuring it with a volt meter gives you a car audio like effect where the cap is more like a short lived battery. the volt meter thinks its has a set voltage that declines at a slower rate

one day after covid kills off tons of people by turning into aids and suicides and civil unrest from economic decline i shall take over a building and organize truth in volumes written in blood on the walls. i will give it a clear coat to immortalize it in the ruins of cvilization

future generations wont be able to read it but they will make up stories of the elder gods who made the monuments

I would like to use one of those super capacitors as a 5v battery that lasts around 1 minute.
How safe are those things? Will I loose an eye if it pops on my face?

>>1982396
Why don't you just use a battery? Supercapacitors can decapitate you if you're not careful.

>>1982399
The capacitor would be faster to recharge.
The form factor should be small. I was thinking of one of those coin batteries, but I'm not sure if it will be able to provide enough current

>>1981966
Jaycar value per money is pretty shit. If you don’t mind waiting for shipping, get a kit from Ali or eBay or Amazon or wherever instead. Or look for a less corporate local one, like Surplustronics here in Auckland. Though it’s possible that you’ll be below the minimum free shipping threshold for them.

As for components, you’ll want a bag of assorted resistors, a bag of assorted ceramic capacitors (jaycar’s ceramic bag is reasonably cheap), a bag of assorted electrolytic capacitors, a breadboard or three, some LEDs, and breadboard jumpers. I’d also recommend getting some 555s, op-amps, comparators, buttons, and maybe some interesting stuff like LDRs and inductors and Hall effect sensors. Unless they’re in a bag together, buying those parts from jc will be rather expensive. This coming from the guy who apparently spent like 45 kiwi dollars on three OPA2134 op-amps. Go for cheapies like LM324s or LM358s unless you need otherwise. The jaycar bag of assorted transistors was passably cheap if I recall, though BC456, 457, and 458 (plus complementaries) isn’t as much variety as you might want. Definitely get some BJTs like that, some diodes (1N4007s and 1N4148s probably), and maybe some MOSFETs of some sort.

An arduino is a good idea if you’re into that, but please don’t pay $50 for one from jaycar.

I really don't understand stuff like this, but I thought I could get started but I'm even more lost

I bought these:
https://www.adafruit.com/product/3910
https://www.microcenter.com/product/456315/adafruit-industries-2x2032-coin-cell-battery-holder---6v-output-with-on-off-switch
And I wired them together and wrapped the exposed stuff with a bit of electrical tape

What am I missing to make a simple motor run?

>>1982442
It's a brushed DC motor. Dead simple to power, it should work.

>>1982466
that's what I thought, but nothings happening
is there any troubleshooting I can do?

>>1982472
measure voltage out of battery pack
measure resistance through motor pins
measure current when together

>>1982442

the motor needs 500mA, and you're using batteries that can deliver, at most, 20mA.

And it's done!
Except for the part where solder flowed inside the TRRS output socket preventing me from inserting my headphones. Gonna have to replace that and be more careful when soldering the new one, but I've got a bag full of them so I'm not worried.
I might try desoldering it by reflowing each pad and sliding a stainless steel spudger underneath them, the low thermal conductivity of stainless should work to my advantage.

>>1982557
>reflowing each pad

break the jack into bits using side cutters, then desolder the pads one by one.

you should drill holes to provide strain relief on the batt wires.

>>1982530
I'm not sure I understand this concept, can you let me know where I can read more?
I thought that batteries weren't limited by a specific current output

>>1982582
all batteries have internal resistance.

>>1982574
The spudger couldn't get underneath them. It was just for testing anyhow, I got it off my reflowing the single joint on one side, bending the whole thing up away from it, and steadily desoldering the last three, which worked fine.
Turns out the jack wasn't full of solder, rather just way too tight for my jack to fit in. After working another jack in and out it seems to fit, barely.

And I've got superglue on the battery cable for strain relief, because holes are for losers. Neat trick though.

>>1982582
Common AA batteries can have maximum output currents anywhere from ~30mA to ~1A, depending on their chemistry and structure. Go for high-end alkaline or lithium primary cells to ensure that your motor gets the current it needs, cheap cells give shit results. Lithium ion polymer cells can output over 100A due to their unique structure and chemistry.
See the datasheet of your particular cell for more info.

>>1982557
>plug it in
>power it on
>it doesn't work
>scope it
>the ancient 2nd hand potentiometer is fucked
really shoulda tested that first ay

>>1982601
>every single potentiometer in that bag had the front gang broken
what the shit
>replace pot
>works, but output making funny noises
>check scope
>whatever it is, it's too high a frequency to be seen at 50ns/div
>add cap from output to ground
>hold in particular way
>can hear the Mutton Birds' "Dominion Road" being played
what the fuck i made a radio

>>1982607
Yeah pretty sure the op-amp was oscillating, doing so at 250-450kHz with that cap, and 4-3MHz (and no radio) without it. That would explain the radio reception, though AM only goes down to like 550kHz.

Anyhow, added a cap from the output to the inverting input, which I think has solved it. It's still picking up a little noise from the outside, but that's just my soldering station's noisy SMPS. So it's working fine now, I think.

i got interested, so i'm heading twords build a computer. were at programming chips.

>>1982615
now you know why audioshit is usually inside a metal bawks

Yo guys. I need some help here! I'm at university and I happend to study subject called Integrating Art Music and Drama into the Curriculum. It's one of those optional classes u take just to have enough credits. I decided to finish this class by making something that can let you study and make sounds.
Well I tought about some analog circuitry which let u understand basics behind sound making and music making in general. Somethink u can hook on osciloscope easily.
Anyway first thing that come across my mind was simple 555 piano I build long long time ago. But I feel like that it's too simple.

I do have some knowledge about digital electronics. Microprocesors n shit. But analog electronics is still kinda mystery to me.

Can anybody experienced with this topic show me the way I should go with this?
Any inspiration would be good.

>>1982653
John withney made some cool shit
https://www.youtube.com/watch?v=HnlQa74H7is

>>1982657
>John withney
Thank you!

Looks familiar

https://www.youtube.com/user/jerobeamfenderson1

Is Quadrature encoding a design used by rotary encoders or are all rotary encoders quadrature encoders? I'm a bit stuck on the terminology.

>>1982607
touch pins 1 and 8 on an lm386 and you'll pick up a mix of chinese and religious radio

>>1982667
Quadrature encoding is used by incremental encoders

what's an easy setup to measure a small, low Q, 1-10pF capacitance?
>chinkmeter doesn't go below 20pF
>DMM doesn't either
>only pF test rig I have is a resonant tank, and this cap may be low Q
Some sort of square wave -> low pass filter?

>>1982693
oscilator

>>1982741
and if you have of the same you can always put them in parallel until your meter can measure it

>>1982693
resonant tank, with a strong square impulse, should be sufficient so long as your scope has single capture capability

>>1982741
what kind? I'm trying to find C_cb of a bjt fwiw, so idk how well it'd oscillate

>>1981448
project roll

>>1982795
Make a tank with an inductor of known value and a resistor of known value. Keep leads short and do not use a protoboard. Give it a step response or feed it a low frequency square wave. Measure the frequency of the ring.

>>1982795
Make a tank with an inductor of known value and a resistor of known value. Keep leads short and do not use a protoboard. Give it a step response or feed it a low frequency square wave. Measure the frequency of the ring.
>bjt
lmao, that is harder. I think they use capacitance bridges to measure it.

>>1982808
I used an RC LPF and got a reasonable value
1khz square through a 10Mohm resistor. Measured it with no caps (3.2 div tau) to get the output capacitance, a known 51p cap (6.8 div tau), and the unknown cap (3.8 div tau)
(3.8-3.2) * (51p / (6.8-3.2)) = 6.1pF

seems reasonable. I'd prefer a 10kHz or 100kHz square though

>>1982615
Ok, now that the preamp is done, I’ll see if I can make the distortion effect. Before driving down to the folks on Christmas Eve. While working each day.
The PCB layout is done (got it down to 5 jumpers with the same technique), and I painted a DIIC14 footprint and that of an audio socket this morning, and will have to have finished that by today to etch it overnight (or over dinner if I increase the concentration). Then I’ll solder and debug it tomorrow.

I’m doing more work over this week than I’ve done for 6 months. Hope the bastard likes his gift.

>>1982981
Actually I think it would be really cool to have a 24 hour circuit making project, where a bunch of teams are given a randomly selected project to make, and they’re to design, build, and debug it within 24 hours. Points would be issued on aesthetics, functionality, improvisation/creativity/uniqueness, and not having used a microcontroller for everything.

Maybe there could be some further goal, like design your own hardware to communicate with a particular satellite or something.

>>1981448
thermal fuse transformer guy from last thread.
could find any of the radial box shaped fuses so I have this one. any suggestions on how to get it to attach to the two ends on the transformer? soldering will burn the fuse so its tricky

>>1983092

just do it quick, and it'll work fine coz heat is slow-moving. tin 4 points, then 2 quick touches and you're golden.

How do I practice soldering to small contacts?
Pic related

>>1983110

if you use a 5x loupe, then you can solder stuff 5x smaller than using just your gay eyes.

>>1983103
do i need to wrap the fuse? can i leave the old leads attached? is there an ideal position to put the fuse in?

>>1983118
>do i need to wrap the fuse?

no, but you can hold it between 2 fingers to check it's not getting hot while soldering.

> can i leave the old leads attached?

yeah, you risk breaking something if you remove 'em

>is there an ideal position to put the fuse in?

right against the coil. ideally you'd use some heat-transmitting goo, but of course you dont have any.

>>1983110
>>1983115

in case you're not familiar with approved loupe technique.

>>1983123
>hold it between 2 fingers to check it's not getting hot while soldering
Chad move.

I’d also add that, after tinning the 4 contact points, adding a dab of flux might help alleviate any pain that might come with bonding two parts without fresh solder. Having a convenient tip shape will help a lot here.

>>1983103
>>1983092
SUCCESS thanks ohm bros. turntable is back up and running. interesting though, before it broke, the orange neon lamp very dim and flicking 24/7 even when the motor was off. now the light stays off until the motor activates (like it is supposed to) so i guess AC voltage was leaking somehow and that probably caused the thermal fuse to overhead and blow

>>1983176

once neon lamps start to flicker, they flicker forever. it's just taking a break from it for a few hours.

>>1983179
its not that it was flickering itself it was that it was drawing about 8V of AC power when the unit was supposed to be off. see webm where it functions correctly now (0V when off, 120V when tonearm activates the motor)

>>1983123
>ideally you'd use some heat-transmitting goo, but of course you dont have any.

tooth paste and vasaline is ghetto thermal paste. its all over youtube fora while back. colgate specifically is what every one showed off

zinc oxide + synthetic motor oil with a little vasaline is what some one else showed off for their mix

baby diaper rash cream is similar to above formula

actual thermal paste is a thing too

sodium hydroxide introduced to silver gives you silver oxide particles which crash out of the sodium hydroxide as a black powder. it turns back into silver when heated to about 550 f. which is low as fuck. you can coat something with it and hit with a lighter. its because silver doesnt like oxygen at all. anyways you can try a controlled slow heat increase in your oven to keep it powder and add that to silicone grease and you have 3/4 of artic thermal paste

fact: oxidised copper is easier to see layout lines on and still etches just fine
fact: it's not good for your callipers to make layout lines atop an anodised aluminium surface

>>1983239
Whew, got it etched before going to sleep. I need to do this more often.

>>1982991
You mean a -jam?

>>1983183
>it was drawing about 8V of AC power when the unit was supposed to be off.

a neon lamp wont light until it gets at least 70Vac, so this observation is prob incorrect.
a more likely scenario is that the on/off switch (activated by moving pickup arm) was always ON, which is why the light was always on, and poss why it overheated. so why is it fixed now? prob coz manhandling it caused the contacts to come unstuck.

Thread topic reminded me of this old gem

>>1983421
youre probably right, either way it was a long-time issue that needed fixing and now its fixed

>>1982991
someone was doing that the other day, weren't they? the green LED transistor guy?

>>1983480
Doesn't ring a bell, was it in a previous general, or somewhere else?

Anyone know of any KiCAD tutorials that are decent?

>>1982278
Not sure if there would be a centrifugal switch inside but maybe low speed isn't enough to flip it because its gummed up?

>>1983491
few threads back, it was probably just a private thing among friends

>>1983551
Not sure if you’ve found shitty tutorials or haven’t watched any yet, but I just watched some 1 hour tutorial and that’s basically all the info I’ve been using. Once you’ve got the workflow of schematic > footprint assigner > layout > traces and vias and such, you can learn anything else as you go. Plus looking up how to use sub-sheets or whatever. If you’re after an advanced tutorial, I’d also be interested if you found one.
t. DIIC14 poster

>>1983574
I’d like to see an advanced competition with all sorts of professional technology employed.

>>1983769
I've been watching some indian tutorials that have been helping. I used KiCAD a long time ago, but I just got a research job offer and one of the things that's in the pipeline of what I'll do is they want me to do is turn some pre-existing DAQ breadboards they have into hats for like arduinos or pi's since I had prior experience with making boards and like getting them through JLCPCB. I just needed a refresher on KiCAD

>>1983778
The one I watched wasn’t Indian. If you already have some experience, you can probably just wing it by hovering over toolbar items, look at the list of hotkeys, that sort of thing. Specific things like sub-sheets or whatever should be looked up in specific tutorials.

Your workplace sounds funky, I always hear of Altium or maybe Eagle being used in the workplace, and I’m surprised to hear that breadboards are being used considering a lot of electronics these days are too fast for one.

>the salvaged pots are log not lin
fuck, well too bad

>>1983867

>>1983867
oh shit i etched the board wrong
oh no
time for scratchy scratchy

Has anyone bought cheap ass load cells off Ali express and was it a good experience

>>1983902
I bought the strain gauges (the ones you have to glue to something). Haven't used them yet, but they're real fucking tiny. IIRC they're supposed to be used with a wheatstone bridge, possibly with two or more linked strain gauges in it, though I'll just make a divider with one, amplify it, and send it into an ADS1115.

Is it acceptable to substitute, say, 5 of those cheap X5R smd caps for a single electrolytic cap, for decoupling purposes?
They'll sit at the input and output of some voltage regulators, both linear and switching, but low power, I think 10uF should be sufficient.
I would like to use JLC's smd assembly service, and all their aluminum electrolytic caps are categorized as 'extended parts' which cost an extra fee.

>>1983894
Finished soldering. Debug time after dinner.

>>1983926
As far as ESR and self resonance and all that shit you could care about, ceramic caps are superior to electrolytics. So long as the capacitance is sufficient, you'll be fine. Though even with lower ESR, they could possibly have lower maximum current values, which you might want to inspect, but I'd guess it to be fine. Be a little wary of voltage levels and spikes, some of those ceramics are made pretty marginally with respect to their breakdown voltage.

>>1983954
DONE

Some debugging required. First, before even finishing soldering, I realised my main pot was wired wrong, as to not give a total gain of 1 across the two inverting amps. That took some scratching and rewiring to fix. Then, after powering it on, I noticed that summing the output and input together looked more like a subtraction, suggesting that one of the two inverting stages wasn't working properly, which also meant bad news for the gain thing. Turns out I'd wired an inverting amp instead as a buffer but with series and parallel resistances (that did nothing), which also took some scraping and rewiring to fix. Then there was a bit of noise, which required three ceramic caps placed about. Also the weird overdrive-like thing (using diodes in a parallel feedback loop) seems to increase its amplitude too much, which isn't ideal but I can't really change it without drastically changing how the circuit functions. And the knobs stick below the base of the PCB. Should be fine as-is, and it will have to be because it's already wrapped up.

>Laughs in 3.5mm

will galvanized screws corrode in dirt if I constantly push current through them ?

>>1984042

you're gonna learn soon enough on your own, but lemme give you a foretaste of what's majorly wrong with this project. in real life, cables get tripped over, things fall down, things hit other things. when these shocks happen in your circuit, whats gonna happen is that parts are gonna fly off with and PCB traces will be ripped off. to prevent, you put your project inside a case, attach all the externals using the bolts they came with, and run wires from them to the PCB.

>>1984277
Don't worry, it's a quick and dirty prototype, with plenty of options to add somewhat of a case around it in the future if wanted. Or pot it in something I guess.
I'm living in a small apartment, with no room for a vice. I don't even have a drill to use one of those existing boxes, though I might nab a broken one from the junk shop and wire it up to a barrel jack. As for panel+pcb mount vs panel+wires, I don't think it's that big of an issue but time will tell. Wires really make things messy, hence why I went for this kind of circuit instead of going for perf-board.

Anyhow, I really like the look of those project boxes made of a solid block, I imagine it's just been bored out from one side but that could make getting the switches and such installed a right pain. I dabbled a bit with that style when I lived with my parents, though to little success.

>>1984042
You could sell boards like that on etsy and make money

>>1984540
They take like 8 hours of labour each, at least how I’m currently painting the footprints and traces and such. If I swapped to using photoresist (or laser ablation of resist) and solder paste in a reflow oven then maybe. Would probably get it faster than any other source of PCBs in this island nation of mine in that case. Don’t have a printer (3D or otherwise) or laser or CNC or whatever though.

Though to design the masks I’d need to find some software that would give me more freedom for designing traces, so likely exporting from KiCAD into a vector program and doing things in there. I’m somewhat comfortable with QCAD.

Would rather partner with a maker space or repair shop or something than sell to hipsters though.

>>1984568
People seem to like the old board layout look, some of the nixie clocks on there have that old board look.

>>1984569
Oh yeah, I could deliberately target some aesthetic like that. Nixies are kinda pricy and VFDs are pretty mundane, but I’ve had my eye on EL displays for a while now. Pain in the ass to multiplex though. A diy EL VU meter might be easy if I make one continuous EL strip with changing capacitance per mm^2 down its length. IIRC Ben from Applied Science made a custom EL display.
Audio effects and such will always be in demand to a certain extent.

>>1984574
How should I get started with audio effects? I know nothing about electronics.

>>1984574
Wait you can do variable length EL? I thought it was an on or off type display and to multiplex it in any way you actually had to have physically separate segments of EL wire?

I've wanted to run an array of IN-9 tubes as a spectrum analyzer but I was planning to run off a low voltage supply with boost converter. The problem is for 10 or more tubes assuming full illumination (worst case) the power draw is on the order of 20-30W and I'm having trouble designing a HV boost converter that can deliver that and keep it from melting. The real issue is the peak primary current is like 15A and my 12V supply can't deliver that nor can I wind a compact ferrite transformer for 15A. IN-9 length is proportional to the current flowing through them so they cannot really be multiplexed. I was looking for a voltage driven alternative. If the length of EL illumination can be varied that might work okay. I could use LEDs but they're boring and I already did a project like that.

>>1984601
make an electra distortion or a bazz fuss

>>1981688
Milling pcbs is super easy, barely an inconvenience
https://www.youtube.com/watch?v=dLbrZtRy8gw

i myself do it all the time
>b-but muh $2 chink fab houses
yeah enjoy waiting 1 month for your 5 boards when you only need one and need it NOW

>>1984720
yeah super easy if you have a cnc mill

>>1984722
and your point is?
you can get a pcb mill for $300 or less
If you can't afford that then you are underage shitter or a poo in loo

>>1984724
>pcb mill
where?

>>1984730
if you are too low iq to use google, then you definitely aren't smart enough to use a mill so forget it and just order your pcbs from china like the other plebs here

>>1984734
No nigger, if I google PCB mills I get 3k $ ones. It seems you are the retard making up lies

>>1984705
Bazz fuss looks beautiful, thanks a bunch.

>>1984736
>type "pcb mill" in ebay
>first result the 3018 CNC for less than 200$

How do I install power under my sink so I can install a garbage disposal? I have no idea where the wires are or anything about electricity at all.

>>1984904
Get an electrician. No trolling, if you are that unaware of electricity, attempting something like that can end up with you dead or major damage to your house.

>>1984868
As someone who fell for the cheap 3018 meme, I can honestly say that in order to get a 3018 to a good level for milling quality, consistent PCBs, you'll have to drop another $150-$200 to get extras for it.
Its a rather steep trial and error system to get everything set up and running, but it does do well once you can zero it in.
$300 is still way too low overall.

>>1984904
ok first things first your going to want to take out a life insurance policy. your going to need to pay in for 2 years and select a benefactor ...

Anyone have recommendations for a good electrical cheat sheet containing basics of everything related to electrical engineering?

It's so easy to forget something basic when you're focused on something else

>>1984945

i saw one at the local library last year. it was over 500 pages.

>>1984634
I'd give the phosphor a variable thickness, such that there's a linear gradient of electric field strength from end to end. I'd drive the EL panel such that the thin end of the panel is being overdriven, the middle is being driven normally (both look similar in brightness because the phosphor is saturated in both cases) and anything above it in the thicker end looks dim. By changing the amplitude, I change the middle point and hence the height at which the VU meter seems to display.

>>1984724
I think I'd rather spend that money on a 3D printer + diode laser addon, and do the laser ablation of etch resist method. For vias and thts I can just drill by hand, or add a drilling addon to the 3D printer.

Someone toss me a circuit schematic so I can practice turning it into a board in KiCAD

>>1985118

>>1984936
>>1984943
I have enough sense to know to turn the power off to the area I'd be working on. I know how to connect wires to a gfci outlet, but there's no socket under the sink and I just don't know where to pull wires from. There's an outlet above the sink, no switch, but I'd have to pretty much cut through behind cabinets to find the wires. Idk if there's an easier way

>>1985123
what do the diodes do

>>1985123
Well it's not pretty, this atleast familiarized me with the process of making the schematic on kicad then making the board.

>>1985250
Oh I shoulda added I guess that I like put them on the same board but then the net thing it generated got it all jumbled up in a weird way so I oriented things on the board the best way I could think to

>>1985250
If those are volume potentiometers, you should use full-sized pots not trimpots. Trimpots are only rated to 50 or so cycles. Also consider using quarter inch headphone jacks for your signal inputs and outputs. Then see how small you can get your circuit, as a challenge, or see how few vias you can use. Don't forget to add ground-fill, for noise reasons.

If you're using SMT transistors you might want to consider using SMT resistors and diodes, if not capacitors too. Or use THT transistors, maybe. If you're just using whatever you have lying about then ignore me.

If you plan on etching yourself, consider making the traces 1mm wide or so. If you want to make it single-sided, don't forget to put the traces on the back of the PCB.

>>1985257
I was looking at the full size pots on mouser but I was having trouble finding the proper footprints for them. I still have to setup the whole like importing footprint thing.

I'm not planning on building it myself, but just using it as a practice bed for designing boards.

>>1985250
d1<>q1<>c1 there has quite the sharp turn.
Remember Anon, 45 degree turns, always.

Heya guise!
OP of the first /ohm/ thread here.
Nice to know this general is already 6 years old hahaha.
Strong general is strong!

I'm gonna buy this kit to get started with electronics. Is there anything else I should get?

>>1985288
https://www.amazon.com/ProTechTrader-Make-Electronics-Component-Educational/dp/B01EKO6FZU/ref=mp_s_a_1_4?dchild=1&keywords=make+electronics&qid=1608859964&sprefix=make+electr&sr=8-4

>>1985288
attiny85 devboard digispark: https://www.aliexpress.com/item/32971847940.html
atmega328p devboard arduino uno r3: https://www.aliexpress.com/item/32680845470.html
atmega328p devboard arduino nano: https://www.aliexpress.com/item/32989224656.html
atmega32u4 devboard arduino pro micro: https://www.aliexpress.com/item/32833347030.html
atmega2560 devboard arduino mega 2560 r3: https://www.aliexpress.com/item/4000946054205.html
stm32 programmer/debugger st-link v2: https://www.aliexpress.com/item/32719963657.html
stm32 STM32F401CCU6/11CEU6 devboard: https://www.aliexpress.com/item/4000103610226.html
stm32 STM32F103C8T6 devboard blackpill: https://www.aliexpress.com/item/32885663343.html
ch340g usb uart 3.3v/5v w/rtscts: https://www.aliexpress.com/item/33020575987.html
gd32v devboard longan nano: https://www.aliexpress.com/item/4000505297604.html
esp8266 devboard nodemcu v3: https://www.aliexpress.com/item/4000055280006.html
esp32-s2 devboard nanoESP32-S2: https://www.aliexpress.com/item/1005001403045642.html
esp32-s2 devboard ESP32-S2-WOOR V1.1: https://www.aliexpress.com/item/1005001562674526.html
ice40 up5k oshw FPGA devboard icesugar 1.5: https://www.aliexpress.com/item/4001201771358.html
nanodla sigrok-compatible oshw logic analyzer: https://www.aliexpress.com/item/4000931572965.html
multimeter an8009: https://www.aliexpress.com/item/4000135799981.html
lm2662 charge-pump voltage inverter: https://www.aliexpress.com/item/1005001639598862.html
txs0108e logic level translator 3.3v<>5v: https://www.aliexpress.com/item/4001278995191.html
ft232h usb jtag uart spi i2c gpio bridge: https://www.aliexpress.com/item/32903296960.html
cp2112 usb i2c bridge: https://www.aliexpress.com/item/1005001546685651.html
1602 16x2 lcd hd44780 w/i2c bridge: https://www.aliexpress.com/item/32763867041.html
ssd1331 96X64 oled spi: https://www.aliexpress.com/item/4000574446702.html
sensor module kit: https://www.aliexpress.com/item/4001174032556.html

>>1985299
Thanks for the help

>>1985272
/ohm/my

>>1981979
>IDK if the shitty little circuits I put on my portfolio are worth anything or if I'm just making a fool out of myself

Stop being an insecure sissy cuck faggot. Do something of value with your valuable time. Stop caring what the retarded horde might think. Do cool shit. Put cool shit on your resume. Stop being a shy little faggotmaster. Be super pro active and enthusiastic about not being a loser anymore (by getting a job) Follow up in all circumstances, thank them for their time, let them know you very interested even if you're not, email, call, always get a contact number, be pro active about being pro active, research the shit out of the company and founder (you have the time because you have no job), if you think you are over doing it, you're not, fix that gay part of your attitude / insecurity, stop being gay.
????
Profit

>>1985264
Making your own footprints is relatively easy, I'd recommend learning to do so. Same for making custom symbols, though that's not quite as useful.

>>1985288
They cannot seriously be charging $100 for that kit. There's only like $20 worth of parts in there if even, what a rip-off.

>>1981979
I brought in some boards I designed along with the schematics and PCB art files to my interview.
I got the job. Mind you I had pretty mediocre grades and not much of any previous work experience in the field.so I felt having boards to show off did a lot for me.

>>1985354
What's the job?

>>1985300
you only need an arduino. Do not trust the stm32/esp jew. If you are getting started you only need resistors, LEDs,capacitors some transistors and a multimeter. Some people here are retarded and recommend everyone to buy the newest fancy wireless, dsp micro controller. That is not a good idea

>>1985288
god damn consoomers...

I want to learn about the various types of FET after learning about transistors. When I was learning about transistors, I followed the logical path:
>N- & P-doped semiconductor, PN junction, NPN transistor
Is there any sort of starting point for FETs? Failing that, is any type of FET (e.g. JFET) considered the "basic" that all the other types stem from?

>>1985740
Knowing how bipolars work is more useful imo. There are two kinds of FETs basically, JFET and MOSFET.

JFET is depletion only, need negative gate-source bias. Usually they're self-biased. JFETs are small signal only, never for power applications, and it's hard to find discrete packages that aren't SMD. They're used more for linear analog applications like amplifiers, not as good as BJTs unless high input impedance is important to you but still way better than MOSFETs. Like all FETs JFETs suffer from bad parameter spread which complicates circuit design.
MOSFETs are used for switching primarily. They can be used as linear amplifiers but they're garbage for it. They're sometimes used in power amplifier output stages thanks to the low Rds(on) but that's about the only saving grace. Parameter spread is god-awful. Worse than JFETs. On top of that they typically have high gate-source and gate-drain capacitance which limits their usefulness in high speed applications or requires the us of gate drivers that can source-sink lots of current very quickly. There are four flavors of MOSFET. N and P channel enhancement and N and P channel depletion. N-channel enhancement requires a positive Vgs to turn ON, P-channel enhancement requires a positive Vgs to turn OFF. N-channel depletion requires a negative Vgs to turn ON (like JFETs), and P-channel depletion is extremely rare, basically nobody makes them and you'll probably never see one in real life but it'd require a negative Vgs to turn OFF should you ever come across one.
Honestly MOSFETs are kind of worthless outside of integrated circuits and power applications like switching power supplies and bridge motor drivers and things of the like.

>>1985758
I forgot to mention there are N and P channel JFETs. They function identically to N and P channel depletion MOSFETs.

>>1981448
Hello hello frens
Today I built a simple relaxation oscillator by using a programmable unijunction transistor, a capacitor and some resistors, but I noticed that the delay between pulses is not stable (like 1.5-3 seconds). Is there a way to make some kind of feedback that stabilizes the pulse frequency? Also I saw that the frequency is very voltage dependent, would a feedback circuit help that too?
In the pic is the circuit, for info, it's from Charles Platt's Make:Electronics.

>have industrial pushbuttons intended for PLCs
can I use these things on arduino or am I SOL?

>>1985824
It's a fucking button. All it does is bridge two contacts. You can use it with anything.

>>1985758
Thanks, that's some good information. I had some JFETs to make an audio amplfiier but I didn't know if the JFET/MOSFET difference was a big difference (e.g. NPN-PNP) or just a small difference (e.g. NPN-Schottky).

>>1985820
All you need is a normal NPN transistor, the resistor from + to the base and a capacitor from the output to the base. An op amp is usually used in place of the transistor but that's just a configuration of transistors.

>>1985832
so you're saying something like this (with the led or whatever at the output)?

>>1985832
or like this?

>>1985820
>Also I saw that the frequency is very voltage dependent, would a feedback circuit help that too?

no. what you're seeing is normal behavior of a PUT. it's not a part that creates repeatable results. so, you only use it when the results dont matter, like maybe you just wanna produce a buzzing sound.

if you want repeatable results, you use something else like the classic 2-transistor relaxation oscillator, or the ubiquitous 555 timer.

>>1985849
For now I will try with a standard NPN transistor then, don't have any op amps at home sadly.
I'm planning to buy lots of them tho, they seem super useful (binary comparators, oscillators, amplifiers, buffers, etc.)

>>1985849
and I will try the 2-transistor oscillator too

>>1985827
can't find any steps on how to do that.

>>1985852
>For now I will try with a standard NPN transistor then,

i dont know of any simple effective way to do a 1-transistor relaxation oscillator. pls ignore person who suggested it.

>>1985857
oh ok, it seemed indeed weird
the 2-transistor one is called astable multivibrator, right? (or is a type of astable multivibrator)

>>1985854

show pic or datasheet for these pushbuttons; someone will tell you where to attach wires to it, since you're such a huge noob.

>>1985858

various names, Astable Multivibrator and Astable Oscillator, relaxation oscillator. lots of hits on google.

>>1985865
yes that's the picture that I had just downloaded too, I will try it thanks

>>1985844
>>1985848
Sorry, when I was thinking of a single transistor I was thinking of an op amp. Although the setup is similar to "sketch2", the op-amp is a configuration of transistors that it probably more similar to >>1985865 than >>1985820.

>>1982557
What do you plan to amp with it?
Btw, kit costs ~$1

>>1981979
I am a designer and I plan to include my DIY projects as a part of Product Design/Prototyping experience if I'll be satisfied with results. There is one project that I'm thinking of that is something like Tascam Portastudio clone, with good delivery (case and interface) this could be great showcase.

>>1981979
My previous job was in a university research lab and there was a point towards the end of a cubesat project where we had to hire new people since a lot of people graduated and there was very important problems that had to be solved.

It ended up being people with shitty GPAs but lots of hobby experience that we hired. The people with like perfect GPAs could hardly even answer or understand basic questions about circuit design and embedded systems, stuff that I (someone who isn't an electrical engineer and only is into this through second hand learning) could even understand.

>>1985917
It's natural really. Most of the high GPA students are merely good at regurgitating things they read in a book, maybe solving a formula or two. The issue is they have no practical design or troubleshooting skills. That's something you really don't learn in school. Labs aren't good enough for developing these skills either, at least I found my labs woefully inadequate. Most students would just rush to complete it following the instructions with no thought as to what the circuitry actually did, just taking measurements. If they needed an answer to a question on the lab put thereto try and make you think they'd just look it up in the book. You build no skills this way.

The entry barrier to electronics is lower than it has ever been, there's really no excuse for not doing projects.

>>1985917
>Cubesat
Unrelated but I was reading about the development of cubesats as a cheaper version of satellite development and I thought it was pretty interesting.

>>1985824
>>1985854
fucking blinkies

>>1985875
Headphone amplifier for electric guitar practice without an amp. The main requirements were ≥1MΩ input impedance, gain variable both below and above 1 (guitar voltage level is similar in magnitude to headphone voltage level), and ability to drive medium impedance headphones (≥16Ω or so). An LM386 can certainly drive the headphones, it can even go down to 8Ω, but its input impedance is only 50kΩ or so, and the gain is only adjustable between 20 and 200. So to use an LM386 IC as a final stage (still not too bad an idea) I'd need another op-amp IC to buffer the signal and handle the sub-1 gain. I decided that it would just be simpler to have a single op-amp IC with reasonably high current driving (30mA or so from the OPA2134), which will be sufficient for listening at a moderate volume. The circuit is what's in this picture.

>>1985949
Thank you! I will definitely need something like this. Want to make similar amp for testing different pedal circuits on a breadboard without cabinet amplifier. Sorry for a noob question: will some boost or preamp pedal make this job?

>>1985972
>Want to make similar amp for testing different pedal circuits on a breadboard without cabinet amplifier
What I've made should work fine for that. It's mainly what it was intended for.
>will some boost or preamp pedal make this job?
I know nothing about existing effects and effect pedals so I couldn't answer that question. But any design like I've made needs to take into account input and output impedances and little else. Noise I guess. In this case I needed gain for the headphones, but otherwise I expect that all of the effects won't effect the gain of the signal much. If you're dealing with a signal directly out of a guitar, you'll need a high input impedance, but if it's out of an effect, it's less of an issue. Transistor amplifier/effect circuits will be more picky about output and input impedances compared to op-amps, it's only 50-250 or so current gain. Compare that to my chosen op-amp, which has 10^13Ω input impedance, and has a closed loop output impedance of 0.01Ω (10Ωopen-loop, 40mA max). That said, transistor circuits can be more versatile for guitar effects, and people prefer their tone, whatever that means.

74LVC1G14
Single Schmitt-trigger inverter

It's supposed to be an astable multivibrator. Am I doing it wight?

>>1985993
Yeah that should work, so long as the output is push-pull.

>>1985996
>so long as the output is push-pull
wat?

>>1985998
Not open-collector, but with both high-side and low-side transistors. A pullup resistor would work, but could give you an uneven duty-cycle.

But considering it's got that oscillator in its datasheet, and says "output source or sink current: ±50mA", it should work just fine.

>>1982593
Superglue is brittle and will crack. Use some silicone, or epoxy, or even some hot glue

>>1986153
I'm personally a huge fan of silicone glue, it's also waterproof and resistant to heat

>>1985993
>>1985996
>>1986007
then why doesn't it blink?

>>1986249
Post picture of your setup.

>>1985917
Where were you doing the cubesat?
Just curious, I was working on one too

>>1986332
A University in Texas, rather not say which one

>>1986007
his circuit looks like its just a led blinker. the led is the bastard telling the current go this way and the hex inverter oscillator isnt stable in that it may not want to oscillate given how finicky they are. the resistor needs to be a pot. some will say thats not the case but you need to be able to adjust it because of the 5 or even 10% deviation any resistor may have.

the led is still a diode. when you put a led on a inductive load that has 2 sets of windings (a small one with a ferrite core thats common on electronics) you can put a 9 volt up to the other side. it will constantly pass maybe 2 volts. 1 thats a transformer now and its accepting dc but only because its small and the wires from the primary and secondary are close. also regardless of how you hook up the 9 volt the led cuts on. the led said this is the direction the current goes. also on some tesla coil designs they use a led to link the circuit to the secondary side with the led facing the secondary. if it flows back at any point it kills the led which probably wont happen the first few times but will eventually. it still works but wont light up because the charge can cross

point is the hex inverter is difficult to maintain with a diode on the output telling it to not oscillate. hook it up to a pizo electric buzzer or small speaker. these will not say current only goes 1 way

>>1986249

an led almost always needs a current limiting resistor in series. yours might've died. or, it's clamping the output voltage so low that it never reaches the upper hysteresis point, so it never flips over.

>>1986249

an led almost always needs a current limiting resistor in series. yours might've died. or, it's clamping the output voltage so low that the cap never charges to the upper hysteresis point, so it never flips over.

>>1981510
This

>>1986153
It's actually surprisingly good, not as brittle as I'd expect.

>>1986249
What's the RC constant and/or set frequency? Do you have a limiting resistor? What voltage are you feeding the schmitt inverter?

I was going to buy some transformers to learn about rectifiers. I've read that I need a centre-tapped transformer for a full bridge rectifier. Can I get away with using that for the half-bridge as well or do I need to buy another type as well?

>>1986446
>I've read that I need a centre-tapped transformer for a full bridge rectifier
Wrong. One form of full-wave rectifier uses a centre-tapped transformer and two diodes, while another form uses just a single AC output (two wires not three) and four diodes. The latter one is what I usually see referred to as a "full bridge rectifier", as the four diodes make a structure similar to other bridges (wheatstone, H).

You don't need transformers to use rectifiers at all, you could rectify any AC source using either single-diode or full-bridge rectifiers, though if your only option is mains you'd probably be better off using a transformer to keep the danger lower.

Or, you know, just simulate them.

How is KiCad in 2020?
I've used Altium, orCAD and Xpedition Enterprise, but I'm intrigued by KiCad because it is FOSS and has a linux version. I heard that it lacked a lot of features. Has this improved any?

>>1986506
>How is KiCad in 2020
Good. The KiCAD 5 update seems to be really consistent. Would recommend. Not sure which features it's missing since I've never tried any of the others, but I know I've never really had troubles. Has a simulator, 3D viewer, microwave design, etc.

>>1981505
stab it with a straw and suck it down like a capri-sun.

I need a 10VDC power supply. I can only seem to find 9V and 12V with the current i need, can I just get a 12V one and splice a resistor into one of the output leads or will this cause issues/housefire?

>>1986596
Get the 12v and get a linear regulator, or a more expensive but better options is get either and use a buck/boost converter depending on what you get.

>>1986596
How much current do you need to supply? A resistor is probably a bad idea, but a couple of diodes might be fine, if not a linear regulator. If it takes more current than those can handle (i.e. more than 1A) you'll want a switching solution.

Often systems that require a voltage that isn't a common logic voltage (5V or 3.3V or whatever) have their own internal voltage regulation hardware, hence it may not matter much at all if the input voltage is off by a volt or two.

>>1986596
12v -> ldo regulator
you should be using regulators in general, switched supplies are noisy as fuck

Which of these oscilloscopes would be the better value for general dicking around or aiding in repairing misc electronics? Top is a Tek 340A ($110) and the bottom is a Tek 2235 ($80).

>>1985250
I shrunk it down a bunch, and added power/gnd fill. This really helped a bunch to get back into KiCAD. Going to try to do something serious now that I might actually build.

>>1986853

obviously top scope is better, since it has processing power, whereas the bottom is old-school pure analog.

>>1986856

much better. honestly, your first effort just screamed out "NOOB!"
still, you have a serious misstep in that large unused area. you gotta find a way to make it disappear, by ending the apartheid between the jack and the circuitry.

>>1986660
noisy switched regulators are noisy. Switched regulators that fit your design requirements, fit your design requirements. Thanks for coming to my TED talk

>>1986857
The apartheid is over. Time to figure out something fun to make, maybe a neat pi or arduino hat or something.

>>1986660
thanks, LDO regulator looks like what I want, current will be 1.25A

>>1986859
haha yeah let me just drop like $30 on a wall wart

>>1986873
Output 2 is probably too close to your trace
What trace width did you choose

Why is it that electronics design at the PCB level is so extremely Windows centric?
Once you get into VLSI, embedded, digital signals or FPGA development Linux is very much mainstream.
With board level design however you just can't even use Linux. The same EDAs don't even support macOS.

I've never seen a more prevalent Windows culture in any other range of available software.

>>1986873
Output 2 is over a trace

>>1986905
>With board level design however you just can't even use Linux.
kicad?

>>1986388
there is a 200 ohm resistor.

>>1986429
like in the drawing: 10k ohm, 100uF, feeding it from 3 to 5, there is a 200ohm resistor between the led and ground.

>>1986978
Yeah but you'd expect at least one EDA company to support Linux/macOS and not have to rely on a community developed open-source EDA.

Maybe this question is better suited to /g/, but here goes.
I'm looking for a smart switch (wifi connected) that can be configured to only momentarily switch rather than flip-flopping between an on and off state. It's for switching a 12V signal used to open or close an automatic fence gate. I'd like to be able to use my phone as opener.

>>1987004
ok

>>1987004
This?

https://www.aliexpress.com/item/1005001604035806.html

>>1986992
bamp

>>1986992
Blue wire going to wrong pin? Row 16 instead of 15?

>>1986992
I don't see a connection between the + end of the 100uF and the input end of the 10k resistor.
Are you sure that's 10k?

>>1987254
Thank you, I'm a blind idiot.

Bros, I just blew my first cap

>>1987128
triggers? try pulling the cap to ground with the transistor.

>>1987128
otherwise, control de charging of the cap with the tranny.

I know this is a pretty basic sqr/tri wave oscillator and I've made it plenty of times before but does anyone know the exact function of the 10K pot? I know I'd have to adjust it to the right value for the whole thing to work but I don't know why I need to. Is it about making sure the differential voltage remains close enough so that it can properly flip its output?

>>1987128

connect pin 3 of monostable to pin 4 of astable. the astable will oscilate for the period of the astable, then be reset.

>>1987128

connect pin 3 of monostable to pin 4 of astable.
the astable will oscilate only for the period of the monostable, then be reset until the next period is started.

>>1987378
Instead of a pot you could just use two 10k or 100k resistors. All that matters is that you have a voltage reference between the two rails. Adjustment shouldn’t be necessary. If you had a split-rail supply you’d just tie those two pins to 0V instead.

Microscopes require bright bulbs to operate correctly, but the bulbs they use are hard to find and expensive. How hard do you think it would be to convert to LED? One issue might be that the original bulbs use significantly more electricity than an LED. It also must positioned in the same spot as the old one. They also have dimmers on them.

Making my own iem cables because fuck paying fat stacks for snake oil.

Am I on the right track by searching for thin 4 core multistranded wire?
Or if there are any audio fellas who know of specific products that'd be cool too.

which chip would you rather marry, tl431 or ne555?

>>1987461
the enclosure may not lend itself to thermal dissipation for leds. is there airflow?

>>1987510
Not really, but it can house a halogen bulb without it overheating so presumably it can do an LED? It would be possible to add airflow by cutting some holes or something, but no fans or anything because that would obviously cause vibrations.

>>1987463
>4 core multistranded wire
For a TRS jack, yes. Though they might actually use Litz wire, multiple enamel wire strands, hence why it's so hard to solder the bastards. I wouldn't bother with that though. For TRRS, you may want 5 strands instead.

>>1987510
>implying an LED will require more thermal dissipation for the same luminous flux than a halogen

>>1987584
a led will fail before it gets a quarter as hot as a halogen.

>>1987584
Ty anon.
I have some silicone wire lying around that's fairly thin, I might use that since it's so soft.

>>1987503
Cd40106

>>1987503
Fuck: TL431
Marry: LTZ1000
Kill: NE555

>>1987616
Yes, and it produces 100 times less heat for the same luminous flux.

>>1987404
Thanks, habibi.

Total beginner here. Planning on following a Black Lion Audio mod for a Bellari RP220 mic pre. Before I order the transformers I want to make sure I understand how to wire them.

pic is the spec sheet for the replacement transformer (Lundahl LL1530), as well as some info from the Black Lion mod sheet, and a pic of the stock transformer that will be replaced.

I'm trying to figure out how the leads on the Lundahl correspond to the leads on the stock transformer, which has no markings or info on it. So far since BLA says the white and yellow are the secondary, and there's a plus sign next to the white lead on the PCB, I assume lead 8 on the Lundahl corresponds to white and lead 6 corresponds to yellow (based on the 1:7 configuration)?

As long as you have the primary and secondary correct, would mixing up the red/black order or the yellow/white order cause any problem other than reversing the polarity of the signal?

>>1987772
>I'm trying to figure out how the leads on the Lundahl correspond to the leads on the stock transformer, which has no markings or info on it. So far since BLA says the white and yellow are the secondary, and there's a plus sign next to the white lead on the PCB, I assume lead 8 on the Lundahl corresponds to white and lead 6 corresponds to yellow (based on the 1:7 configuration)?

That should be correct.

>As long as you have the primary and secondary correct, would mixing up the red/black order or the yellow/white order cause any problem other than reversing the polarity of the signal?

Phase inversion would be the only difference. And I would expect the primary winding black to be - and red to be +.

Is "embedded system" basically anything with any sort of controller/decision making?

If so then are there any special tools you need to design thise, or can i just lay out a PCB in KiCad like usual?

>>1981511
Last two lithium batteries I had to deal with I put in a bucket of water and punctured it.

>>1987796
Cool, thanks

>>1987404
>needed a monostable for a project
>someone randomly posts one
I love when that happens

>>1987876
it's an NE555 circuit, if you're looking for a timer of any sort it's the easiest way to go

>>1987829
An "embedded system" is a computer (CPU, memory, peripherals, often on a single chip) which is embedded within a circuit. It's only function is to control that circuit. In terms of circuit design, the CPU is just another chip. The main difference is that the chip's behaviour isn't fixed; you have to write software for it. "Embedded design" refers primarily to writing the software for an embedded system, although it also encompasses hardware aspects related to interfacing.

In designing the circuit, you usually need to make allowance for programming the embedded computer, either via JTAG or some proprietary interface. Often, the pins used for programming are also used as I/O pins, so you either need to be able to disconnect these from the circuit (e.g. via jumpers) for programming or at least ensure that whatever is connected to those pins won't interfere with the programming operation or be damaged by them (programming flash often involves at least one pin having >20V pulses applied to it).

What am I looking at?
According to my research, these are microcontrollers made by holtek, but they seem so old they aren't listed on their site.
I couldn't find any reference datasheet either. How does this happen? How did the constructor know how to use these? Are the datasheets proprietary?
What does /ohm/ do when they can't find datasheets?

>>1987904
>programming flash often involves at least one pin having >20V pulses applied to it
I wouldn't say often. HV programming is usually only used when it's unaviodable, because of insufficient pin count or something along those lines. Though this only really applies in the stated "the pins used for programming are also used as I/O pins" situation, which I wouldn't say is that common, but certainly can and does happen.
That said, a beginner should be doing projects with somewhat overkill microcontrollers, both in abilities and in pin count. Optimising for package size and cost is really only something that's required for value engineering, though it isn't a bad skill to have.

Arguably there's also the option of programming the MCU once before soldering it in the circuit, never to update the firmware. Not terribly flexible, but it's what I'd do for excessively value engineered circumstances. So long as it's possible to make a programming setup with pogo pins or whatever.

>>1987923
Sometimes you'll find parts that are rebadged or custom runs of them or whatever. Very hard to find datasheets for them. What's it in, and what do you want to do with it? To figure out how it works, I try reverse engineering based off tracing out the pin connections and maybe some dmm/scope/logic analyser measurements. But since it's an MCU, being able to see its datasheet wouldn't actually be very useful, unless you could somehow also extract its source code. If you need to replace it, just finding an MCU with similar pinout (with regards to Vcc, GND, ADCs, etc.) would be sufficient, if not use whatever else and wire it in there from a daughter-board.

ok I want to make an MPPT controller. I just need to periodically control the output voltage so that the output power will be at the maximum value right?

>>1987939
Yes. You could either use a lookup table (not really advised) or manually probe about to see which direction to go in to maximise the power.

>>1987942
but how did it adapt to variance in the power needed from the output? or do you have good literature about the algorithm used? I've searched from Google but most of them are kept behind paywall, fuck that.

>>1987937
It's in a space heater.
My biggest gripe with this space heater is that once it reaches the temperature it's programmed to reach, it turns off until room temperature drops by five fucking celsius. Ideally I wanted to just see if I could dump the program, patch it, then reprogram the chip. I don't have tools for analysis, just a soldering iron, a few wires, and a couple arduino/teensy boards.

>>1987945
MPPTs are used for solar charge controllers, the power "needed" from the output is as much as it can get to charge batteries. The idea is that it's a switch mode power supply that draws whatever current is necessary to get the max power, so you're controlling the voltage indirectly by varying the load current.
So one way to make sure you track the max power point is to keep varying the load up and down from its current load position so you're hovering around the max power point. Then move in the direction that produces higher VA. This is just basic hill climbing and that should be enough because the power curve isn't complicated.

after being a dip peasant for so long i am about to program and solder my first soic8 micro

oh man this is exciting, should i solder it leg by leg, or use two gallons of flux and then melt a bunch of solder into and hope it magically solders the right spots like i see in rossman videos?

>>1987969
Alright, I am starting to understand now. Any literature I could read on this?

>>1987978
google switch mode power supply books, none of these should be hard to find a pdf for. not that i condone piracy, just saying.
also google "mppt application note"

>>1987978
a practical example:
https://ww1.microchip.com/downloads/en/appnotes/00001521a.pdf

>>1987985
>>1987987
thanks lads

>>1987990
I did one before. Basically you need to vary the duty cycle until you find the maxima. But as everything, the devil is in the details.

>>1988021
so you step down the output voltage, check the panel voltage * current, if higher, keep step down until got lower value, and vice versa, am I right?

>>1988053
Usually you start with an open circuit but yeah, usually it is that. Look up the perturb and observe algorithm. The thing you need to decide carefully is how often or when to run the algorithm, you do not want to run that very often so you need to monitor the power for any perturbations (shadows) and trigger it and also every x time units because the sun rises and sets..

>>1987947
Could you just modify its temperature sensor to non-linearly jump to its "on" voltage when it reaches, say, 2C below room temp?
I'm imagining some sort of comparator-based circuit that connects to both the normal temperature input and a reference voltage that's calibrated to be at what the temperature voltage outputs at (room temp - 2).

>>1987947
add a resistor close to the sensor that heats up when the thing is off, adjust current/resistance to choose how fast you want it to turn on

>>1981448
I want to replace a dodgy tact switch: i've sprayed the contact cleaner too often. I measured the package and it's 5mm by 5mm by 3mm I can only find 6mm 4mm and 3mm square tact switches on Aliexpress and ebay.

Am I retarded? do 5mm tact switches exist or do I just squish in a 6mm?

>>1987945
You maintain a variable which is how much current you think the charger should draw from the cells. The actual current drawn is made to oscillate slightly about this value. You monitor the power supplied by the cells (voltage times current). If you get more power at the higher current than the at the lower current, you increase the variable slightly. If you get more power at the lower current, you decrease it. Thus the system stabilises at a point where the power at the two currents is equal. If the cells' parameters change (the optimum-power current drops as the light level drops), the system will adjust itself to track the point of maximum power.

The only parameters involved are the magnitude of the oscillation (it needs to be large enough that you can actually measure the difference in supplied power between the two cases) and the rate at which you change the variable (if you change it too quickly, the system will tend to oscillate about the maximum power point rather than stabilising at it, and will respond to noise in the power measurement).

>>1987904
Thanks anon

>>1988097
there are thousands of different tactile switch products, ali/ebay only sell a popular subset of them. i'd find a replacement on digikey if it's worth the $5 shipping but you might also manage to solder a larger switch on there if it fits in whatever product packaging.

>>1988124
Yea, now I understand that all the controller should do is to raise or lower duty cycle so the PV's VA is the highest regardless of load.

>>1988144
Not really. It is not because of the load (only) the main thing is the panel. The load usually is something that was made to consume X amounts of power.

>>1988128
>digikey
why do you like to throw money away?
buy from chinks ffs

>>1988280
lcsc's shipping isn't any cheaper and beggars can't be choosers on ali.

Whats a good microcontroller to graduate to after arguing or raspberry pi if you want to make more serious stuff?

>>1988377
You pick the cheapest that is suitable for your application and that you know how to program. There's no one size fits all micro.

>>1988377
Probably the 8-bit avr micros. You can do quite a lot with them. After that probably look into the stm32 micros. The higher tier models with the DSP extension are commonly used in building guitar pedals/eurorack modules to generate signals and real-time effects.
But you should know that there's a microcontroller general on this board too. I'm too lazy to link it, just search the catalog.

>>1988377
I'm fond of the stm32. More features for same or better price than a lot of 8 bit micros.

>>1988377
imo get a very simple PIC or AVR and program in assembly for at least one project. arduino is great but it gives you bad habits.

>>1987945
Just measure current and voltage, and vary SMPS duty-cycle until the multiple of those two is maximised. Buck converter is probably best, but you could also go boost or buck-boost. As well as what's basically an LC low-pass filter on the output of the buck, you'll also want one on the input, just after the solar panel. You'll probably want to integrate battery overcurrent and overvoltage conditions (requiring voltage and current measurement of the batteries themselves, as well as the solar panel), MPPTs are meant to be used when the solar output current is under the maximum input current for your battery (or battery + load, if the load is active). When the MPPT is able to output more current than your battery (or battery + load) wants, you step away from MPPT in order to preserve an acceptable battery charge curve.

>>1988381
>There's no one size fits all micro
32 bit guys like the GD32V are cheap enough for the performance that they provide that they're close enough. As I said in an earlier post, unless you're all about value engineering for mass production, you really don't need to skimp out on MCUs as even powerful ones aren't very expensive. Though learning to cram code in an underpowered package is still a valuable skill to some extent. Same for writing in assembly.

>>1988128
cheers.

>>1988377
mbed with STM32

>>1988419
I was planning just to attach a BMS to the battery pack, will this work?

My new years resolution is to make shit

>>1988662
You're going to raise electronic chickens?

>>1988673
Yes
The eggs they lay will have back doors for every major intelligence agency in the world

>>1988642
probably, so long as the bms does both charge and discharge protection

[math]2^{2}[/math]

>

>>1988748
<

So unlike a BJT where its "active" state allows current to flow from emitter to collector, a JFET
stops current flowing when "active" (at least, when the gate voltage reaches the "pinch voltage")? So the BJT and JFET are not only opposite in gate control (current vs voltage) but also in "switch on / switch off" function?

>>1988759

not exactly. read this for fun, to see how Vgs can be made negative so that it can work: wwwDOTelectronics-tutorialsDOTws/amplifier/amp_3.html

>>1988722
I see, thanks a lot

>>1988088
Good idea. I don't have an MCU with an analog output but I can probably make the heater think it's freezing by outputing 0V, and output 5v when I'm within 1 degree of my target temperature.
Pic is the probe I found inside. Do these have typical operating characteristics?

>>1988768
see>>1988089

>>1988089
>that heats up when the thing is off
how? with magic?

>>1988841
>>1988933
Also making the sensor hotter will just keep the heater off, as it will think the room is higher than the target temperature.

>>1988934
No you have to use a resistor with negative resistance

>>1988662
Make:Electronics and its encyclopedias of components are very good too

I'm learning about OTAs and wanted to throw together a quick & basic VCA. Would this work? I would hope that I could get away with not biasing the inputs since it's just a test.

>>1989165
Forgot to mention that the signal input is just a 12V DC square wave I made from an astable 555.

is ts100 good
i bought one

>>1989370
lmao
tell me if it is, I need an upgrade from this chinkstick

>>1989421
ya its good

>>1989370
>>1989421
but a T12 is a better idea unless you need something portable

I wanna replace this PS3 controller battery with something better than an ebay clone. I found these on adafruit, but they're lipos, not regular li-ions.

https://www.adafruit.com/product/2011

Are they not compatible? They're both 3.7v, they both have protection circuitry, and the adafruit part has a higher charge current tolerance at 0.5A. Hell, doesn't the LIP in the original battery's model number imply lithium-polymer?

What should I look out for when buying a stepper motor & driver? I saw a bunch of these old steppers ripped from photocopiers sold for $3. Are they usable or do they have some kind of quirk to them?

Alternatively, can I somehow have a normal motor turn a specific amount (like 1.5 deg) and stop at a full revolution?

>>1989485
Should be fine, they're similar enough.

Another question about MPPT guys: What will happen if the MPPT is connected to the battery AND the load? How do the MPPT know when to stop charging if the battery is full but a load is still connected?

>>1989573
It depends on the type of load you've got. If the solar output current is less than the load or the battery can take as a maximum, then there's nothing to worry about. But in the event that the battery is nearing full charge, you'll need more circuitry to ensure no overcharging happens. This should be a part of the MPPT feedback loop. If your load isn't current sensitive (like a large heating element) then that's that, if the load is current sensitive then you'll want overcurrent feedback to the MPPT going from the load too.

If you're programming all that shit with an MCU then you just need to consider a variety of situations and ensure that the program fits all of them with a series of conditionals. Conditionals that ensure MPPT is maintained when the batteries/load need it, and leaned away from when maximum solar output power is greater than the needs.

>>1989165
did you use designspark to make this schematic?

>>1989580
>But in the event that the battery is nearing full charge, you'll need more circuitry to ensure no overcharging happens
if I keep the maximum charging voltage to let's say 1S batt to 4.1v wouldn't it never going to overcharge the battery provided that the max current I supplied is lower than the maximum batt charging current? My load is probably going to just be an inverter.

>>1989678
KiCad

>>1981511
>what do normal people do
Take it to a shooting range.

>>1989485
>https://www.adafruit.com/product/2011
12 dollars for a battery
fuck adafruit

>>1989834
>https://www.adafruit.com/product/2011
>tfw it's 8USD in my cunt
>tfw it's the same price for a 21700 4Ah batt
wtf?

Bump limits been reached, here's a new thread I got for you:
>>1989950
>>1989950
>>1989950
>>1989950
>>1989950

The receipt is in the box.

>>1986332
>>1986355
I was also on a cube-sat project, but not in Texas