Thread that glitched:>>2970026>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.Read the datasheet.>OP source:https://github.com/74HC14/ohmOPbake at page 10, post in old thread>Comprehensive list of electronics resources:https://github.com/kitspace/awesome-electronics>Project ideas:https://hackaday.iohttps://instructables.com/tag/type-id/category-technology/https://adafruit.comhttps://makezine.com/category/electronics/>Books:https://libgen.is/>Principles (by increasing skill level):Mims III, Getting Started in ElectronicsGeier, How to Diagnose & Fix Everything ElectronicKybett & Boysen, All New Electronics Self-Teaching GuideScherz & Monk, Practical Electronics for InventorsHorowitz and Hill, The Art of Electronics>Recommended software tools:KiCAD 6+CircuitmakerLogisim Evolution>Recommended Components/equipment:OctopartLCSCeBay/AliExpress sellers, for component assortments/sample kits (caveat emptor)Local independent electronics distributorsladyada.net/library/procure/hobbyist.html>Most relevant YouTube channels:EEVblogW2AEWMoritz Klein>microcontroller specific problems?>>>/diy/mcg>I have junk, what do?Shitcan it>consumer product support or PC building?>>>/g/>household/premises wiring?More rules-driven than engineering, try /qtddtot/ or sparky general first>antigravity and/or overunity?Go away
Oh I'm retarded
i finished designing the digital logic for a tile-based graphics circuit somewhere in power between an NES and SNESi want to realize it (or at least some of it or an adaptation of it) in both FPGA (easy) and TTL (a lot more work)wish me luck
are beginner kits a meme? i feel like electronics is something i have to feel instead of just reading books
>>2975984indeed, electronics are definitely best learned when applying what you read in a book on a benchthere are so many parts that if you are a beginner these kinds of kits are just fine to get you going
>>2975984Arduino kits that send you into programming without the foundational intuition of voltage sources and current flow are not recommended. Even once you’ve got that intuition, it’s probably best to experiment with some basics of analogue electronics, like learning why an NPN transistor is usually used with its emitter to ground, how capacitors and resistors shape square waves, that sort of thing. Then you can go into the programming side of things if you really want to turn a hands on hobby into code-monkeying for some reason. You won’t use 90% of the stuff in those kits in projects, but getting experience on using its arbitrary modules will make you faster at designing novel projects with novel sensors and interfaces.
>>2975984>i feel like electronics is something i have to feelfeelings only come into play after you've gained enough experience to intuit a solutionbefore that comes 80 years of study, applying cold hard logic, and thousands of burnt fingers on hot tubes
For the anon who was wondering about the triangle wave generator from The Art. Page 239.
>>2976010You used those values for R3 and R2? But your triangle wave in your picture is basically going from 0V to 5V if I’m reading the V/div at the bottom correctly.
>>2976013No, I tried a 2:1 ratio instead of a 5:1, and overall values were tweaked to get a higher output frequency according to the equations presented.
can anyone recommend a reflow oven? I only need one large enough for single eurocards. picrel is the cheapest I could find that still seems decent, but it's 1600€ + VAT which seems a bit steep. plus it's bigger than what I need
>>2976033lol a rebranded version of the same oven is available from conrad for just over 1000€ + VAT. and of course aliexpress have ovens for like 300€. but then it will probably take many moons to arrive
Tore everything down and rebuilt it. It doesn't present any issue now. The mysteries of breadboarding. Now my fully analog PWM H-bridge controller works! Damn I'm happy.Speaking of something completely different, what's a good hobby grade desktop DMM? I have the Aneng AN8009, it works fine, it's just not great for desk use since it's light and the stand sucks, so at the smallest tug it falls down.
About to tear my Les Paul apart and rewire it to my liking.Pots are 500k logarithmic with a push/pull DPDT switch ("Polarity Neck" and Bridge). Capacitor is whatever was originally in there (22 nF I think).
>>2976037looking a bit more at the T-962 it seems it has numerous problems>masking tape for electrical insulation>uneven heat distribution>actual temp can be 20°C above set point>buttons aren't debounced>poor groundingthere are ways to modify it to make it decent. not sure if that's worth my time
>>2976140lol the poor thermal control is because the cold junction for the oven's thermocouple is simply assumed to be 20°C. a firmware upgrade + DS18B20 fixes this. someone could make a bit of money selling these in upgraded form for maybe 500€
>>2976140is this whole photo ai generated? the background definitely is.why?
>>2976146They lacked a stock photo of it in a lab?
>>2976146lol didn't notice that. I just grabbed the first picture I foundanyway I found a guy on youtube (Jerry Walker) who has been working on these ovens to improve their thermal control. especially the evenness of the heating. the thing that made the biggest difference was installing a fan that mixes the air around insidenow that I think about it, the RF100 >>2976033 looks suspiciously similar to the T962 in its general layout. if it also uses four IR lamps to heat the boards then it will have the same issue and one might as well get the 962
>>2976158>a fan that mixes the air around insideJust checked out his part 3 video, seems like he's bolted a little motor to the other side of a panel with a makeshift fan blade on the end of its shaft. Seems to me that a thin sheet of stainless isn't enough to stop the motor itself getting up past 70C, I'd guess it would even go up past 120C. Instead I'd want to use a significantly longer shaft, with at least 20mm and some insulation between the oven and the motor. Maybe a little brushless fan aimed at the motor too.
>>2975961Have I not found it, or has no one been man enough to build a good, easily reproducible (no carpentry required) open source bass/guitar amp? I feel like it shouldn't be that hard>get some big speaker cone for $30 off amazon or whatever>3d print some crappy enclosure>stick it together>use a gainclone or similar for power amplification>add robust EQ to deal with the shitty cabinetWhat am I missing?
>>2976166Particle board and mdf have pretty good acoustic properties for speaker enclosures.To solid-fill PLA case is going to take days man, plus there’s a good chance that the heat will melt the PLA.I guess if the only tool you have us a 3d printer then every problem looks like a yoda miniature.
>>2976140> infra redThat’s one of the stupidest ideas I ever heard.The IR will bounce off the shiny traces, but over heat the PCB.
>>2976171Ok, get some 1ft sq acrylic sheets or something and print some brackets to hold it together. Dump a bunch of hot glue over the boundaries
>>2976173It's still easier to use some kind of wood.Also I just saw a bass amp free for parts the other day. It would be way easier to frankenstein something like that.
>>2976166If anything you'd buy a cheap ikea container to put the amp inside. Or use a guitar preamplifier circuit plugged into any old (portable) speaker with an aux input. You could put all your tone and gain knobs on the preamp, and rely on the chinese for cutting down the costs of the power amp + speaker + enclosure setup. Not like it has to look like a real guitar amp after all.>>2976172It's probably 1-3um infrared, some metals definitely have non-trivial absorption outside the visible range. But I suspect you're at least half right, seems like convective soldering would not only produce more even heating, but offer more accurate temperature sensing too. Maybe air friers truly are the best.
>>2976172>>2976178Do you two understand what infrared radiation is.
>>2976182If those elements are hot enough to be glowing, they’re at least 500C. That means their peak wavelength is 3.5um or shorter. If you aim an infrared camera at something at room temperature, it’s measuring that temperature by radiation about 10um in wavelength. Metal objects often just reflect infrared radiation (i.e. they have high reflectivity and therefore low emissivity/absorbtivity), so you’ll often need to put a piece of black tape on them to get a proper reading off them. Pic related, while I couldn’t find any data for tin specifically, it seems a trend that metals become more reflective at longer wavelengths, extending well past 4um. If tin metal is highly reflective in the visible light as these other metals are, I would assume it to also be highly reflective in the medium wave infrared ranges, and hence be a poor candidate for heating via infrared radiation.That said, ceramic stovetops work by transferring infrared radiation into the base of a pot which is often polished stainless steel, so as they heat up they may become less reflective and more absorptive.I still stand by convective heating being better though.
>>2976190Actually GPT is telling me tin has a reflectivity of only 50% at 3.5um. No source. I guess that works ok, but it’s also saying that an epoxy SMD package will have a reflectivity of only 10% so your components are going to heat up almost twice as quickly as your solder. Considering our element is at like 500C and the temperature is limited by transfer speed, that will result in the components getting significantly hotter than the solder, as opposed to having an element at 250C and having temperature limited by thermal equilibrium (this would probably take ages with radiation alone unless you had a large element area and lenses).
>>2976192I autistically did the calculations for a herbal equilibrium infrared heater. You’d want maybe 24W per square centimetre to reflow a circuit board at 220C from ambient temperature in 5 seconds (calculated from heat capacities), accounting for 50% absorptivity thats 48W. As per the Stefan-Boltzmann law, a 220C blackbody will emit about 1000W per square metre, so if you could focus down the radiation from a 20x22cm blackbody onto just one square centimetre of PCB, that would give you your 48W. Maybe a 30x30cm area would be a bit more useful, but if you could adjust the area by moving the board up and down the focal-plane or adjusting the focusing elements you could cover small areas and large areas all the same. Practically you’d have a fixed thin-film heating element (maybe inductively heated sheet metal with a coating) and a mostly fixed series of parabolic thermal mirrors to focus the infrared to a point where you can put a PCB under it by hand. With some shutters in front of it I guess. And a temperature controller for the element. Seems unreasonably practical.
>>2976010thanks for posting the reference anon. I understand now how the wave stays centered around zero.I was trying to imagine a way to have a triangle oscillator where the wave cycle was controlled by some external square wave, but I think then it really would drift away from the zero point over time as the charge/discharge cycles might not be perfectly equivalent.
>>2976172it very much depends. IR bounces off of certain materials and not others. it also depends on surface roughness. a shiny gold surface has very low emissivity. rough aluminium not so much. it clearly works well enough, except for the uneven heating due to the design of the chamber
>>2975961Dumb question but, what can you do in this hobby? what can you do with your electronic knowledge?it seems like it is a wide field and you could do anything. but once you get into it making any simple project seemto be expensive on parts and time, so in the end you do useless gadgets and strat projects you'll never end.
>>2976210You could have a bleed resistor on the integrator, the harder part is if you want the amplitude to remain constant regardless of input frequency. You’d either need some sort of AGC or a PLL.
>>2976166All kinds of cabinet kits out there and empty cabinets for sale. Yeah, hobbies get expensive. Do you get 3d printing filament for free or something?
>>2976182I have a non-convective toaster oven. It’s crap.I tried using it to cook something and it just burns the outside to charcoal while leaving the inside raw.It works better if you put aluminum foil on top of it so the light isn’t shining right on the the thing.I use it every day for over a decade.It’s crap, and this thing is probably crap too.
>>2976270There’s a group of people that build and advocate using concrete speaker enclosures, i thought that was a good idea.
>>2976290It actually is as long as you don't plan on moving it often.
>>2976256>Dumb question but, what can you do in this hobby? what can you do with your electronic knowledge?build electronics gadgetsmore seriously, the depends on if you have any other hobbies. for example, if you're a guitarist then you can build guitar pedals. being able to debug and fix broken electronics is also useful
>>2976309>what can you do in this hobby?build a fully functional robot girlfriend>depends on if you have any other hobbieslosing your virginity before 40
>>2976256>Dub question but, what can you do in any hobby? What can you do with your specialist knowledge?>it seems like in any wide field you could do anything. but once you get into it making any simple project seemto be expensive on parts and time, so in the end you do useless gadgets and strat projects you'll never endLet me reveal you the truth about why people do anything: because we want and we like. I know it's hard to overcome the utilitarian mindset because it's literally what the ruling class (rich people, especially billionaires) wants you to live by because it makes you a better drone, but once you realize you don't have to produce anything useful and nobody is judging you for what you do, you'll be free to explore your interests. In a sense hobbies like electronics are closer to art than a mean to a financial gain.
>>2976256It’s often cheap on parts (compared to car modding, for example) but can definitely be time consuming. But it’s one of the few hobbies where one can create a project that rivals professional equipment, maybe even eclipsing it in some cases. But then it won’t just be electronics, rather it will also have aspects of mechanical design, maybe also optical, thermal, fluid, etc.
>>2975961I have tried wick, sucktion solder and heat gun. The joystick is stuck to the PCB still. Does anyone know a way to tear apart the joystick to get it off the board?
>>2976322This is gonna sound crazy, but add more solder and then suck it again. The idea is to seal the hole so you get better capillary action and surface tension adhesion with the old solder. It helps to use a short piece of silicone tubing attached to the end of the sucker because it gets a better seal around the joint and can handle hot temps for s short duration without melting. Lastly, don't use a conical tip on your iron. A chisel tip transfers heat more efficiently and works better with the sucker. Good luck.
>>2976322get a desoldering gun
>>2976336I have that cheap pos off amazon and it worked 50/50
>>2976322First note which pad(s) are connected to the ground plane. Wind thick (1mm) solid core copper wire around the legs of the stick, and apply solder to each joint, ideally such that the grounded pins are near the middle of the wire. Then crank your iron up and apply heat to the middle of the wire to pump heat through the wire and into all the pads at once. Might take a minute of heat. Make sure you’ve got decent work holding, don’t want a 300C PCB or analog stick falling into your lap.
>>2976322>anyone know a way to tear apart the joystickyou've hit upon the answerif your desoldering game is weak, the sure-fire solution is to destroy the component, then push the individual pins out with a stainless needlea sharp side cutter, and a gentle touch, will do the job
>>2976313you got me wrong or I explained myself poorly. it's a hobby, go enjoy it, I play guitar which is inherently not productive. but you always do stuff towards an end. I don't take the guitar and smash random notes, I try to take on a riff or a song.same thing, you practice electronics, you are doing some stuff. I'm interested on what kind of stuff can you do.>>2976309this anon told me about guitar pedals and I'll look into it, but I went to youtube and I saw stuff like making a lightbulb work with a button. amazing.also as I said I'd like to know opinions because this hobby looks like you can do a lot of things but then you are really trapped on shitty projects and useless gadgets. let me explain.>I will make a calculator>fuck, this will take some time to understand and design.>ok so I have to spend 10$ on parts to make the same stuff a 5$ calculator does.>also it's ugly and does not work>project number 9012 gets stall
>>2976409making a calculator is a good excuse to learn how microcontrollers workguitar pedals allow you to learn how analog filters work. just a simple low-pass pedal with a knob will get you far I think, especially if you design it yourself. other silly things you can do is put in active components that cause distortion. like diodes, or transistors with improper bias. things like that. you can play around a lot with a breadboard and cheap simple parts. most advanced part you might need is an opamp
>>2976372I got to 5 pins left of 1 of the two controllers now. Unlike the first one the second one will need tweezers but it was like 1am by the time I got to it. The pins are kinda held in not by solder but by the tight clearances of the pins for the frame around the joystick.
>>2976158>if it also uses four IR lamps to heat the boards then it will have the same issue and one might as well get the 962https://www.fortex.co.uk/product/rf100-smt-hot-air-low-cost-reflow-oven/>Utilises 4 x Infrared quartz heating elementsand the Bungard HOTAIR 300 looks identical. I suspect both companies have just bought Puhui gear, repainted them and slapped new labels on. maybe if they were open about this and if they've done any upgrades, like Elektor does, then I'd be inclined to buy from them. so yeah, Puhui it is. honestly Puhui should just sell an upgraded version of the 962 for maybe 20% more and nip all this in the bud. they could even use the free replacement firmware
>>2976409>what kind of stuff can you doTo me it's not what I can do, but what I can learn, often just for learning sake. Like any engineering field, there's a whole world to explore and projects are just a way to direct the exploration, more than an end in themselves. My current project is a toy to better understand PID controllers, breadboarding has gone all right, now it's CAD time for a fun enclosure and mechanical integration. Next maybe radio stuff, because to me it's the closest thing to literal magic and I want to know more.
I won't be annoying here anymore. just to leave something, people here might enjoy this game.I tried it and IMO it really lacks explanations, but if you already know electronics it may suit you.
>>2976448I had that game in my wishlist since forever, but I refrained from buying it because>early accessI was under the impression it was more oriented towards programming than anything else. Like Zachtronics' SHENZEN I/O, sure it's electronics and microcontrollers in the surface, but it's basically a programming puzzle game like any other Zachtronics game.
>>2976465Something like Factorio or GTNH is probably about as close as you can get to circuit design and routing. It doesn’t have ideas of noise or interference or impedance matching or length matching, so the routing challenge is much less of an issue than the design challenge, and even that’s half trivialised by wikis and tutorials.
Are there any good vidya for learning electronics?
>>2976484shenzen io?
Would this scratch preven this from working?
>>2976535
>>2976484Best you’ll get is learning digital logic, minecraft (especially modded) can do that decently but it’s not part of a gameplay loop, there might be other games that do something more integrated with the gameplay loop. Imagine having to build a computer to decode encrypted messages of increasing complexity, or to triangulate radio and seismic signals, or calculate artillery and missile trajectories. Ideally you’d be incentivised to build specialised calculating machines with task-specific designs and all calculations done in hardware, as opposed to just slapping an ALU on an instruction decoder and some memory and programming everything. Doing analogue operations (especially for any integration) might be the way to go, but mixing analogue and digital calculation isn’t straightforward. But damn do I want to perform a fully analogue fourier transform.>>2976530See earlier posts, it is basically just an assembly programming game with a smattering of topology optimisation and part selection. Also a really addicting solitaire variant. Maybe it’s an accurate reflection of some EE jobs, but not at all representative of many facets of electronics.>>2976538The scratch next to the soldered pad in the middle? No.
>>2976539>See earlier posts, it is basically just an assembly programming game with a smattering of topology optimisation and part selection. Also a really addicting solitaire variant. Maybe it’s an accurate reflection of some EE jobs, but not at all representative of many facets of electronics.maybe "toob amp designer" could be an interesting other side of the industry to make a game out of
>>2976535Only if it's shorting that (probably ground) plane to the pad
>>2976544Imagine the game having really shitty FPS despite not having very good graphics, turns out it’s running spice under the hood.
>>2976555just run spice in a separate thread lmaoactually you could turn that into a game mechanic. like as you progress you can put more spice threads in the background evaluating designs
>>2976552>>2976539I could have ordered another ebay wmr controller set for what I've spent trying to desolder.Anyways I ordered a micro needle for my unit to try the force some out
Not sure if this is the right place to ask this. I am a 3rd year electrical engineering student eventually interested in going into the embedded track (currently taking core classes.) I want to land an internship doing something embedded, and my ideal path is to go into the industry directly after graduating. I'll note that I checked out the project idea websites and the ohmOP github. However, I am not sure what kind of projects I can do in my spare time to make myself attractive to potential employers for embedded internships. Does anyone have specific recommendations in general for someone who is interested in this path?
>>2976586No, but chances are you want something that translates well to the industry. With embedded, that means having specific experience with the microcontroller families used in industry, maybe also PLCs, idk. You may also want to get some experience with an RTOS and programming robust state machines. I’d also look into EMC; make some powerful sources of broadband magnetic and electric field noise and see how far you can push a project’s noise immunity. I’d consider getting experience with industrial communication protocols like RS485, maybe also CAN or Ethernet. Try other industrial practical things like motor driving and advanced feedback loops. I’m not sure if experience with computer vision and other neural network stuff would be appealing, but I suspect even in old industrial applications it’s slowly creeping in, like for production line fault flagging. Same for RFID and wireless technologies.Is there an industry in particular you’d want to head into?
>>2976591>NoNo as in that this is not the right place to ask? Where would be the place to ask? Gotcha, I see. Thank you, I will keep that in mind. I was researching CAN as a part of a project I was a part of.As for industries, I am interested in primarily the semiconductor/silicon industry. However, I am open to looking into consumer technology, medical stuff, automotive, and embedded stuff.
>>2976593The "No" was for "Does anyone have specific recommendations in general for someone who is interested in this path?", because I'm attempting the entrepreneurial route. I say that but I'm really just building projects in my free time until I have the experience and confidence to make something akin to a product.Arguably someone on the microcontroller general might be in the industry, but if you hang around long enough on either general you'll probably get someone with experience responding. As in half a week.I'd just get making any projects that push the envelope of your experience and skill. Make the scope of each project limited, feature creep is the bane of a one-man-band.
Sorry for the novice question, but what kind of component is this? Marked on the PCB as a diode despite looking like a resistor. There are more of them on the board except with different color codes, but all marked as diodes.
https://nepp.nasa.gov/whisker/index.htmli kinda found this whole page to be funnythe whole presentation almost reads like /x/ or /sci/ schizopost or am i retarded enough to consider anything funny
>>2976604measure it with a multimeter
>>2976611Resistance is 11.5k ohms one way and 6.56k when I switch the multimeter leads. Also has this symbol on the other side of the PCB. That should indicate a zener diode, right?
>>2976612Forgot pic.
>>2976612you might want to lift one of the legstesting whether it's a zener is a bit more involved but not difficult. put a resistor in series with it (like 10k or so) and put as much voltage as you dare across
>>2976614Understood. But the symbol does imply that it should be a zener, doesn't it? I was mainly just curious because I had never seen a diode that looks like that before.
>>2976616oh yeah I didn't notice the symbol. yeah that should be a Zener. strange package indeedan update on my reflow oven investigations: the T-937 is a better investment because the T-962 cannot do lead-free. this is apparently the word of Puhui themselves
>>2976465>more oriented towards programming than anything elseI've played through all of Turing Complete and the programming only comes in the final section. At that point, you are manually entering the binary to build opcodes for a CPU you built yourself from logic gates. So you essentially have to make your own assembly language and then write programs to solve some of the classic CS problems like towers of Hanoi, etc.I felt like this game was a really accessible introduction to how a basic CPU works, it introduces concepts like the stack, ALU, etc. Would recommend. It never felt like early access to me at all.
>>2975961i'm trying to design a small battery charger, basically buck down 20V USB-C to whatever voltage and current required. i need to prevent:1) reverse current flow into the buck converter with correct battery polarity2) reverse current flow due to incorrect battery polaritydoes this require a minimum of three FETs? i figure i need back-to-back FETs to address the first case, otherwise there is body diode bypass current. in the second case, i can't just rely on the high side back-to-back FETs, can i? a battery hooked up with incorrect polarity would allow current to flow through ground into my ICs and through any ground-connected passives.
>>2976654so i could not rely on something like >>2976654 this and i would instead need something like what i have attached here?
>>2976613
>>2976654I don’t see why the two transistors at the top can’t protect in both cases. It’s the voltage as measured by that differential op-amp that will tell you that the battery is backwards anyhow, right? But I’d do the calculations to see what voltages will be at the amplifier’s terminals at a variety of situations, especially for if the power supply is only putting out 5V.Your buck converter might even be able to handle a higher voltage at its output than its input anyhow, I think that’s worth testing if the datasheet doesn’t say.Also, your error amplifiers’ integral gains are really high, might want to tame them with resistor across each capacitor. A bit of differential gain to prevent oscillation might help too, idk.I’d also strongly consider some method of charge termination, to shut off the output once the current drops below a certain level. Be that with a comparator, or with DACs controlled by an MCU. Leaving a battery at full charging voltage for an extended time is bad for its longevity.
>>2976693>charge terminationi plan on doing this in software since this is going to be NiMH (probably -dv/dt termination) and LiPo (0.1C termination) dual use. i do have latching hardware level protection for reverse polarity, over current, and over voltage.>I don’t see why the two transistors at the top can’t protect in both cases.if i insert a battery with reverse polarity, won't the current flow through R19, through GND, and then risk flowing backwards through all of my ICs or passives? i mean it might be okay but i don't want to risk blowing shit up.
messing with building a tiny Hartley oscillator. it's going to use surface mount 0402 parts, and such coils are lossy, so I built a little circuit to test what to do when using coils with ~5 Ohm ESR. transistor is a 2N7000 N-channel MOSFET. two points stick out:>proper bias (upper red wire goes to a fixed 2.2V supply)>short the emitter degeneration resistor (lower red wire)the downside of shorting the emitter is that the waveform isn't a nice sine. it's probably possible to fiddle more with it, using a suitable small value between 0-100 Ohmone thing I discovered is that it's possible to use quite low drive so long as the bias is separate. I can drive the oscillator at 0.7 V if I use a separate 2.2V bias (via 100 kOhm)
>>2976704Yeah you definitely need reverse polarity protection if U1 can’t handle a negative voltage at its output (it probably can’t), but for the “reverse current flow into the buck converter with correct battery polarity” you may not have to worry. With a 20V input, it might be able to have 25V presented to its output without it flowing back and damaging anything. It might be fine even if it does flow back, the boost converter in the power bank will block any reverse current.It’s also an option to put a conventional diode inline with the charging current path, but inside the feedback loop so the voltage drop is taken into account by the switching controller. You could also put a diode across the output to short any reverse battery’s current, ideally blowing an output fuse. Even if you have that reverse-polarity-protection FET, I’d probably still do this.
>>2976586You should be talking to employers now, learning about their companies. In year 4 you should be interviewing for positions post graduation, so you can jump into a new job, otherwise there's a weird limbo state you'll be stuck in sitting around worrying. In this field you want to be useful and able to do things, that's what makes us employable. Just build something that sticks out to you
Gonna try some nickel plating tomorrow. Bought some alibay nickel strips intended for battery spot-welding, I’m electrochemically dissolving them in white vinegar right now. They seem to be pure enough to dissolve well, but it’s taking a while and there is a bit of residue left at the bottom of the beaker as the anode dissolves. Using concentrated cleaning vinegar would probably be a lot faster, maybe then I’d be sitting at 3V with high efficiency, instead of pushing 12V to get 0.2A.Apparently thiourea is a brightener to improve the surface finish of plated nickel, I’ve got some thiourea lying about in the silver polish I used for tin plating of copper a while back, that might be interesting to mess about with.I plan on plating the aluminium atop a knob and the copper of an FR4 faceplate for Amy audio mixer, to make them better match the lustre of the chrome-plated or stainless button and jacks.
Greetings fellas, I've stopped with electronics for a couple years but I've been bitten by the bug again.I need to record multiple audio signals in sync. Does anyone have info on off the shelf solutions for this? I'm a bit rusty with the digital side of things, so sure I can get 10 DACs, but getting them into the computar is another story.
>>2976826Get an external 10-channel mixer and install a DAW/sequencer on your computer.
>>2976826>record multiple audio signals in syncm-audio makes a wide variety of personal mixersthey can save to a computer using USB or firewireif you want cheaper, they also make multi-input sound cardsdont get something like a 50 dollar mixer, it'll be full of hum and distortion
>>2976837>>2976835Thanks. I'm messing around with speaker/microphone arrays.
How plausible is a pedal as a project to start with?I might get one of those starter kits with parts and start messing around.
>>2976861You can do it. Start here:https://generalguitargadgets.com/https://sound-au.com/index.htmlThen you can work your way to a sampler/looper.
>>2976816I need to try this eventually. Mostly for restoring various things. Though I don't know if I'd trust Ali strips not to be plated steel.I've always wondered how citric acid would work. It's super easy to buy pounds of it but I can't really find much info besides a few research papers.
>>2976256Modifying the wiring of an electric guitar is cheaper than buying redundant guitars, and maintaining them, and lugging them around.Building effects pedals from components or at least kits is cheaper than buying the brand name stuff.That was the main reason for me as a student, anyway. Now I just do it for fun.Other uses are repairing broken stuff (hifi kit, vehicles), being able to properly set up stage gear and being able to fix electrical issues in the house without having to pay a technician 80 bucks an hour.
>>2976861Pedals with digital components (basically anything that involves time-based effects, like echo, reverb, chorus/flanger, loopers) can be a bit annoying but fuzzes, overdrives, treble boosters and the like are a very good place to start.
>>2976861you can make them in tuna/tea cans, as long as they are made out of something conductive and ferromagnetic it'll work against 60/50 Hz induced noise.
>>2976875My old analog electronics teacher got into EE because he was a musician and wanted to fix his stuff back in 1766. He loves loud music so he is almost deaf.
>>2976878>1766Based wig-wearing lute shredder
>>2976879dude probably has 300 years no kidding. Came from a math literate musician to PhD in EE. Pretty cool.
Can I just rely on the autorouter in Kicad and send it to print
>>2976883if it passes DRC and isn't some fancy RF thing or power electronics then probably
pic rel is the ROSA (receiver optical sub-assembly) from a fiber optic SFP module. the little die on the left is a photodiode, and the big die is a MATA-37644B (https://www.macom.com/products/product-detail/MATA-37644).can anyone tell where in pic rel the TIA is? im hoping some of the pads go straight to the TIA's output so i can rebond the die (im only interested in the TIA).
>>2976826If you want a live connection, the cheapest option may just be to have a bunch of USB audio codec ICs on a board with a USB hub IC. 41kS/s x 10ch x 24b = 9.8Mb/s, well within the limits for USB 2.I’d also run a USB isolator, just so you don’t blow up your PC with phantom power or whatever.>>2976837Oh those are pretty cheap.>>2976874Citric acid is a complexing agent (like thiourea), so would likely have some impact on the chemistry. I wouldn’t know what, but it’s probably fine. I should definitely buy some in bulk, if just for rust removal.>>2976899Can you put it in a chip carrier with plenty of extra leads and just connect all of the unbonded pads? If not you could disconnect the bond-wires to the leads that you’re not using. I’d assume it to be one of the 4 pads next to the photodiode if it’s anywhere, but I’m pretty pre-novice when it comes to silicon layout, maybe it’s on some of the other pads. There’s always trial and error.
>>2976881I had a high freq engineering prof who looked like he came straight from the 60s. Floral shirts, bell bottomed trousers, moustache. He played guitar and was the chillest dude ever.
>>2976901>Can you put it in a chip carrier with plenty of extra leads and just connect all of the unbonded pads?uhh not right now, its mounted on a board and if i removed it i would need to figure out how to drive it properly. probably not too difficult, but i would also need to figure out how exactly to remove it from the board without destroying it.i do have access to a probe station, however, so i could just probe the pads in situo. that'll probably be the next step.
>>2976816I added some thiourea to the plating solution and it went from shiny to dark matte. I fucked up. Also my distance from anode to cathode is really small in this shallow dish so it's plating very unevenly. There's some blemishes on the copper too, shoulda washed it with HCl instead of just scrubbing it. Hopefully I can keep plating until there's enough metal to polish.
>>2975961Hello /ohm/. I want to convert a fixed-speed power tool with a universal motor (currently single phase mains powered) to run from a DC speed controller. To my understanding, this would involve connecting mains to both a bridge rectifier and a smoothing capacitor (in parallel) with both connected to the speed controller, with that connected to the tool. Sound right?
>>2975961How to calculate the rest of the components after the bridge?I want an output of 5 V, I have calculated the value for C1, but the values of C3 and R? I get the zenner must be @5.1V and the C2 can be omitted.This thingy must be able to handle the mains directly so from previous posts the first cap does almost all the work, so the 23uF @ what voltage(at least)? since I have problems locating this size and above 50V.Thanks in advance.
>>2976956You’d need a custom speed controller that’s capable of switching hundreds of volts. A smoothing capacitor is optional, there’s nothing wrong with feeding the motor the fluctuating voltage directly out of a bridge rectifier, so long as your PWM frequency is significantly faster or slower than twice mains frequency. With a filter cap, you’ll have a DC voltage higher than the RMS voltage, so the maximum speed will be higher, this potential overvoltage may risk reducing the lifespan of the motor, but it’s probably fine.But why not just use a conventional phase-fired AC speed controller? Seems like a lot of effort for no gain.>>2976963Calculate the maximum possible AC current draw, it will basically be equal to the supply voltage divided by the capacitive reactance of C1. Then use the peak current of that (rms value multiplied by 1.414) to figure out the voltage drop across R, add 5.1V, and get the maximum voltage that might be seen across C3. At least in steady-state, when you switch on the power you could be at the top of a mains peak, in which case a very high current spike could go straight through C1 and fry your circuitry. So you definitely want a series current limiting resistor with C1 to limit this inrush current, then you can do the same calculation as above but with that series resistance instead. A capacitor across the zener diode is a good idea too.Sure you don’t want to use a monocrystalline calculator-style solar panel instead? Or RF energy harvesting with a rectenna?
>>2976971>use a monocrystalline calculator-stylehow?
>>2976971>A smoothing capacitor is optional, there’s nothing wrong with feeding the motor the fluctuating voltage directly out of a bridge rectifierThe idea there is to feed the speed controller a steady voltage. If that's not a concern, it's not a concern.>But why not just use a conventional phase-fired AC speed controller?My understanding is that this affects torque more strongly than the PWM of a DC speed controller. The target is ~40% speed reduction with minimal torque loss. This specific thing is something I saw here:https://youtu.be/gMVIdDKgG5A?t=1118But rather than slow down a wood saw for steel, I want to slow down a steel saw for stainless. It's a bigger, slower, torquier motor with a smaller speed reduction, so the power reduction should be less than in the video. Think it would be small enough for an AC controller to be viable? At any rate, this is for evaluating the viability of the endeavor. I'm currently using a smaller blade to get the proper cutting speed when I want to use the saw on stainless, but that reduces the cutting capacity by nearly half, so it's not ideal.
>>2976976>If that's not a concern, it's not a concernit's almost certainly a concernPWM circuits generally dont like being switched on/off 120 times a secondyour PWM strategy is gonna be expensive, which is why an alternate solution like belts or gears or AC speed controllers are preferredex. a 10,000uF cap at 200V costs like USD 7020A 200V rectifier bridge is 15 USDplenty of inexpensive PWM controllers exist but but only go to 48 or 60Van industrial quality one, 180Vdc @ 10A from Grainer is 900 canadian pesos
probably not the right place to ask but I just swapped my pc into a new case (4000D frame) and the front panel audio is completely fucked. I already swapped the front panel module (rma) and it's the same. shit worked fine in my old case. There is a loud buzzing sound and the audio quality is terrible, sounds like interference. Did I fuck up my motherboard or is there a missing ground somewhere? Rear panel audio is not affected.
>>2976992>front panel audio is completely fuckedso what?only peasants use wired audio in <current year>
>>2976990>your PWM strategy is gonna be expensiveIt's for modifying a $500 saw to replicate the function of a $3000 saw. With the small blade it already cuts stainless tube faster and cleaner than a Fischer saw.>@ 10AThe saw can trip a 20A breaker if asked to. I'd prefer something bigger. If the outlined setup seems reasonable, I'll keep an eye out for a used one like the guy in the video did.>or AC speed controllersWould that indeed be viable in this situation?
>>2976973Well you buy some little solar panels from alibay, and solder them up to your circuit, if its power draw isn't very high. If the voltage range is within your tolerances you might be fine, maybe just a clamping zener to prevent overvoltage. What is it powering?>>2976976>The idea there is to feed the speed controller a steady voltage. If that's not a concern, it's not a concern.If the motor has enough inertia to smooth out 8-10ms-long ripple, it's not a concern. They run smoothly on AC in the first place, after all, their commutation method is basically acting like a full-wave rectifier with no filtration in the first place.>Think it would be small enough for an AC controller to be viableWhat do you mean by that? An AC speed controller can be capable of plenty of power, definitely cheaper per watt than a high voltage DC speed controller, though you could probably make either yourself for something in the ballpark of $20. An AC phase-fired unit may have a bit less torque than the fully filtered rectified system, because the peak voltage will be lower. But as the other anon alludes to, that means a massive quantity of filter capacitance. A capacitor is defined by:>I = C*dV/dtwhich you can rearrange to be:>C = I/(dV*2*f)Where dV is the allowable peak-to-peak ripple voltage. If dV = 10V, f = 60Hz, and I = 10A, that's 8333uF of capacitance, at 180V or higher. Also your power factor may be bad enough to risk tripping breakers, and the inrush current when turned on will necessitate an additional soft-start circuit.Just buy or make a TRIAC-based controller and see if it's sufficient.>>2976992Check if your PSU has a negative 12V rail, sometimes these are required for front-panel audio and not all ATX PSUs have that rail anymore. But mine sounds like shit too and I'm pretty sure my PSU has such a rail. Anyhow, you should buy (or make) a proper USB sound-card, built-in DACs are seldom any good.
Is dc choke for dc bus a must have for vfd drive?
>>2977004>Would that indeed be viable in this situation?dunno, but they're cheap enough to try outso, for the price of a macdonald's gourmet dinner for two, you can find outjust avoid the ones where the specs are in chinglishand, of course, amazon typically lets you return items within 30 days
>>2975961i need to generate anywhere from 0 to 16 PWM signals at a fixed 50% duty cycle at a fixed frequency that might range anywhere from 200 KHz to 2 MHz. for 2 or more active PWM signals, i want them phase shifted to be spaced out equally.>2 channels = 180 degree shift>6 channels = 60 degree shift>13 channels = 27.7 degree shift>etc.the accuracy/precision of this isn't critically important. are there any ICs that can do this, or should i just commit to buying a cheap FPGA and learning how to program FPGAs?>what is this for?an external clock signal on a multi-phase buck converter.
Is it true I can but a bipolar capacitor between my amp and speaker and it will work as a high pass filter?
>>2977045>work as a high pass filter?caps are like resistors whose resistance varies with frequency according to some formula that only nerds knowthese dorks claim that resistance drops as frequency increasesif true it would mean they block lower frequencies and pass higher frequencies, so yes
headphones are electronics right?i have the weirdest issue with my headphones where one side of it will work perfectly and then after like 20 minutes the volume will rapidly fizzle out and not produce any sound.if i unplug them for like an hour and plug them back in they'll work perfectly again until it randomly goes out again. what could be the issue here? i figure the damn thing would just either stop working completely or work, but i can't figure out why it would just suddenly go quiet and then come back if i unplug it.
>>2977049>then come back if i unplug itmost likely cause is oxidized connectorsfor the plug, rub it hard with an eraserfor the jack, spray some contact cleaner inside, plug and unplug the jack multiple times, then wait 10 mins for the chemicals to evaporate before you turn the device back onif you prefer to do it the wrong way instead, lots of people will suggest this: https://www.youtube.com/shorts/TBaH9-kLrOw
>>2977045it will block DC, so technically yes :)
What is the point of OPAMPS in ADCs like this? I can't access the output to make a filter or amplifier, they'd only act as comparators right?
>>2977051definitely not it, the connectors are mirror clean.oxidized connectors would mean i could jiggle the cable and get my signal back, it just lowers in volume over like 3 seconds before it goes quiet and no amount of connector jiggling gets it back.i just have to let it rest or something for a bit before i get sound back, this shit is genuinely baffling to me.
>>2977081I've just realized the chip in question has good DACs, so it can close the feedback loop, just not in the way I've thought.
I'm a noob and just experienced AC audio vs DC for the first time. I have a breadboarded teensy feeding into a dac and it sounded great through headphones but would make no sound through my audio interface. It was driving me crazy, but then I added a 10uF capacitor form the op amp output and it feeds signal through the interface now. Wow I feel stupid but what an interesting thing in life. How can I determine the best capacitor value for this?
>>2977102I think you need to assume the downstream circuits will act as a high-pass filter with the cap.So just do the old Fc = 1/2PIRC but solve for C with Fc being the lowest you want to pass, and R being the input impedance of the thing you are connecting to.
>>2977021A pair of 8-output Si5351 chips might do the trick (probably the C). It can do pretty finely divided phase offsets and can definitely handle your desired frequency range. I’m just not sure if it can do all of those phase offsets on all pins at once, and be robust enough that changing its frequency won’t have to cause all the phases to get jumbled. In any case they’re cheap and ubiquitous enough to buy one and mess about with it.If the Si5351 doesn’t work then you can almost certainly find other DDS ICs that will.>>2977045Yes. The frequency response will depend on the impedance of the speaker. Too small a capacitor and you won’t hear anything but the tinniest sibilance. Too bug and you’ll hear all the bass anyway. Make sure the voltage rating is higher enough too.Consider looking up how to calculate an RC filter’s corner frequency, and how to design a speaker crossover.>>2977049Sounds like a thermal issue, that the minute heating of it running causes something to expand and get loose. You can test this by listening to them on a much quieter volume, or a much louder volume (some distance from head). I suspect the solder joints on the speaker driver itself need reflowing.>>2977081But you can access the outputs. The output of OA1 is on RB1, the output of OA2 is on RA0, and OA3’s output is on RC0.
>>2977109>The output of OA1 is on RB1, the output of OA2 is on RA0, and OA3’s output is on RC0.Missed that. Thanks bro.
>right: designing PCBs, doing analog and digital electronics>left: interfacing with the computerUSB is a pain in the ass.>bullshit on the mcu side>need to write drivers on the computer side
>>2977124If you're not using a USB ASIC, you're doing something wrong. USB UART is fine 99% of the time, though RS232 is cooler.
>>2977124>right: designing PCBs>left: ordering parts
>>2977008>They run smoothly on AC in the first place, after all,Right, but DC speed controllers do not, which is what I was concerned about, as the anon above mentioned >>2976990>it's almost certainly a concern>PWM circuits generally dont like being switched on/off 120 times a secondI imagine that this is specific to individual models, but if you know any general trends for DC speed controllers I would be interested in knowing.>What do you mean by that?Reducing operational voltage does Very Bad things to the performance of a universal motor, much worse than PWM throttling, as demonstrated in the video I linked above. Standard AC speed controllers work by reducing voltage. A phase-fired speed controller would presumably be better, but I'm not familiar enough with them to evaluate what a 40% speed reduction would mean for torque.>Also your power factor may be bad enough to risk tripping breakersThe saw has a dedicated 30A circuit, but I'll keep that in mind.
>>2977124i love this lil nigga like you wouldnt believe>>2977136just get an ASIC to fuck your wife too why dont you
what's the most expensive IC anons ITT have ordered? I'm building a thing based around picrel and the BOM is around $500/piece
>>2977136I'm trying to make heads and tails out of PICs with USB capability and how the fuck do I write a USB driver for linux. Initially I just want to send a analog audio signal (it's ultrasound) to the pc to process it.
>>2977158>but DC speed controllers do notPretty easy to fix, if it even needs fixing. Any high voltage speed controller will have a low voltage supply for its MOSFET and wave generation, likely a switching DC-to-DC converter. If this low voltage DC rail remains comparatively ripple-free, the actual switching of a bumpy waveform won't be an issue. This might be as simple as adding an extra diode and capacitor between the power input this DC-to-DC converter, or as complicated as using an external AC-to-DC brick. It might already be sufficiently buffered, be it before or after this DC-to-DC converter, that it will work fine with extremely high input ripple. Not that I've ever seen such a unit, but my point is that it's easier and cheaper than adding a fuckton of filter capacitance.>Standard AC speed controllers work by reducing voltage. A phase-fired speed controller would presumably be betterStandard AC speed controllers are phase-fired these days. Maybe you'll occasionally see a massive variac being used, but they're expensive. With phase-fired, anything between 100% and 50% will still have the same peak voltage. It's below this that you start to drop off. If this drop in torque is a big problem, you could try to use feedback to measure torque or current and alter the phase trigger point to keep it high, or to use feedback to measure speed or back-emf and alter the phase-trigger point to keep it below a limit. That second option, using a hall-sensor to measure speed, plus some op-amps and shit, seems doable, but electronically varing the phase trigger point is a bit of a pain in the ass without going digital. DC PWM may be easier.>>2977168>Initially I just want to send a analog audio signal (it's ultrasound) to the pc to process it.Anything stopping you from using the existing USB audio standard? It can take 192kSps at least, I wouldn't be surprised if it went higher. You could even ditch your MCU entirely and just use a capable USB audio codec ASIC.
>>2977168I'm kind of talking out of my ass since I've never done it, but don't write a driver proper, use libusb
>>2977174>You could even ditch your MCU entirely and just use a capable USB audio codec ASIC.I have old pics in my bin, I don't have an ASIC>Anything stopping you from using the existing USB audio standard?being retarded and not knowing how USB works>192kSpsthat is more than enoughMy other plan was to write it to a sd card via spi, but that comes with its own problems.>>2977177thanks
>>2977225Also the device side is a problem for me. I just wish computers weren't so evil. I understand why pease threw one off a building.
>>2977225> I have old pics in my bin, I don't have an ASICBut do you have ADCs with the right bit-depth and sample-rate lying about too? Or will you be using the MCU’s integrated ADC? I’ve found some tutorials, namely Microchip’s AN2582 and on a site called “learnelectronicsindia.com”, but both assume you’re using an I2S ADC / DAC. Still, might be a good start, if you have DMA you should be able to just change the audio channel, assuming the usb audio library is capable of that kind of change.And worst case you can just use USB-UART.
>>2977174Thanks, I'll look into it.
I commence the wiring up of one of the two end-plates. It’s pretty tedious actually.
>>2977394
Anyone knows something about how to mount those little piezo bender cells for sound/vibration emission? I imagine that for sound capture they must be glued somewhat rigidly to a surface, but I have no idea about sound creation.
>>2977418>I have no idea about sound creationonly the most underprivileged Biafran children have never had the opportunity to take apart a piezo buzzer using nail clippersto them i recommend google image search for ''piezo buzzer disassembly''
>>2977478I mean from a design standpoint you rude cunt
some anons were helping me out with this design and it arrived today, amazingly the turnaround from JLCPCB was 11 days, and that's with selecting the slow economy shipping option. I think it shipped just before the holiday closures. I even remembered to put the designators on the silkscreen layer this time lel
>>2977513>he didn't painstakingly go through every instance of silkscreen overlap brought up by the DRC>he didn't rotate every silkscreen designator to be the same orientation>he didn't put an anime girl in the copper and mask layersngmi
>>2977513>>2977513beautiful, I love that you put components values on. Very retro vibe.What does your board do?
>>2977519>Very retro vibe.I didn't realise that was a retro thing to do lol, but this is also only the second board I've designed. And it's probably far too complex for a second project, its an all-in-one synth voice, so an oscillator, filter, several voltage controlled amplifiers, all controlled by a DAC chip. It's supposed to plug in to a backplane connecting it to a Pi Pico.>>2977514at some point I got tired of all the objections the Democratic Republic of Congo was raising about my board and decided to just send it
Just finished my desktop audio mixer, I posted the enclosure and finished look on /3dpg/: >>2977535Pic related is the schizobabble schematic. It's made of a few basic components:>5V USB-powered Mazilli ZVS switcher to create isolated +/-12V rails, with some 74HC14 logic to prevent it faulting out>33V zener diodes on my ZVS primary and secondary side, 5.5V TVS diodes on the 5V and microphone lines, a UV LED on the microphone line to clip it to 3V without being noisy like a zener, and a 1.6A input fuse and 1.5A thermal circuit breaker>LM833 summing amplifier with gain of 70 to add up stereo audio from computer, phone, and radio, with direct line-out from this>silicon diode clipping stage running off "line-level" summed signal to prevent eardrums getting blasted>resistors and volume potentiometer to attenuate the signal by ~1/70 again, adjustable from ~1/35 to 0, followed by TL072 output buffer amplifier for driving headphones>internal PCB from a TRRS earphone pair with mic removed and buttons replaced with wires going to buttons on front-plate>microphone passthrough sockets connected to each other, but also connected to a buffering TL072 with passive RLC filter feeding phone TRRS mic line>BJT circuit to detect phone's bias voltage on TRRS mic line and change colour of front-panel LEDAnd soldered onto phenolic strip-board.FYI the whole summing amplifier audio chain is DC-coupled, which is probably stupid, but if it's a problem I can add caps.
>bought 1000 good quality resistors>the higher quality means the leads are thicker, they don't bend at the same angle as the cheap chink shit ones I've been using, and they don't fit in my resistor footprint any more
>>2977674Yeah 7.62mm resistor spacing is pretty marginal on the thicker resistor leads. You can always squeeze them or put them up on angles if you’re desperate.
>>2977680this time round I suppose I can use the ridiculously tiny 100k resistors I once bought by mistake. I guess in the future I have the option of increasing to a 10.16 mm footprint, which seems rather large, or pick some wacky intermediate size that isn't a multiple of 2.54, neither option seems ideal
>>2977674>they don't fit ... footprintgive your resistors dignity by letting them get up, stand up, stand up for they rightsnot only keeps 'em cool, but gives you hundreds of free test points for your scope probe
>>2977690it looks just awful though, it's like using "illegal building techniques" with Lego
>>2977513finished but will probably need to wait until tomorrow to test, everything takes so longany updates from the anon making the two pole LM13700 filter?
actually rather than just blogpost I may as well ask a question: would there have been a better way to decode my address lines? I have a 74HC138 3-to-8 decoder here so that the board can be selected with the right combination of 3 address bits. So I have 8 optional jumpers, one for each possible address. I feel as if there should be some way to set the board address simply by soldering or not soldering 3 jumpers in the right combination, but I think that would also require so many logic gates that using the 3-to-8 actually ends up simpler. Did I miss some obvious method?
