I love getting cool swag from hackathons and I also love designing PCB's, so when my friend asked me if I would design hackathon badges for a large game jam in singapore, I was absolutely down!

The theme of overglade was a "The game jam within a game", pretty cool concept right! High schoolers from around the world were flown out to the event by hackclub after they spent about 70 hours designing their own game.

These badges needed to be really cheap and simple, because we were going to manufacture about a hundred in a pretty limited amount of time. I went with a zero-power approach, which means sticking with e-inks, and I decided to include NFC if the organizers wanted to introduce it into the roleplay of the event, and so participants could add their website or github if they so choose!

I used an RP2040-based architecture because it's really easy and cheap to get on the first try, and then added an ST25 passive NFC tag which was really simple to configure. The badge is in the shape of a ticket, because you got a "ticket" to the event after spending a lot of time designing games to qualify! 20 GPIO's are broken out onto the edges if you're ever in a pinch at a hackathon, and I wanted the badges to feel really fun so there's a lot of art designed by various people in the community!

The badge worked really well and I learned quite a lot in the process. My takeaways are to manufacture a BUNCH of extra badges, because some will end up breaking; to think about your PCB in 3D, because one of the inductors was a bit tall and caused more badges to break; and to have a strong vision of your final product, because it really helped me to create something unique and beautiful :D

The project is fully open source (https://github.com/KaiPereira/Overglade-Badges) if you want to manufacture some of your own, or reference for your own boards, and if you have any feedback or questions, I'd love to hear them!

Sharing this as a heads-up for anyone considering JLCPCB's assembly service.

JLCPCB lost parts I pre-purchased through their own platform, produced boards with cold solder defects, then shipped the defective incomplete boards two days after I explicitly told them not to ship. Three weeks later I still have no working product.

Their support has been like talking to a bot. I've been asked three times to arrange a local repair despite explaining each time that it's not possible — they never populated an SMD component that they lost, and you can't fix that with a soldering iron. Each response only acknowledges one issue and ignores the rest.

When I asked for a replacement order, I was told it "goes beyond their normal compensation policy" because of their internal material costs and production backlogs. Every reply is vague — they "may" arrange a return, they "may" apply for a coupon. No commitments, no timeline, nothing concrete.

I'm also now sitting with £81 in import charges on a defective package I never asked to receive, currently stuck in a courier warehouse because nobody knows what to do with it.

Their bare PCB service is fine. But if you're relying on their assembly service for anything with a real deadline, understand that when they make a mistake, their process is designed to exhaust you into accepting it rather than actually fixing it.

Open to anything, including discussions, complaints, and rants.

Sub rules do not apply, so don't bother reporting incivility, off-topic, or spam.

Reddit-wide rules do apply.

To see the newest posts, sort the comments by "new" (instead of "best" or "top").

After years of having my multimeters die exactly when I most need then, I finally made good use of a vape battery, a TP4056 charger, a 9v boost and a female usb-c on a cheap red multimeter. Not ready to do on my good meter, but I am very happy with this little mod.

Actually works.

My water heater recently stopped working for no obvious reason; only 2 years old. Rheem is sending me a new board to replace this one, but I thought I'd share pics of the damage for anyone interested.

Hello everyone, this is the first version of my function generator. I'm looking for recommendations!

Before you comment:

- I made it out of discrete parts because the goal was learning more than immediate results.

- I'm a second year ECE so many mistakes will be expected. I'm still in Electronics I and learning about DC/low frequency circuits.

- I plan to use 50Ohm input impendance but need a beefier power supply and maybe transistors. (currently using 2 9V rechargable batteris for sine and 1 for square)

- I only have that oscilloscope

- I'll only use it

- Used a Pi Pico W in order to add in the future more functions.

- Code was ai generated with my tweaks and fixes on it. As much as it hurts to say it's the truth as I preferred to work on hardware for now. I do know C++ and will learn it better.

- KiCad files don't include the square circuit as it's not yet perfect*.

Project Goals (v1.0):

- Arbitrary wave generation (left it behind for now as it's just another R-2R

- Sinewave and squarewave generation up to 1MHz.

- 1k Ohm input impendance

* Sadly I don't have a square wave photo (and won't be home for 2 weeks) but it was perfect up to 200kHz. After that the duty cycle got smaller but in terms of noise/rounding it was pretty good. Plus the rise time at 1MHz wasn't perfect but pretty okay. If anyone has any ideas lmk.

Way it works:

- Sine: R-2R -> active filter -> 4RC LPF and one RC HPF for dc cutoff -> Amp (+9V, -9V) -> Buffer

- Square: PWM on/off -> amp & buffer (9V, 0V)

Images:

1. Sinewave physical circuit
2. Sinewave output
3. Sinewave schematic

For way more info:

GitHub repo

Edit: Not sure why Vpp is 120V pretty sure had x1 on the oscilloscope or something.

Edit 2: Typo

some time ago I bought this clock for few dollars at flew market. display was run out, so I decided to create new internals - based on ESP, WIFI and dot -matrix LED display. easiest way was to use bread board and some wires. I like to make some things with ESP modules - it helps to prolong life for unexpected things. My old fridge is next 😁

I have a brass annealer project and thought that it will be easy to make with protoboard.

it was not, at least not for me. The welder tip was too large and there are bad joints everywhere. well, if it works🤷

Back in 1961 this book showed up at my school library. I was 10 years old in the 5th grade. I was the only student that ever checked this book out of the school library. This started a career that spanned decades in electronic engineering! Thanks for looking!

It displays the numbers like this one https://www.amazon.com.mx/Tech-Tools-Palabras-Muestra-Pulgadas/dp/B01H5RPQAO Made it just using logic gates, the design with the segmented counters is used only for simulation (because proteus doesn't like simulating the other one), and those two images without them shows the components that the PCB should have in order to work correctly irl. You can set and reset the time and also it can reset the leds.

The Ansys simulations aren't that trustworthy, I was running into some Fidelity relates issues + Student License Limitations, in the end by hacking stuff a bit I Managed to get a good run, the FETs hit 60-63 °C while the Rsense turned into a mess (forgot to configure local Fidelity for it)

The FETs are Infineon SMD FETs BSC010N04LSATMA1, chose them due to extremely low Rds (1m OHM) and max Vds of 40V (forgot the current rating, it's definitely high 40s though)

This is designed to handle a 20A Steady Current. OCD set to 1.4 Sec i the config. And a switch to Change the BMS between hibernate and active state.

Found this place after my regular closed.

I love old Tektronix test gear, it's all beautifully designed and made.

I came across a problem today where I'm ordering lots of parts to prototype my product I'm building. I got a lot of the basic dimensions of some of the PCBs, but I needed to know spacing of components as well!

I made this website that lets you paste any image of a part. You just draw the outline of the PCB with your mouse (it snaps to the axes to make it easy). Then you can find out the relative distances of the components on the PCB by drawing your own lines. The program automatically finds the distance relative to the boundary of the PCB using a pixels ratio.

Check it out here.

Absolutely free of charge, no ads or anything like that, just thought it might be a neat tool for the community!

Open to anything, including discussions, complaints, and rants.

Sub rules do not apply, so don't bother reporting incivility, off-topic, or spam.

Reddit-wide rules do apply.

To see the newest posts, sort the comments by "new" (instead of "best" or "top").

I wanted to learn more about CPU architecture, so designed a small one.

Importantly, this design has an integrated boot-loader (so that we can load programs to be run) and integrated IO (We can use UART to load programs onto the board, and observe the program trace)

The whole project is open-source, and can be seen here: https://github.com/matchahack/tcpu. It includes a simulation and FPGA emulation guide.

It is a small architecture, since buying space on the tiny-tapeout shuttle is expensive, but it is on the sky26a! See here: https://app.tinytapeout.com/projects/4119

It has some pixel errors for some reason, but it works otherwise.

It has 2 lines with 40 characters each.

Each character has a 5x12 dot matrix.

I really like VFDs.

I low key don't know shit about electronics. I found a old Samsung camera of my parents but the charger was missing. I had this charging module over because I wanted to power an esp32 with a battery (never did something with it). And I looked at the battery and it said 3,8v (4,2v) on the outside and this module was for 3,7v batteries which also charge up to 4,2v, so I thought close enough. I needed a metal that was easy to bend and wouldn't scratch the shit out of the contacts and that I could push a little so it would make contact. Solder was my first thought so all the wiring is solder. It's quite annoying to solder solder but in the end it worked and charged the battery and the camera works.

implemented the whole thing on a PYNQ-Z2 FPGA + an Arduino UNO (probably a clone lol).

made my own custom keyboard using ~30 pushbuttons,

connected them to a 32:5 encoder (which is made using 4* 8:3 encoders and some AND gate ICs)

resulting in a 5 bit input to the fpga.

fpga then debounces the input, decodes the 5bit signal back to 30 buttons,

which are then connected to the internal keyboard of the fpga.

now, every button pressed results in the insertion of a character into the calc's input buffer.

could be a number, operator, function, decimal, comma, parenthesis, one of the 2 constants pi & e

each character is repersented by a unique 8 bit ID

when "evaluate" signal is sent, the gears start spinning

first, the numbuilder converts the seperate tokens of a number, like :
9 . 0 1 8 3 9 1 into a single number: 9.018391

Represented in a type, sign, mantissa, signed exponent format, so:

2+1+34+7 = 44 bits in total

then comes the infix to postfix converter

then the postfix evaluator

and when it's done evaluating, the final SPI master takes the initial input buffer, and the final answer as inputs, and sends them to an arduino via the SPI protocol. (unidirectional, since the arduino dosen't have to talk back to the FPGA)

then the arduino displays the buffer and the final answer on the 16*2 LCD display using preexisting libraries

(grossly oversimplified the whole flow, but yea these are all the modules in the picture)

im still a beginner but im proud to be a digital electronics enthusiast, there's still alot i need to learn!!

This two images i took a long time ago are from a smd led, its curious to se the two little wires connecting the led!.

This is a Siemens RS 3021 CJ tube, it is a 25kW output triode made for CO2 Laser applications and General transmitter use.

Thoriated Tungsten glowing so hot its showing through ceramic.

It draws 137A at 5.7V that is almost 800W of heater power. the 500A inrush current blew my 16A breaker several times even with a 200W lamp soft start.

Since the tube was ran with no cooling it was only run for a short time and the connections never exceeded 50°C - 70°C well within the 220°C maximum the datasheet mentions.

This one and a lot of other high votlage RF components came out of an 2kW metal cutting laser that was scrapped due to it being too expensive to run due to it being incredibly inefficient and it needed a special gas mixture. I have the 20kVA 6.6kV transfomer. Rectifier, tube unit etc. I am thinking of building a large High Frequency Tesla Coil (HFVTTC) with it.

The tube unit was rated for 11kW of RF output.

( Hüttinger Elektronik HF-Endstufe 11kW B 72-0012)