Reddit:Electronics

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.

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.

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.

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 -> 3RC 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. Squarewave circuit (input is 3.3v square pwm)
4. Sinewave schematic

For way more info:
GitHub repo

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

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 😁

Hey everyone,

I’ve been working on BugBuster, an open-source/open-hardware debug and programming instrument designed to replace a pile of bench equipment with a single USB-C connection. The goal: give you a device that can program, debug, and manage power and peripherals remotely, so multiple users can share access to physical hardware over the network.

Repo: https://github.com/lollokara/bugbuster

What it is

At its core it’s a software-configurable I/O tool built around the Analog Devices AD74416H and an ESP32-S3. All 12 smart I/O pins are dynamically programmable — you assign their function in software at runtime.

I/O specs:

∙ Logic I/O: 1.8 V to 5 V compatible

∙ Analog input: -12 V to +12 V, 24-bit ADC

∙ Analog output: 0-12 V or 0-25 mA (source and sink)

∙ 4 channels can be connected to the high-voltage ADC/DAC simultaneously

∙ The ESP32-S3 exposes a second USB CDC port map a serial bridge to any of the 12 I/O pins directly from the desktop app

Measurement modes per channel: voltage input/output, current input/output (4-20 mA loop), RTD (2/3/4-wire), digital I/O, waveform generation (sine, square, triangle, sawtooth to 100 Hz), real-time scope streaming

32-switch MUX matrix (4× ADGS2414D) lets you route signals flexibly between channels.

All onboard supplies are fully programmable:

∙ USB-C PD negotiation via HUSB238 (5-20 V input, up to 20 V @ 3 A = 60 W)

∙ Two adjustable voltage domains (3-15 V each, DS4424 IDAC on LTM8063 feedback)

∙ One programmable logic voltage domain

∙ Each output port is e-fuse protected (TPS1641x) current limits and enables set in software

∙ All calibrated with NVS-persisted curves

This means you can power your DUT, set its logic level, and adjust supply voltages all programmatically, all remotely.

OpenOCD HAT (coming)

An expansion HAT based on the RP2040 and Renesas HVPAK will add:

∙ OpenOCD - JTAG/SWD programming and debugging of targets

∙ Additional high-voltage functions from the HVPAK

∙ More I/O expansion

I’m ordering PCBs next week.

All is open hardware and software on the latter the structure is:

∙ Firmware: ESP-IDF + PlatformIO, FreeRTOS dualo-core (ADC polling, DAC, fault monitor, waveform gen, WiFi all concurrent)

∙ Desktop app: Tauri v2 backend (Rust) + Leptos 0.7 frontend (WASM), 17 tabs covering every hardware function

∙ Protocol: Custom binary BBP over USB CDC - COBS framing, CRC-16, < 1 ms round-trip

∙ Hardware: Altium Designer, schematics and layout in the repo

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🤷

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.

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!

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.

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.

Found this place after my regular closed.

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!

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