Reddit:Electronics

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This is my project: ZVS feeding a transformer feeding a symmetrical Cockroft-Walton voltage multiplier. The circuit in the pic is the second part, earlier i posted the CW diagram that i designed with falstad.

I study electrical engineering, and i decided to challenge myself with building this setup. The voltage between the 2 multipliers will be 240kV and produce ~30cm arcs(30cm according to gemini).

I had problems with this ZVS and LTSpice, the simulation was harder to get going than the actual circuit, but today i succeeded with it. I think i'll reward myself with some ice cream later! :)

I’ve been working on a custom CH32V006 dev board for OpenServoCore, which is my attempt to turn cheap servos like the MG90S into smart actuators with Dynamixel-style single-wire UART. PCBWay kindly sponsored the fabrication and assembly for this first spin.

When the boards arrived, I plugged one in over USB-C and immediately noticed the 3.3V rail LED was off. Measuring the rail gave me 0.84V. I checked all 5 boards and got the same result every time, so it was pretty clear this was not a one-off assembly issue. I even injected an external 3.3V supply directly onto the rail and it was still stuck at 0.84V. At that point the evidence was clearly pointing to my design, not the fab.

After staring at the KiCad files and schematics for way too long and finding nothing, I started probing around different test points. At some point I hooked 3.3V up to what was labeled as the +3V3 test point for some reason.

Then I heard a pop, saw magic smoke, and immediately assumed I had just made things worse.

Then I looked down and the green 3.3V LED was on. What???

Measured the rail again: 3.3V.

Turns out the silkscreen test point labels were wrong. That “3V3” test point was actually the EN pin between the MCU and motor driver. So by feeding 3.3V into it, I fried either the DRV or the MCU, and whatever burned open stopped dragging the rail down. In other words, I accidentally failed my way into a debugging success.

From there I started removing parts on a fresh board one at a time. I removed the DRV, still 0.84V. Then I removed MCU, and the LED came back. After another round of staring at the schematic, I finally found the real root cause: I had accidentally swapped VDD and VCC on the MCU. It was staring at my face the entire time. Talk about shame...

I ended up attempted three board surgeries and the third attempt finally worked with trace cuts and magnet wire, and somehow the CH32V006 survived reverse voltage on its power pins and still ran firmware afterwards. This little MCU is tough!

It's not a failure if I never give up, right?

I wrote up the full debugging story with photos and repair details here if anyone wants the whole mess.

The photos are:

1. The finished product! An AT28C256 EEPROM reader/burner on a single-sided PCB
2. A 0.1" dot grid drilling template taped on
3. After drilling and cleaning the surface with sand paper and IPA
4. Traces hand-drawn with an oil-based paint marker (I need one with a finer point...)
5. Etching in cupric chloride
6. After etching and scraping the paint away from solder points
7. Finished soldering
8. A cool view of the traces through the board

Over all I'm very happy with how it turned out. The main thing I'm unsure of at the moment is whether I should leave the paint on the traces or not. I figured it would provide some protection against corrosion, but as you can tell it's pretty fragile and has already been scraped off in several places. I might still just clean it all off.

Hi everyone!

I just finished my new workbench! I extended my existing one(the one facing the desk behind) with the edge-piece facing the wall. Also I sanded the desk surfaces and gave them a new finish. And last but not least, I added the shelf above for all devices.

As you can see it is not completely finished, I am still working on the LED strip that goes below the shelf and some other refinements. But so far I am very pleased with the results!

Rate my setup. I know that the cable management is shit, but I have only one plug.

I discovered that adding a single 1N4004 diode to a Schmitt trigger RC oscillator increases edge jitter by 15x, turning a simple 4-component circuit into a cryptographic-quality hardware RNG for microcontrollers.

I've done (What I think is) a pretty comprehensive write up of the project here:

https://siliconjunction.top/2025/12/04/practical-hardware-entropy-for-arduino-projects/

10eur keyboard from aliexpress, they really wanted to keep the pcb one layer

Someone's gonna start a fire building one of these.

it will be used to control 5 motors from a raspberry pi as well as sense a voltage drop across the resistor for current sensing and motor stall detection using an arduino nano as an ADC. It will be used to actuate fingers in a prosthetic hand for a uni project! less

I dont have more images., I used a raspberry pi pico with a voltage conversion board. the chips were taken from the disk not in a beautifull condition so I need to make these copper boards.. (actually if the chips are taken correctly there are special sockets for them). After the software was done I discovered these chips also were failing ran very hot. So it wasn't a success...

I made this atrocity with a CAN bus module, SD card module, humidity, temp, pressure, acceleration and gyro sensors. The use-case here really to extract and log everything from a CAN bus, dump it to SD and then download the data with bluetooth to an android device and push to a hosted API for analysis. Then optimize how to run an outboard engine (rpm, energy/distance, trim etc).

But my point is, why didn't I do this shit 10 years ago? Or is it just that this has never been this easy before? It's just so much fun. Ignore the arduino in the background, it was my only available breadboard at the time.

I'm a CS major, never really done any electronics but tons of programming on all levels. I can't understand why I have never even tried this before. The possibilities are endless!

Using an ESP32-S3 Devkit for this project, which seems very capable and speaks CAN natively. Feel free to citique the soldering, it's my first time soldering small things.