Reddit:Electronics

Here’s a decoder I made in my class! It takes the binary inputs from the four switches and uses a seven-segment display to turn them into decimal numbers. Made with a 7447 CMOS IC.

I know it’s very disorganized and I could certainly get better at saving space. I’m still new to building circuits, but I still think it’s really cool!

Thinking of using it for either an induction heater or a dual resonant solid state tesla coil, but next up will be having to deal with annoying gate drive stuff first.

it's displaying GHIJKL on the display. The display is a Maxwell MAX7219 7 segment display run from an ESP8266 generic. I had to write my own driver so I could show what I wanted via the letter and not binary literal. Am I a look

Came across this capacitor bank inside of this giant battery charger just figured I'd share, LOL. It has (3) 29k microfarad 200vdc, and (1) 13k microfarad 200vdc capacitors. Gives me the heebie-jeebies just looking at it... It has a built-in capacitor discharge button but still...

Wanted to share a picture of our progress on our open access health tracker.

We hand assembled our first prototype (left) in 2025. Around 140 components with the smallest being 01005. Our learning: DON'T use 01005/0204 if you hand assemble. It was not a lot of fun, but we got our first prototype to work.

We redesigned and improved. This time using a 4 layer flexible PCB + stiffener. AND we learned, ordering the prototypes mostly pre-assembled. However, we ran into the problem that we forgot to thermally shield our temperature related sensors (any suggestions on this very much welcome). We also ran into the issue that our 2.4GHz antenna didn't work anymore, most likely due to the PCB change, but a small cable will do the job.

Now we are working on our third prototype. Integrating more sensors, compacting and fixing mistakes we made.

For a long time wanted myself Poe capable switch but didn't wanted to pay like 3x or just subconsciously wanted to die in house fire one day, it's not important. Basic 8 port 100m switch with all pairs available on connector(Wich is unsurprisingly rare). Ptc fuses rated 0.5a with 1A trip point. Power for switch is made from led driver scalvaged from cheap bulb. It is slightly modified to work from polarity agnostic 48v and provides about 4v isolated which is enough to power small switch. It is second attempt, first switch was fried because there 2 annoying standards with + and - inverted requiring a lot of diodes to ensure not frying anything which I skipped thinking working with a known Poe source I am safe and having non isolated step down converter is fine. Wrong assumptions indeed. Now everything works relatively safe, in final version before assembling I added isolator between fuses and transformer legs. No fire yet.

Designd my own PCB and got it from JLCPCB. Nice gift fir valentines. I am using NE555 to make the LEDs flash if you want to see how it works comment I'll post a video.

No idea what this is. Not even sure what it does. Just showing it around.

Hi everyone,

This is my Healthtracker project. This will be my first real 6-Layer PCB I have designed using EasyEDA.

I am using the nrf5340 for this low Power Bluetooth application paired with couple i2c peripherals for activitiy, heartrate, time & temp. So I don't run out of storage, I integrated infineon 8-Mbit FRAM.

Power is supplied to various DC/DC Buck/Boost converters found at the top.
Charging is possible via USB C.

I am planning to programm the SoC using the pinheaders and my DevKit. (pinheaders will be soldered out, after programming and Debugging).

Oh, don't be confused with these many throughhole vias; JLCPCB curently doesn't support blind or buried vias....

Have a great day.

I couldn't for the life of me understand why the multimeter was not reading correctly when using bananas to crocodile cables. Lesson learned: don't cheap out on cables.

PONG has always fascinated me. A video game made entirely from logic blocks from the 74xx series. Without a processor, memory or software.

After seeing an original PONG console at the Berlin Computer Game Museum, I set myself the goal of recreating one. And now it's finished.

I didn't want to use the large arcade cabinet like the original as the ‘housing’, but something smaller that would focus on the circuit board. Because it is the ‘star’ of PONG. Ingeniously designed by Allen Alcorn, who went down in computer gaming history as the designer of PONG. But as I said, it's not a computer.

I redesigned the circuit board from photos and templates. Conductor track by conductor track, component by component. The ICs are still relatively easy to obtain (I also recreated an Apple I, which was more difficult, or rather almost impossible nowadays).

The control panel also had to be the same as the original, and of course a real coin validator had to be included.

This “Mona Lisa” was created as a technical demonstration by a by a Japanese company that provides PCB assembly (PCBA) services.

Instead of using PCB traces or silkscreen artwork, this piece is built from about 10,000 1608-metric SMD components. The image is formed through the color variation of resistors, ceramic capacitors and other components, turning electronic parts into a high-resolution mosaic.

This post presents a component-level schematic overview of an ESP32-S3-based

vision development board.

The shared material focuses strictly on electronic circuit design and

interconnection of active components, including the MCU core, power regulation,

and peripheral interfaces.

Primary active components shown in the schematic:

- ESP32-S3-WROOM system-on-chip

- DVP camera interface connected directly to the MCU

- 6-axis IMU interfaced over I2C

- MEMS microphone connected via I2S

- SPI-based microSD card interface

- Dedicated voltage regulation stages supplying RF, camera, and sensor domains

The circuit design integrates vision, motion sensing, and wireless communication

on a single ESP32-S3 platform. Power integrity, signal routing density, and pin

multiplexing constraints are central factors influencing the schematic structure.

The schematic is provided for component-level reference and electronic circuit

visibility.

Since it's newly created, it doesn't have a GitHub repository yet.

I love maps, transit, and DIY electronics- here is my recent project combining all three!

I had an 8"x10" PCB manufactured with a custom map of Boston silkscreened on the front side. On this map, each station on the Red Line is marked by two LEDs- one for inbound and outbound trains. Data is streamed from the MBTA's API and displayed on the board, showing location, speed, or occupancy information.

This version utilizes WS2812B-2020 LEDs and a very simple two-layer PCB. For future projects, I would be interested in using rear-mounted LEDs (such as SK6812-Es) for a more polished look.

If you're interested in the project, all of the code, PCB files, and tutorials are open source: https://github.com/tomunderwood99/CharlieBoard

S21Pro, successful rework and trace repair. AMA!

( Ps: Sorry about the double post; I wanted to be more detailed than my prior post because this community is more receptive than the soldering subreddit. Also, I am fully self taught on everything here, so pardon my ignorances on some terminology. Not IPC certified either. — — — )

The goal of this repair is to achieve a successful count of all 65x asics on this PCB. Image 2 shows a fail on full count. Image 12 shows a successful fix.

Image 1, shows my main circuit with issues, conformal coating still present. Arrows and circles identifying components I eventually replaced, or repaired. Darker spots on the conformal coating indicates that these circuits overheated and likely shorted out.

Image 2, shows the entire single layered PCB, plus includes the readout from my ASIC tester (it’s called a Stasic.). Started removing conformal coat.

Image 3, closeup of problem circuit with conformal coating removed. Burnt diode from my boost circuit and clear signs of shorts throughout several dependent circuits.

Image 4, propane blowtorch used to reflow the first half of my boost circuit. ( I imagine this photo is what will cause some concern. This is a method I’ve used thousands of times at this point. While it works, it is not my sole methodology for reflow. Also, I offer warranty on my repairs. )

Image 5, closeup of first ASIC removed. My two main vdd signals would not pass this chip. Removal helped identify those corroded pads, and prompted me to remove, and check other asics in the physical area.

Images 6 and 7, closeup of the previously corroded pads on the asic chip; cleaned and ready for tin. Next was the hard part.

Image 8, closeup tinned asic. Passed continuity test, despite the ugly-lumpy pads.

Image 9 and 10, closeup of the original pads where my first corroded asic was removed; and closeup of it after being tinned.

Image 11, previously corroded PCB and ASIC chip repaired, and successfully placed. (( Just throwing it out there that I placed this asic with the blowtorch lol. ))

Images 12, 13, and 14 (12 & 14 unlabeled), closeup of the entire area fixed. Another angle of the chip placed (that bridge is intentional; bypassing a 1k resistor), and the reveal that the entire back-half of this board is solid aluminum.