Reddit:Electronics

I got so fed up with the stupid interface on the front of my automatic cat feeders that I decided to make a web interface and use the ESP8266 to control them. They are very simple devices. Across two different brands of feeders I have they use the same internal mechanism, so this should work pretty universally across all generic-looking cat feeders...

I was going to design a custom PCB but the circuit is so simple it was pointless and would've taken weeks to arrive. I cut the original wiring harness and crimped on JST-XH connectors to make it look somewhat professional.

cat feeder from brand #1 wired to my board

cat feeder from brand #2 wired to my board

The prefboard I made (I made 3x of them)

You can check out the code and some more images of the feeders and board (front/back/etc) here:

https://github.com/captmicr0/EspCatFeeder

Hey everyone! I’m excited to share my latest project: a tiny, open-source RP2040-based board with an integrated addressable LED matrix. It’s built on a 4-layer PCB, and the LEDs are ultra-small (just 1mm x 1mm each), using WS2812 for full addressability.

https://preview.redd.it/5whyzmxtta0e1.jpg?width=1800&format=pjpg&auto=webp&s=f3c11d04357dbf23259972b1255bea51caf96379

https://preview.redd.it/4hhhaijuta0e1.jpg?width=1800&format=pjpg&auto=webp&s=dd44466247e926234ba572ed3b7222cdddf1bdc9

I started tinkering with transistors because it’s what I am mostly learning this semester. First I tried to control output using the PWM pin from my RPi. After that I got the idea of building an RC car and doing the input to the motor from scratch. My first working test is an H-bridge using 4 npn and 2 pnp transistors with modulation through the Q2 and Q4 npn.

Right now I can generate a rectangular wave. The 2 LEDs are in opposite directions, so a positive voltage turns one and a negative the other. The This week I want to bring it to uni and test the sinusoidal generation and efficiency with the oscilloscope.

Long time lurker. I consider myself reasonably handy but this was the first time working on an appliance. Grabbed this microwave for $50 on Facebook marketplace 6 months ago. Friday it did the whirlpool hum of death. Unsure if it was the diode, capacitor or magnetron I replaced them all. Got all components off Amazon and replacement took 1.5 hours from taking it down to putting it back up. Now I’m on Facebook marketplace looking for “broken” appliances I can fix and flip haha. Thanks for this sub for giving me the confidence to do this!

Just wanted to share my first dc circuit, it is for my first circuits class, as a end of semester project.

It consist in just a relay, a 1000uf capacitor and a 330 ohm resistor.

It still is not the proper or final circuit, as I'm using a 5v relay with 12v as power source. Also it is conected in the "inverse way" as the leds need to imitate signal lights from a car.

Tomorrow I will buy the correct parts but for the moment I'm happy to see that this works and I can do the math to understand it !