OK I am not sure if this would be worth it besides the learning part, as how underpowered a RPi is, still a nice writeup and if you have a RPi that can run on its own generated power, maybe something to do?
https://www.hackster.io/iayanpahwa/diy-crypto-miner-using-raspberry-pi-in-under-10-minutes-20cdd2
Pretty fast plotter too.
https://hackaday.com/2022/06/19/this-arduino-pen-plotter-is-built-for-speed/
Nice but complicated build for a magnetic based transmission.
https://hackaday.com/2022/09/02/magnetic-gearbox-can-go-fast-but-not-hard/
I like this build, pretty simple (thought doesn’t have the vanes yet). And a slow spin already cranks out some impressive voltage
This is a need bot that can open and close the curtains for you. Of course you need a decent rod and the curtains need to be those in and over types. The downside is with the discount they are still $75.
I like this build, but a few things I would add is a tape measure on the top of the backstop, a “stop” for repeat cuts, and a sliding bar on the backstop to add stuff to the sled. Of course my current sled is pretty basic, so this is better than what I have now.
https://www.instructables.com/Table-Saw-Sled-With-Miter-Accessory/
The author sells most of the stuff to do this too. Basically you use conductive tape to line out the postive/ground lines, use sticky LED’s to “glue” onto the mask, and add a battery on the inside (coin). And done. Nice build overall.
If I still had a pool, this could be a build for me, helps monitor different aspects of the pool and equipment using an ES32
https://hackaday.com/2022/04/16/iot-pool-monitor-helps-you-keep-it-crystal-clear/
The author took and old plotter and make a motorized camera slide out of it. Nice build, only issue I can see is its a “short” slide.
https://hackaday.com/2022/04/07/turning-old-plotter-parts-into-a-smooth-camera-slider/
Should work with other controllers, basically you have a resistor in a circuit, and if it gets wet, the circuit is shorted out so you detect that. I put 2 wires in a sponge myself (separated) an when the sponge gets wet, it connects the wire (thus wet). This seems a bit nicer build, but could drain the battery faster
https://www.hackster.io/happyheart32/water-level-sensor-diy-9ac7a6
