This project is a knob for controlling volume (or anything that a USB keyboard can). It uses a AS5601 sensor as an encoder. It was developed using Bluepill board.
You can download OpenSCAD designed models for 3D printing.
The quickest way is to use just:
git clone https://git.sr.ht/~mronetwo/magknob just setup_toolchain make bash flash.sh src/magknob.bin