RadioKnobs is a small project for Arduino that takes input from rotary encoders and outputs serial commands via USB. It's intended to use along with a Raspberry Pi running HiFiBerryOS.
This project was written in VSCode using PlatformIO. After adding the project to PlatformIO, use the pio lib install command to install library dependencies.
The project was built using an Adafruit Metro Mini 328 but should work with a number of other Arduino-based microcontrollers. If you're not using a Metro Mini you should make sure to modify platformio.ini to reflect the environment you're using.
Unless you plan to use 3 rotary encoders with the exact same functions on the exact same pins as I have, you'll probably want to modify this code. The most significant bit of code going on is the pollRotary function, which made it a little simpler for me to add/remove behavior to the rotaries.