Fairly recently I discovered the Rust programming language and fell in love with it! So much so that I decided to change the hardware to an STM32 microcontroller and rewrite the entire firmware in Rust. You can take a look at the code over here: https://github.com/SamP20/SelfBalanceSkateboard/tree/master/RustFirmware. The C firmware is still there if you're interested, however it's incomplete compared to the Rust version.

The Skateboard is now fully functional at last! Unfortunately however it's a bit unstable to ride in practice. The flexibility in the threaded rod is partially to blame, however the differential steering doesn't help much either as you have to remember to lean as you move the steering joystick otherwise you'll fall off. If I ever get time to rebuild this project I may opt for a single wheel design similar to the commercial OneWheel as it looks a lot more intuitive to ride.