TL;DR < You can find the source code here. I used the Wii Nunchuk controller to prototype one handed controller for creating computer graphics. I used the Blue Pill board which carries a STM32F1 microcontroller with a built-in USB peripheral. That allowed me to implement it as a true USB HID (Human Interface Device) for the Windows OS. The results were disappointing. My USB HID implementation was poor. I have fixed several important bugs in another project.
