This project implements a USB-HID device, a joystick using a rpi-pico.
git clone https://github.com/ad-chaos/JoyShtick/
cd JoyShtick
make
All the build artefacts will be available in the build/ directory, of interest should be the uf2 file
if you have picotool installed, you can run make flash and load the uf2 file to the board.
An HID gamepad can have (according to the provided descriptor in tinyusb) two joysticks, a hat and a lot of buttons. Now even though the rp2040 has got a 4 channel adc, only 2 are available for GPIO, it would be nice to buy a separate 4 channel adc and use two joysticks, I have the ads115, need to get around to it.