“I had a hard time getting the trackball working with evdev-mouse.py. The Github page has not been kept up to date and I had to do some digging to get it working. The main issue that stumped me was being told the INT pin isn't needed when in fact it needs to be connected to GPIO 4/pin 7. INT is required to run evdev-mouse.py. From my attempts, the simplified install doesn't work for Bullseye. Bullseye must be manually installed. Follow directions for manual install on the github page, then follow these modified directions for evdev-mouse.py to work on startup.
cd examples
sudo apt install python3-evdev
sudo modprobe uinput
sudo cp 10-trackball.rules /etc/udev/rules.d/
sudo udevadm control --reload-rules”
