udev rules
i can never remember how to do this on Ubuntu, so i'm writing it here:
to find out the magic strings to match in a udev rule:
udevadm info -a -n PATH_TO_DEVICE
where PATH_TO_DEVICE is something like /dev/bus/usb/CONTROLLER/DEVICE
make sure to create udev rules *only* using attributes/subsystems/etc listed in the same device in the hierarchy! otherwise it won't match.
when you want to fire the rules again:
sudo udevadm trigger
This tutorial is pure gold when needing to talk to custom HID devices over usb