USB DMX adapters and permissions

A USB DMX adapter shows up as /dev/ttyUSB0 or /dev/ttyACM0, and on most
distributions only root and the dialout group may open it. Two ways to fix
that, and the second one is better because it survives a reboot into a
different adapter:

  1. Add yourself to the dialout group, then log out and back in:
        sudo usermod -aG dialout "$USER"

  2. Install the rule next to this file, which makes the adapters ShowVizz
     knows about readable and writable by any logged in user:
        sudo cp z65-dmxusb.rules /etc/udev/rules.d/
        sudo udevadm control --reload-rules && sudo udevadm trigger

Then unplug the adapter and plug it back in, and check with:
        ./showvizz-dmxprobe --list
