Hello,
An interesting project. You have several options (my opinion):
- you leave everything to Ardru's environment and talk to him through communication (RS232, or ..). At Rpi, the possibilities for UI are endless.
- you realize everything on the Ardruino environment, even there you can create a very nice GUI with a touch function.
- you create a program in the Python environment, where it is possible to nicely implement PWM for dimmer control. Communication between python and B4j is also not something scary.