If you are using a BenQ MW632ST projector and want to control it from a Linux computer (e.g. the AR Sandbox CPU), I have written serial remote control software. The program is “bewield” and may also work with other BenQ models.
I use this to automatically power on and power off the projector as our sandbox computer boots and shuts down. You will need to provide a USB to RS232 serial cable to use this software with your AR Sandbox.
The bewield source code is available with build instructions. bewield is GPLv2+ licensed.