We had a competition at work (I work at an engineering company) to build a remotely-triggered projectile launcher (i.e. potato cannon). I used the Glowforge to make a Nigel Tufnel-inspired control panel for my cannon…
The box holds an Arduino controller that took the potentiometer signals and opened and closed relays to mix air and propane in a pre-mix chamber, and then dumped that mixture into the combustion chamber where a neon sign transformer firing through a spark plug set the spud in motion. In manual mode, the four buttons on the right fire the corresponding outputs. Tabbed box layout done on Makercase. A lot of fun to be able to whip up a custom enclosure like this one.