For a “sign” to advertise the 7th annual Westport Maker Faire, I made a custom laser projector (it had a stronger green laser for the event, but I’ve since re-installed a safer, lower-power red laser). My original intent was to project it on an outside wall of the library, but that was overriden by safety and weather concerns so I set it up in the Great Hall.
It’s powered by an Arduino, and uses some inexpensive XY mirror galvonometers I purchased from China. I also made the case, and CNC’d the top with my Maslow. At some point, I’d like to rig this up for generic XY input and hook it up to my Asteroids machine.