Raspberry Pi Laser Graffiti System

Projecting onto the oft-hacked Green Building from my dorm window

One summer(?) during undergrad a friend and I decided to build a laser projector. He got a laser galvo and set up the control electronics for it. I wrote some code for a Raspberry Pi to stream vector graphics to the hardware over SPI.

A fun aspect of the design was how we got -12V and 12V for driving the galvos. We had no proper power supply so instead we took two regular 12 volt supplies and wired them in series so we could reference the middle as our system's ground. If anything metallic dropped between the power supply cases the system would short out.

Note the water-jet cut steel mounting plate peeking out at the bottom
Galvos