Back in 2001, [Helmar] made an awesome monochrome video display out of a red laser pointer and a spinning 18-sided mirror. Blue and green lasers are much less expensive than they were a decade ago, so [Helmar] decided to go full color with his laser projector. (In German, so fire up Chrome or get the Google translation)
The ancient website for [Helmar]‘s green-only projector goes over the principles of operation. A single laser shines onto a multi-faceted polygonal mirror. This is reflected onto another mirror that provides the reflection for each line in a frame of video. Earlier this year, [Helmar] hacked up a red and blue laser to complement the preexisting green laser. The end result is an RGB projector powered by friggin’ lasers.
As far as we can tell, the projector only has composite input; the attached DVD player provides all the signaling for that. Amazingly, [Helmar] didn’t use a microcontroller for the circuitry. All the electronics are simple logic gates. Really amazing if you ask us.