Inspired by raphnet’s projection clock, imakeprojects decided to build their own version. The clock only turns on when a source of IR light is pointed directly at it (i.e. television remote). This would be good for a room that you would normally like as dark as possible, like a home theater. The clock uses a 38kHz IR detector to trigger a Luxeon LED. You need to rotate the polarizing filter on the clock so that an inverse image will show up on the wall. imakeprojects was able to get a clear image without a lens while projecting up to 6 feet.
[thanks trebuchet03]
