My wife and I wanted to project movies onto the ceiling so we could watch them from our bed. So I made a mount for a KODAK Luma. It's made for a 33.9mm thick headboard but could be adapted pretty easily for other beds (Fusion360 file included)

Hardware:
* ¼"-20 (tripod screw thread) x ¼" to attach to the projector's tripod mount
* Two small screws for the hinge. It's sized for #4-40 x ½" screws I had lying around but a M3x10 would probably also work as well. You may need to clean out the hole a little bit first (or tap it if you have a set of taps!)