Many digital cameras are battery-only, and can’t be directly connected to an outlet for an infinite source of power. That’s ordinarily not a problem, but can become an issue if you attempt to do things like time-lapse imagery, for which the camera needs to stay powered and perfectly stationary for extended periods of time. That was the problem faced by Instructables member txoof with his Olympus E520. Handy with electronics and woodworking, he decided to build his own AC/DC interface for the camera, crafting a wooden mold that acts as a wall-powered “battery”.
If you have the same problem and aren’t afraid of sockets and buzz saws, check out his tutorial for instructions on how to do this yourself.