Goal: Add a motion sensor that lights up the clock at night when it detects movement, and make the backlight brightness manually adjustable.

Why: I only have a few requirements for a good bed-side clock. It needs to be easily visible, but not light up the whole room. I am nearsighted, so I’ve always wanted a projection clock so I could see the time on my wall/ceiling in big digits. But the "visible" and "not a bright nightlight" requirements are somewhat in conflict, right? What if the clock was dark until you waved your hand above you, and then suddenly the projection appears! Perfect solution, for me at least. Why no one sells this, I simply don’t understand. So, we’ll have to make one.

How: This instructable is not complete yet! It will evolve in (at least) two parts. This first part is a proof-of-concept disassembly/reassembly, to get an idea what the innards look like and make sure it would be feasible to add features into the clock. I’m not someone who is adept at microcontrollers and electronics, however, so I will be partnering with a friend to do all the modifications. My goal will then be to add more information to this instructable and "complete" it for posterity and others who think this is a neat idea to try.

The subject: The RCA RP5440 was chosen for its features, form factor, and affordable price. The time on the front panel is nice and large, and unlike most projector clocks this one doesn’t look like part of a spacecraft. The projector is aimable, and the case is a good hefty size, which I hoped would mean ease of disassembly and some room for new brains inside. It also has oodles of other features that I don’t need or care about, but hey, free features.

By: ferrix

More: continued here