Just before I headed upstairs, I decided to make an opening for the magnet. This will serve a couple of purposes. Not only will it hold the lid closed, but it will also manage the reed switch, which is responsible for turning the electronics on and off when the door opens or closes.
I started by drilling a hole in the recess, then finished expanding the hole with my dremel tool. The magnet sits just below the surface. In this picture, it's not yet glued in. The magnet was slightly too big for the opening. Rather than expand the opening further, and running the risk of ruining the walls of the recess, I took the magnet over to my sander and knocked it down a little. God bless Ryobi tools!!!