I actually ordered this one since the one that Rob linked to had nearly 20% unfavorable reviews on Amazon, with a common thread of spotty quality control (units DOA or dying within weeks). I actually have one of the ones I ordered that my wife bought in California that I installed on a stairwell last week, but was so focused on the idea of a door-activated switch that it never occurred to me that the logical solution was already at hand. The one I have and installed seems to be pretty well made, and it does work well. I haven't had it installed long enough to get an idea of battery life, but I'm hoping for several months at least in the charging closet, where the door might be opened only two or three times a week. If it becomes a problem I'll get some rechargeable batteries for it.

tanstaafl.