When I was working on my smoke detector changing system I thought of this idea:
At night when the smoke detector wakes us up signaling a low battery condition, we usually think of a ladder or a baseball bat.
My thought was to create an inductive loop charger that you would raise up to the smoke detector, go back to sleep, and awake to recharged batteries.
I believe that my electric toothbrush uses an inductive charger for 3 VDC.
The batteries and the internal charging loop would have to be made small enough to fit inside the smoke detector.
Now, that I am designing an automatic water ON/OFF system using MS16A's I reminded myself about my old idea.
Imagine how nice it could be if we could recharge our motion detectors every 2 months or so, by an inductive charger.
This is my smoke detector invention:
HBO:TV's Top 5! Sep. 9, 2007 - 'Curb Your Enthusiasm'
http://www.youtube.com/watch?v=UkvFx-_pLqoLarry David beats his smoke detector to death with a bat
http://www.youtube.com/watch?v=TP21wqv0ia0