Photo Electric Switch
I'm sure they probably make a low voltage inverter for signal wires but its probably ten times more expensive than a new cell. You could use a relay and wire it to the normally closed contact so when the cell goes off the relay opens the contact.
Sarcasm is my friend
I'm here to learn too, i do mostly commercial/industrial/new construction and this place is a great way to pick up tips on residential from some good electrical minds. Excuse the spelling, my phone has a mind of it's own.
Last edited by andrew79; 07-12-2012 at 04:43 PM.