Electronics Damp sensor

Hi all,

bit a or silly question, and I am sorry it not to do with computing, but how can I make a small water detector, that could fit between the sealing joint of a bathroom waste drain. The reason I ask, is cause the joint is hidden under the floor boards, and so should the seal ever spring a leak, i dont want to wait 4 months to notice it when my ceiling is sagging due to it being soaking.

Thanks guys, and sorry!!!

 

This could be useful, maybe?

 

You could try something like this

http://www.electronic-circuits-diagrams.com/alarmsimages/alarmsckt4.shtml

http://www.mitedu.freeserve.co.uk/Circuits/Alarm/walarm.htm

http://www.aaroncake.net/circuits/raindet.htm

 

This should do it. It normally turns on a bildge pump, but you could have it turn anything on, an alarm for example.

 

A simple float switch?

 

Make a PCB with two unconected tracks in a spiral with a few mm gap between them. If water falls on the board, a weak conection will be made and can be used to trigger a transistor by using the PCB in a standard potential divider arangement with another resistor. You could also just use two wires or bits of metal.