I’m looking for a simple way to detect if water is on a surface, as in a leak needs to be detected. In actuality, it would be inside a dehumidification unit and I’m trying to detect if the drain line has clogged and water is backing up inside the unit. I’m already planning on utilizing a float switch, but I’d also like to look at the possibility of detecting when water is starting to collect.
I believe I’ve seen a couple simple circuits involving merely two conductors separated by a relatively small distance and then bring this into an analog input. The device would detect the change in input level when water allows conduction between the conductors.