When I originally designed this, I lived on a house boat. I wanted an alarm system that would tell me if I had water in the hull, either because of leaking pipes or a hull breach. I designed and fabbed these little boards, but never did anything with them.
The circuit is set up so that it pulls an open-collector line low when water is detected. If the Dallas DS2405 is present, each board can have a unique ID, and can then be polled to determine which board (assuming there's more than one) is in an alarm state.
The design is clean, and the circuit exhibits very good sensitivity. One day I'll incorporate it as a leak detector to my household alarm system. One day...
- Water Sensor Schematic (13 KB)
- (no image yet)