Water leak detectors with servos on taps are cheap now. But not any room where water cranes are placed in a home, have power and signal wires for water leak detectors. Here water leak detectors were equipped with Bluetooth LE beacons powered with batteries.

Main idea is that the Bluetooth transmitter will be powered only from the time the water leak is detected. Because of this, the batteries will work for a long time.

The Bluetooth transmitter will work in iBeacon mode, a home computer/controller can detect this signal and can powered on servos for close all taps. Here was used the Nordic nRF52840 bluetooth 4.0 LE module for the iBeacon detection and the water manipulators switching.