DFRobot Water Leak Detector indicates water leakage to minimize and avoid damage. The sensor is based on the integrated design of NO/NC. It aims to detect water leakage and water shortage. The sensor uses a relay output signal. When it is normally open and water touches the two probes, the built-in relay will be triggered. When it is normally closed and the water level is lower than two probes, the built-in relay will be triggered. Then, the alarm system will be turned on or the equipment in the house will be switched off.