Rain sensors, which can be installed on sprinkler systems, help save water by interrupting automatically scheduled watering cycles when enough precipitation has occurred. This not only saves money, but ensures that foliage is not over-watered.
How rains sensors work:
Small discs inside the sensors absorb water and expand proportionally to the amount of rain that has fallen-so a small cloudburst would result in very small amount absorption, while a large thunderstorm would lead to more absorption and expansion. As the moisture-laden disks expand, they activate a switch that interrupts the circuit from the controller to the solenoid valves. Once dry, they contract and release the switch. The Mini-Clik® sensors automatically reset without affecting the controller system and can be set to activate when either 1/8”, 1/4”, 1/2”, 3/4” or 1” of rain hits the sensor.