Rain8 Rain Sensor
There is nothing more embarrassing, or more wasteful or costly than an irrigation system that runs when it doesn't have to -- in the rain.
A rain sensor is a device or switch that overrides the automatic irrigation system when rainfall occurs. The sensor shuts off a system if it is operating during a rain shower, or is scheduled to run the following day and it has recently rained. It will also return the system to its regular operation during normal weather conditions.
Mini-Clik shuts sprinklers off in a storm and keeps them off, automatically compensating for the amount of rainfall that occurred. Disks absorb water and then expand proportionally to the amount of rain that fell (e.g., a small cloudburst would result in little absorption, a thunderstorm with 6" of rain would lead to more absorption and thus more expansion). As the moisture-laden disks expand, they eventually activate a switch that interrupts the circuit from the controller to the solenoid valves. Once dry, they contract and release the switch. Thus, the sensor automatically resets without ever affecting your controller.
This logical "don't water when it's raining" device can save from 25-40 percent in outdoor water use and reduce your water bills.