How Does a Rain Sensor Work?

A rain sensor for your water sprinkler irrigation system is a great saver of time, money and embarrassment. Nothing looks more foolish, or is more wasteful, than timer-controlled sprinklers spraying away in a driving rainstorm. You will not always be at home to manually shut off the sprinklers every time it rains.

The Technology that Makes Rain Sensors Work

A sprinkler rain sensor operates via a gauge mounted on an external arm, that is mounted on a fence near your lawn or garden, attached to the sprinkler system. Disks inside the gauge absorb water and expand more as rain continues falling. These send a message to the sprinkler system controller, interrupting the electronic signal that turns on the sprinklers. The signal is blocked until the disks shrink again to their dry size. The sprinkler controller then receives the start signal, and resumes its spraying schedule.

Other Options For Sprinkler Control Sensors

Quick shut-off rain sensors activate at the touch of the first raindrops, using external impact-sensing monitors. Wind sensors clock high winds with motion-sensor technology, turning off water flow to the roadway or sidewalk. Programmable thermometers enable freeze sensors to terminate water flow when the air temperature approaches 32 degrees F (0 C).