Rain sensor for irrigation systems: what it is, applications, how it works

The rain sensor activates irrigation to provide moisture to the lawn or vegetable garden during dry periods. When it rains, its signal turns off the irrigation system. This reduces the likelihood of overwatering. There are several types of these devices.

Types of Rain Sensors

Rain sensors differ in design and how they detect precipitation. All such devices respond to the presence of rainwater. When a certain amount of precipitation is reached, the power supply to the irrigation system is stopped. When the liquid dries out, the power supply is activated and irrigation resumes. Here is a link to see prices for rain sensors.

Rain sensor with expanding disc

In the body of the device there is an element made of cork material. In its upper part there is a bowl into which the droplets flow. From there, the liquid seeps through a hole into the cork material and soaks it up. It swells and presses the switch. The electrical circuit opens and the water supply stops.

When the precipitation stops, the cork dries out, shrinks in volume, and releases the switch. The electric circuit closes. The water supply to the irrigation system is activated. At this point, the soil is dry and irrigation is needed.

Rain Sensor with Bowl

A small bowl is connected to the controller of the irrigation system. When the rainwater reaches a certain level in the bowl, the sensor detects this and turns off the irrigation system. When the liquid in the bowl evaporates, irrigation is activated. The natural evaporation of water from the sensor bowl coincides with the drying of the soil on the property.

Rain sensor with electrodes

In a bowl connected to the controller, two electrodes are placed. When rainwater reaches their level, the circuit closes and the artificial irrigation stops. When the liquid evaporates, the electrodes become an open circuit and the irrigation system is activated.

Rain sensors come in two types of connections:

• Wired sensors are wired to the irrigation system's power system, placed near the controller. It is important to install such a sensor according to the instructions so that irrigation will not be shut off prematurely in remote areas.
• Wireless sensors are self-contained, battery-operated devices. They transmit a signal over a radio link and can be at a distance from the controller. Battery monitoring is required.

Some models of rain sensor are combined with a temperature sensor. They regulate irrigation depending on the season. The device is provided with a remote control, on which you can select the irrigation mode and program irrigation.

A few features for installing and setting the rain sensors

The rain sensors are equipped with controls where you can set the threshold for triggering depending on different values of the amount of precipitation: 3 mm, 6 mm, 9 mm, 12 mm. This allows you to adjust irrigation according to the needs of plants for irrigation.

Any type of sensors has a peculiarity in maintenance. It is necessary to clean the bowls and drip catchers of debris. Otherwise, its weight may cause the irrigation system to shut down as if rainwater was collecting in the bowl.

For the rain sensor to work properly, you need to install it where it can capture the natural precipitation. If you place it inside the gutter or next to it, the device will receive an excessive amount of liquid. This will cause the irrigation system to shut down prematurely.

Excess dampness is just as dangerous to plants as drought. Prolonged dampness causes mold, fungus and root rot. In addition, adjusting irrigation with a rain sensor saves your budget during rainfall.