Irrigation controllers can be used to control automatic watering systems from drip irrigation systems or pop up lawn sprinklers. Irrigation control systems work by regulating when water is released from you water supply and how long for, which helps to ensure that each plants is well looked after. Rain Sensors can be used to enhance the capabilities of an irrigation controller, rain sensors detect the periods of rain fall and then suspends the watering from your water supply this means that you won't be wasting water.