Kemo Electronic M173 Soil Humidity Sensor Module Kit, 12V

The Kemo Electronic M173 Soil Humidity Sensor Module is an automated soil moisture controller designed to trigger irrigation pumps and valves when soil dries out. It operates in an automated cycle with built-in time delays and adjustable sensitivity, making it an ideal standalone control solution for gardening hobbyists, makers, and automated plant-care projects.

Automatic irrigation control

The module measures soil moisture upon power-up and activates a connected pump for 18 to 30 minutes when dry conditions are detected. Once sufficient moisture is reached, the unit pauses for 18 to 30 minutes before taking another measurement in a continuous loop.

Sensor installation and wiring

The measuring head is buried at the target soil depth and connects to the main controller using the included 2 m cable, which can be extended up to 20 m with standard 2-pole wire. The main unit features screw terminal connections and must be mounted in a dry location.

Relay switching and visual feedback

Equipped with a continuously adjustable switching threshold, the board provides three LED indicators for On, Off, and Pause status. It switches external equipment via an onboard potential-free relay contact rated up to 3 A (up to 25 V or 230 V).