CTYRZCH 12V Soil Moisture Sensor And Automatic Watering System 250V 10A AC or DC 30V 10A. Supply voltage: 12VDC. Input Current: more than 100ma. This is a simple water sensor that can be used to detect soil moisture. When soil moisture is below the set humidity, the relay will automatically pull start the spray, pump, do humidifying action. It will stop automatically when it reaches the set humidity.