TOOGOO(R) Soil Hygrometer Humidity Detection Module Moisture Testing Sensor for Arduino PI This is a summary of the soil moisture sensor can be used to detect moisture, when the soil is dry, the module outputs a high level, whereas output low. Using this sensor make an automatic watering system, so that your garden plants without people to manage. 100% Brand new and high quality. Operating voltage: 3.3V~5V. Adjustable sensitivity (shown in blue digital potentiometer adjustment) Dual output mode,analog output more accurate.