This Humidity sensor module can be used in either Digital mode, to act as a switch when the humidity level reaches below a threshold or, can be used in Analog mode to get exact readings. This soil moisture (and humidity) sensor will activate an output pin once the humidity level reaches below a certain theshold. The threshold can be fine-tuned by adjusting the onboard potentiometer to the desired value. This pin can be connected to your Arduino's Digitial Input pin. Alternatively, connect the Analog output pin directly to you Arduino's Analog input pins for more accurate readings instead. Example code can be found at https://www.instructables.com/id/Arduino-Soil-Moisture-Sensor/
