Soil Moisture Sensor for Arduino

This is a simple moisture sensor can be used to test the moisture of soil, when the soil moisture is low, the module output is low. Use this sensor for making automatic watering of plants device.
sensitivity adjustable (shown in blue digital potentiometer control)
4 working voltage of 3.3 V - 5 V
Module double output mode, digital output is simple, analog output more accurate.
has fixed bolt hole, convenient installation
PCB size: 3 cm * 1.6 cm
The power indicator light (red) and digital switch output light (green)
comparator: LM393 chip
Pinouts:
VCC external 3.3 V - 5 V
GND external GND
DO small plate digital output interface (0 and 1)
AO small plate analog output interface