Reference

Principle

Compared with the resistive sensor, the capacitive soil moisture sensor solves the problem that the resistive sensor is easily corroded, and can be inserted into the soil for a long time without being corroded. The sensor has increased waterproof performance, and the sensor can still be used normally after being immersed in water; the length of the capacitive electrode plate is increased, and the soil moisture information can be measured more accurately. The sensor has a wide input voltage and can work in a wide voltage range of 3.3V-5.5V. Compatible with Arduino, ESP32, micro:bit, control board, Raspberry Pi and other common control boards. The standard designed DFRobot-Gravity interface can be directly connected to the Gavity IO expansion board. A micro PC such as a Raspberry Pi requires an external ADC (analog signal to digital signal) module to work.