DFRobot Gravity Analog Capacitive Soil Moisture Sensor - Corrosion Resistant

Capacitive sensors measure the dielectric constant of the soil, which correlates to water content, without exposing metal electrodes directly to the soil. This eliminates the oxidation and corrosion that plagues resistive sensors, leading to significantly longer lifespan and more stable readings over time.

Connect the sensor's Gravity 3-pin cable to your Arduino: Red to 5V, Black to GND, and Blue to an analog input pin (e.g., A0). The sensor outputs an analog voltage between 1.2V (wet soil) and 2.5V (dry soil). Use the `analogRead()` function in your sketch to obtain a value between 0 and 1023, which you can then map to a moisture percentage.

Yes. The sensor's onboard voltage regulator accepts an input range of 3.3V to 5.5V, making it fully compatible with 3.3V logic boards. When powered with 3.3V, the output analog voltage range will scale accordingly, and you can connect the signal wire directly to the MCU's 3.3V-tolerant ADC pin.

For accurate moisture percentage readings, sensor-specific calibration is recommended. Record the analog output values in completely dry air (or a dry soil sample) and in saturated, waterlogged soil. Use these minimum and maximum values in your code to map subsequent readings to a meaningful moisture percentage scale for your specific soil type.