Soil Moisture Sensor Module for Arduino — Analogue and Digital Output
This resistive soil moisture sensor measures soil conductivity through two exposed probes, with an LM393 comparator outputting a digital signal below the potentiometer-set moisture threshold and a raw analogue voltage for proportional measurement. The sensing probes and control board are separate — plug the probes into soil while keeping the PCB away from moisture. The 3.3V–5V supply range covers Arduino, ESP32, and Raspberry Pi GPIO inputs.
- Resistive probe sensing — conductivity-based moisture detection
- Digital output (DO) — active low below threshold, LM393
- Analogue output (AO) — proportional moisture voltage
- Adjustable threshold — onboard potentiometer
- Separate probe and control board
- 3.3V–5V supply
Why do resistive probes corrode, and what can you do?
Passing DC current through soil via metal probes causes electrolysis, which corrodes the probes over weeks to months. Mitigation: power the sensor only during measurements (connect VCC to an Arduino digital pin and switch it on for 100ms per reading), or replace with a capacitive soil moisture sensor which has no exposed conductors and lasts far longer in permanently buried applications.
Best for
Arduino plant watering experiments, greenhouse moisture alerts, temporary outdoor monitoring, short-term soil moisture demonstrations, and classroom sensor projects where sensor longevity is not a primary concern.
Why Kunkune
Shipped from UK stock. 60-day returns, no minimum order. Fast Royal Mail delivery.
For permanent outdoor burial where probe corrosion is a concern, the capacitive soil moisture sensor has no exposed electrodes and lasts far longer in continuously moist soil.
Buying in bulk? For orders of 10+ units, contact us for trade pricing.
