Soil Moisture Sensor Module

The Soil Moisture Sensor Module is a staple of smart agriculture and garden automation projects, measuring the moisture content present in soil through a simple probe-and-comparator design. The kit ships as two parts – a sensor probe that gets inserted into the soil, and a measurement module that reads the probe and outputs the result – connected together for immediate use.

The module has four pins: Vcc and Gnd for power, plus a digital output (D0) and an analog output (A0). An onboard LM393 comparator compares the probe’s reading against a threshold set via a 10K potentiometer, driving the digital pin low once soil moisture rises above that threshold, while the analog pin continuously reports a value proportional to moisture level for more granular readings. Because the comparator circuit is entirely onboard, the module can trigger an LED or buzzer directly without any microcontroller, or it can be read by an Arduino or similar board for automated monitoring and watering.

• Pin Count – 4 (VCC, GND, D0, A0)
• Comparator – LM393 op-amp comparator
• Threshold Adjustment – Onboard 10K potentiometer
• Digital Output – Logic 0 when moisture exceeds threshold
• Analog Output – Proportional to soil moisture level
• Standalone Operation – Works without a microcontroller
• Typical Use – Smart irrigation, garden automation, plant monitoring

Easy to wire and calibrate, the Soil Moisture Sensor Module is an essential building block for any automated watering or agriculture-monitoring project.