The Soil Moisture Sensor (Hygrometer Module) allows microcontrollers to measure volumetric water content in soil. The system consists of two parts: a two-pronged fork probe inserted directly into the soil and an electronic control board driven by an LM393 high-precision comparator IC.

The probe acts as a variable resistor. When the soil is dry, resistance is high, causing the digital pin (DO) to stay HIGH. When water content rises, soil conductivity increases, resistance drops, and the signal switches LOW. You can adjust the exact switching threshold with the onboard potentiometer or read continuous raw values from the analog pin (AO).

Technical Specifications

Pinout Description

• VCC: 3.3V – 5V Power Supply input.

• GND: Ground connection.

• DO (Digital Output): Outputs HIGH when soil is dry (below threshold) and LOW when moisture exceeds the threshold.

• AO (Analog Output): Provides continuous analog voltage corresponding to real-time moisture levels (higher value = drier soil).

Basic Arduino Connection & Example Code

Wiring

• VCC ➔ Arduino 5V

• GND ➔ Arduino GND

• AO ➔ Arduino Analog Pin A0

• DO ➔ Arduino Digital Pin 2

// Soil Moisture Sensor Example Code
const int analogPin = A0;
const int digitalPin = 2;

void setup() {
  Serial.begin(9600);
  pinMode(digitalPin, INPUT);
}

void loop() {
  int sensorValue = analogRead(analogPin);
  int digitalState = digitalRead(digitalPin);

  Serial.print("Analog Moisture Reading: ");
  Serial.print(sensorValue);
  Serial.print(" | Digital Status: ");
  Serial.println(digitalState == LOW ? "WET" : "DRY");

  delay(1000);
}

Why Buy From Aryabot?

• Quality Assured: Pre-tested modules with calibrated comparator responses and corrosion-resistant probe traces.

• GST Invoice Provided: Tax-compliant B2B invoices generated for commercial projects, institutional research labs, and academic orders.

• Pan-India Dispatch: Express shipping directly from our Noida distribution warehouse.