How to Use YL-69 Module LM393: Examples, Pinouts, and Specs

The YL-69 Module LM393 is a soil moisture sensor designed to measure the moisture content of soil, making it an essential tool for agriculture, gardening, and environmental monitoring. The module uses an LM393 comparator to provide a digital output when the soil moisture level crosses a certain threshold, which can be adjusted using an onboard potentiometer. It can also provide an analog output that gives a variable voltage depending on the moisture level.

• Automated watering systems for plants
• Soil moisture monitoring in agricultural fields
• Environmental sensing in smart home systems
• Educational projects related to plant growth and soil conditions

• Operating Voltage: 3.3V to 5V
• Output Type: Digital (D0) and Analog (A0)
• Comparator: LM393
• Sensitivity: Adjustable via onboard potentiometer
• PCB Size: Approximately 30mm x 16mm

1. Connect the VCC pin to a 3.3V-5V power supply.
2. Connect the GND pin to the ground of the power supply.
3. Connect the A0 pin to an analog input of a microcontroller to read the moisture level as an analog value.
4. Connect the D0 pin to a digital input of a microcontroller if you wish to use the digital output.

• Avoid submerging the sensor completely in water to prevent corrosion.
• Calibrate the sensor by adjusting the onboard potentiometer to set the threshold for the digital output.
• Use a pull-up resistor if the digital output is left floating.
• For more accurate readings, take multiple samples and calculate the average.

// Define the sensor pins
const int analogPin = A0; // Analog output from the sensor
const int digitalPin = 2; // Digital output from the sensor

void setup() {
  Serial.begin(9600);       // Start serial communication at 9600 baud
  pinMode(digitalPin, INPUT); // Set the digital pin as input
}

void loop() {
  int analogValue = analogRead(analogPin); // Read the analog value
  bool isDry = digitalRead(digitalPin);    // Read the digital value

  // Print the analog value to the serial monitor
  Serial.print("Moisture Level (Analog): ");
  Serial.println(analogValue);

  // Print the digital status to the serial monitor
  Serial.print("Is the soil dry? (Digital): ");
  Serial.println(isDry ? "Yes" : "No");

  delay(1000); // Wait for a second before reading again
}

• Inconsistent Readings: Ensure that the sensor is inserted into the soil properly and that the soil is uniformly moist.
• Corrosion of Probes: Minimize the time the sensor is powered to reduce corrosion, and consider waterproofing the sensor.
• No Output: Check connections and ensure the power supply is within the specified range.

• If the digital output does not change, adjust the onboard potentiometer until the desired threshold is reached.
• Clean the sensor probes regularly to maintain accuracy.
• If the sensor is not recognized by the microcontroller, ensure that the correct pins are used and that the board is properly powered.

Q: Can the YL-69 Module be used with a 5V system? A: Yes, the module can operate with a 3.3V to 5V power supply.

Q: How do I know if the sensor is working correctly? A: Test the sensor by placing it in dry soil and slowly adding water. The analog value should increase, and the digital output should change when the threshold is crossed.

Q: Is it possible to use the sensor without an Arduino? A: Yes, the sensor can be used with any microcontroller that has analog and digital input pins.

Q: How long do the sensor probes last? A: The lifespan of the probes depends on usage and environmental conditions. Regular cleaning and minimizing exposure to moisture can extend their life.

Q: Can the sensor be left in the soil permanently? A: While the sensor can be left in the soil, prolonged exposure to moisture can lead to corrosion. It's recommended to only power the sensor when measurements are needed.