How to Use Ultrasonic Distance Measurement Control Board Rangefinder 3 Bit LED Display: Examples, Pinouts, and Specs

The Ultrasonic Distance Measurement Control Board, manufactured by diymore, is an electronic device designed to measure distances using ultrasonic waves. It integrates an HC-SR04 ultrasonic sensor with an 8-bit microcontroller unit (MCU) and a 3-bit LED display to provide immediate visual feedback. This component is commonly used in robotics, obstacle avoidance systems, parking sensors, and various automation projects where precise distance measurements are required.

• Operating Voltage: 5V DC
• Current Consumption: 15 mA
• Acoustic Emission Frequency: 40 kHz
• Max Range: 4m
• Min Range: 2cm
• Resolution: 1 cm
• Measurement Angle: 15 degrees
• Display: 3-bit LED for distance indication

1. Power Supply: Connect the VCC pin to a 5V power source and the GND pin to the ground.
2. Triggering the Sensor: Send a 10 µs TTL pulse to the TRIG pin to initiate the measurement.
3. Reading the Distance: Monitor the ECHO pin; the duration of the high signal will be proportional to the distance measured.
4. Display: The 3-bit LED display will automatically show the distance measurement.

• Ensure that the power supply does not exceed 5V to avoid damaging the board.
• Avoid placing the sensor in an environment with strong ultrasonic noise to prevent false readings.
• The sensor should not be used to measure soft materials like cloth, which may absorb ultrasonic waves.
• For accurate measurements, keep the sensor perpendicular to the object being measured.

// Define the pins for the ultrasonic sensor
const int trigPin = 9;
const int echoPin = 10;

void setup() {
  // Initialize serial communication
  Serial.begin(9600);
  // Define sensor pins as input/output
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop() {
  // Clear the trigPin by setting it LOW
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Trigger the sensor by setting the trigPin high for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the echoPin; pulseIn returns the duration (length of the pulse)
  long duration = pulseIn(echoPin, HIGH);

  // Calculate the distance
  int distance = duration * 0.034 / 2; // Speed of sound wave divided by 2 (go and back)

  // Display the distance on the Serial Monitor
  Serial.print("Distance: ");
  Serial.println(distance);

  // Delay between measurements
  delay(500);
}

• No Readings: Ensure that the VCC and GND connections are secure and that the sensor is powered.
• Inaccurate Readings: Check for obstacles that may interfere with the sensor's line of sight or cause echos.
• LED Display Not Working: Verify that the LED display is correctly soldered and that there are no loose connections.

• If the sensor is not functioning, try replacing it to determine if the issue is with the sensor itself.
• For erratic readings, consider adding a filter in your code to average multiple readings.
• Ensure that the trigger pulse to the TRIG pin is exactly 10 µs as required.

Q: Can the sensor measure distances beyond 4 meters? A: No, the maximum reliable range for the HC-SR04 is 4 meters.

Q: Is it possible to use this sensor with a 3.3V system? A: The sensor is designed for 5V operation. Using it with 3.3V may result in unreliable performance or no operation at all.

Q: How can I increase the refresh rate of the sensor? A: The refresh rate can be increased by reducing the delay between measurements, but ensure that the sensor has enough time to process the signal and provide a stable reading.