How to Use HY-SRF05: Examples, Pinouts, and Specs

The HY-SRF05 is an ultrasonic distance sensor manufactured by Raspberry Pi 4, with the part ID "Ultrasonic distance sensor." This sensor uses sonar technology to measure the distance to an object by emitting ultrasonic waves and calculating the time it takes for the echo to return. The HY-SRF05 is widely used in robotics, automation, and obstacle detection systems due to its accuracy, reliability, and ease of use.

• Obstacle detection in robotics
• Distance measurement in automation systems
• Parking assistance systems
• Object tracking and proximity sensing
• Smart home applications (e.g., motion detection)

The HY-SRF05 is designed to provide accurate distance measurements with minimal power consumption. Below are its key technical details:

The HY-SRF05 has a 5-pin interface. Below is the pinout and description:

The HY-SRF05 is simple to use in a circuit. Follow the steps below to integrate it into your project:

1. Power the Sensor: Connect the VCC pin to a 5V power source and the GND pin to ground.
2. Trigger Signal: Connect the Trig pin to a digital output pin of your microcontroller (e.g., Arduino UNO).
3. Echo Signal: Connect the Echo pin to a digital input pin of your microcontroller.
4. Optional Pin: Leave the OUT pin unconnected unless you need to use it for specific configurations.

• Ensure the sensor is mounted securely and aligned properly for accurate measurements.
• Avoid placing the sensor near ultrasonic noise sources, as this may interfere with its operation.
• Use a resistor divider or level shifter if interfacing with a 3.3V microcontroller to avoid damaging the Echo pin.

Below is an example Arduino sketch to measure distance using the HY-SRF05:

// Define pins for the HY-SRF05 sensor
const int trigPin = 9;  // Trigger pin connected to digital pin 9
const int echoPin = 10; // Echo pin connected to digital pin 10

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(9600);
  
  // Set pin modes
  pinMode(trigPin, OUTPUT); // Set trigger pin as output
  pinMode(echoPin, INPUT);  // Set echo pin as input
}

void loop() {
  // Send a 10 µs pulse to the trigger pin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Measure the duration of the echo pulse
  long duration = pulseIn(echoPin, HIGH);

  // Calculate the distance in centimeters
  // Speed of sound = 343 m/s or 0.0343 cm/µs
  // Distance = (duration / 2) * 0.0343
  float distance = (duration / 2.0) * 0.0343;

  // Print the distance to the Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Wait before the next measurement
  delay(100);
}

• The pulseIn() function measures the time (in microseconds) for which the Echo pin remains HIGH.
• The distance is calculated by dividing the duration by 2 (to account for the round trip of the sound wave) and multiplying by the speed of sound in cm/µs.

1. No Output or Incorrect Distance

   • Cause: Improper wiring or loose connections.
   • Solution: Double-check all connections and ensure the sensor is powered correctly.

2. Unstable or Fluctuating Readings

   • Cause: Electrical noise or interference.
   • Solution: Use decoupling capacitors near the power pins and ensure the sensor is not near ultrasonic noise sources.

3. Distance Always Reads Maximum (400 cm)

   • Cause: No object within range or incorrect trigger signal.
   • Solution: Ensure an object is within the sensor's range and verify the trigger signal timing.

4. Sensor Not Responding

   • Cause: Faulty sensor or incorrect pin configuration.
   • Solution: Test the sensor with a different microcontroller and verify the pin connections.

1. Can the HY-SRF05 work with a 3.3V microcontroller?

   • Yes, but you need a level shifter or resistor divider for the Echo pin to avoid damaging the microcontroller.

2. What is the maximum range of the HY-SRF05?

   • The sensor can measure distances up to 400 cm (4 meters).

3. Can the HY-SRF05 detect transparent objects?

   • No, the sensor may struggle to detect transparent or very small objects due to poor ultrasonic wave reflection.

4. How accurate is the HY-SRF05?

   • The sensor has a resolution of 0.3 cm, but environmental factors may slightly affect accuracy.

By following this documentation, you can effectively integrate the HY-SRF05 ultrasonic distance sensor into your projects and troubleshoot common issues.