HC-SR04 Ultrasonic Distance Sensor and Arduino (Lesson #9)

Introduction

In this tutorial, you will learn how to use the HC-SR04 ultrasonic distance sensor with an Arduino to measure the distance to nearby objects. This project is a great introduction to working with sensors and can be applied in various robotics and automation projects.

Step 1: Gather Your Materials

To get started, make sure you have the following components:

• HC-SR04 ultrasonic distance sensor
• Arduino board (e.g., Arduino Uno)
• Jumper wires
• Breadboard (optional)
• USB cable to connect Arduino to your computer

Step 2: Make the Connections

Connect the HC-SR04 to the Arduino as follows:

1. Connect the VCC pin of the HC-SR04 to the 5V pin on the Arduino.
2. Connect the GND pin of the HC-SR04 to a GND pin on the Arduino.
3. Connect the TRIG pin of the HC-SR04 to digital pin 9 on the Arduino.
4. Connect the ECHO pin of the HC-SR04 to digital pin 10 on the Arduino.

Tip: Ensure all connections are secure to avoid any interruptions in data transmission.

Step 3: Review the Datasheet

• Familiarize yourself with the HC-SR04 datasheet. It provides critical information on the sensor's specifications, including its operating voltage, range, and timing requirements.

Step 4: Write the Code

Use the following Arduino code to set up the HC-SR04 sensor:

#define TRIG_PIN 9
#define ECHO_PIN 10

void setup() {
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
}

void loop() {
  long duration, distance;
  
  // Clear the trigger
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  
  // Set the trigger high for 10 microseconds
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  
  // Read the echo pin
  duration = pulseIn(ECHO_PIN, HIGH);
  
  // Calculate distance in cm
  distance = duration * 0.034 / 2;
  
  // Print the distance
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  
  delay(500);
}

Tip: Make sure to upload the code to your Arduino using the Arduino IDE.

Step 5: Test the Sensor

• Open the Serial Monitor in the Arduino IDE to view the distance readings.
• Hold an object in front of the sensor to see how the distance changes in real-time.

Step 6: Compare HC-SR04 with PING Sensor

• Understand the differences between the HC-SR04 and the PING))) ultrasonic sensors.
  • The HC-SR04 is typically more affordable and widely used for basic applications.
  • The PING sensor provides a simpler interface but may not have the same range as the HC-SR04.

Common Pitfalls:

• Ensure that the HC-SR04 is not too close to the object you are measuring, as it has a minimum range.
• Avoid using the sensor in areas with excessive noise, which may interfere with the ultrasonic signals.

Conclusion

You have successfully set up the HC-SR04 ultrasonic distance sensor with an Arduino. This basic project can serve as a foundation for more complex applications, such as obstacle detection in robots or automatic distance measuring devices. Explore additional projects and tutorials to expand your understanding of sensors and Arduino programming.