Measuring distances is a common requirement in various projects, from robotics to home automation. In the Arduino environment, one of the most popular methods for measuring distance is using ultrasonic sensors. These sensors are affordable, easy to use, and provide reasonably accurate measurements. This article will guide you through the process of setting up an ultrasonic sensor with an Arduino to measure distances.

Ultrasonic Sensor Overview

An ultrasonic sensor works by emitting a high-frequency sound wave and measuring the time it takes for the echo to return. The most commonly used sensor for this purpose is the HC-SR04. It has four pins: VCC, Trig, Echo, and GND.

Required Components

• Arduino Uno (or any compatible board)
• HC-SR04 Ultrasonic Sensor
• Jumper wires
• Breadboard

Wiring the Components

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 the 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.

Sample Code

Here is a simple Arduino sketch to measure distance using the HC-SR04 sensor:

const int trigPin = 9;
const int echoPin = 10;

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop() {
  long duration;
  int distance;

  // Clear the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Set the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);

  // Calculate the distance
  distance = duration * 0.034 / 2;

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

  delay(500);
}

Explanation

• Triggering the Sensor: The sensor is triggered by sending a 10 microsecond pulse to the Trig pin.
• Reading the Echo: The Echo pin goes HIGH for the time it takes for the emitted ultrasonic wave to return.
• Calculating Distance: The distance is calculated based on the time duration using the speed of sound (approximately 343 meters per second). The formula used is distance = duration * 0.034 / 2, where 0.034 cm/µs is the speed of sound in air.

Conclusion

Using an ultrasonic sensor with Arduino is a straightforward and effective way to measure distances. This setup can be used in a variety of projects, including obstacle avoidance in robots, level measurement in tanks, and more.