Components

Arduino Uno
HC-SR04 ultrasonic sensor

All these components are available in the Innovice Arduino Starter Kit.

Obstacle Detection is a crucial application of ultrasonic sensors.

Wiring

VCC → 5V
GND → GND
TRIG → Pin 9
ECHO → Pin 10

💻 Code

int trigPin = 9;
int echoPin = 10;void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}void loop() {
  long duration;
  int distance;  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");  delay(500);
}