Ultra Sonic Sensor

 //created by arduino demon

#define echoPin 2 // attach pin D2 Arduino to pin Echo of HC-SR04

#define trigPin 3 //attach pin D3 Arduino to pin Trig of HC-SR04

// defines variables

long duration; 

int distance; 

void setup() {

  pinMode(trigPin, OUTPUT); 

  pinMode(echoPin, INPUT); 

  Serial.begin(9600); 

  Serial.println("Ultrasonic Sensor HC-SR04 Test"); 

  Serial.println("with Arduino UNO R3");

}

void loop() {

  

  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");

}