#define trig 12
#define echo 7

long distance,duration;

void setup() 
{
  Serial.begin(9600);
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
}

void loop() 
{
  digitalWrite(trig,LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);

  duration=pulseIn(echo,HIGH);
  distance=duration/58.2;

  Serial.print("Distance = ");
  Serial.print(distance);
  Serial.println("cm");
}