int led=13;
int trig=8;
int echo=7;
int duration;
int distance;
void setup() {
  // put your setup code here, to run once:
  pinMode(led,OUTPUT);
  Serial.begin(9600);

}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(trig,HIGH);
delayMicroseconds(10);
digitalWrite(trig,LOW);
duration=pulseIn(echo,HIGH);
distance = duration*0.034/2;
Serial.print("DISTANCE:");
Serial.println(distance);  
}