void setup()

{ Serial.begin (9600);

pinMode(13, OUTPUT);

pinMode(12, INPUT);

pinMode(11, OUTPUT);

}

void loop()

{ long duration, distance;

digitalWrite(13, LOW);

delayMicroseconds(2);

digitalWrite(13, HIGH);

delayMicroseconds(10);

digitalWrite(13, LOW);

duration = pulseIn(12, HIGH);

distance = (duration/2) / 29.1;

if (distance < 10)

{ digitalWrite(11,HIGH);

}

else {

digitalWrite(11,LOW);

}

Serial.print(distance);

Serial.println(" cm");

delay(500);

}