#define trigPin 7
#define echoPin 6
#define led 13
#define buzzer 11

int frekuensi = 2000;
long jarak, waktu;

void setup()  {
Serial.begin (9600);
pinMode(trigPin, OUTPUT);
pinMode  (echoPin, INPUT);
pinMode  (buzzer, OUTPUT);
 }

void loop ()  {
digitalWrite  (trigPin, LOW);
delayMicroseconds(2);
digitalWrite  (trigPin, HIGH);
delayMicroseconds(10);
digitalWrite  (trigPin, LOW);
waktu = pulseIn  (echoPin, HIGH);
jarak = (waktu/2)  / 29.1;

 if (jarak<= 150)  {
digitalWrite  (led, HIGH);
tone(buzzer, frekuensi);
Serial.print (jarak);
Serial.print (" cm \n");
  }
  else if (jarak>150) {
digitalWrite (led, LOW);
noTone (buzzer);
Serial.print("Jarakdiluarjangkauan\n");
  }

delay(500);
 }