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

int frekuensi = 250;
long jarak, waktu;

void setup() {
  // put your setup code here, to run once:
Serial. begin(9600);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
pinMode(led, OUTPUT);
pinMode(buzzer, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
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("jarak di luar jangkauan!\n");
}
delay(500);
}