const int Buzzer = 13;
const int LampuMerah = 12;
const int LampuKuning = 11;
const int LampuHijau = 10;
const int TrigPin = 9;
const int EchoPin = 8;

void setup() {
  // put your setup code here, to run once:
pinMode(Buzzer, OUTPUT);
pinMode(LampuMerah, OUTPUT);
pinMode(LampuKuning, OUTPUT);
pinMode(LampuHijau, OUTPUT);
pinMode(TrigPin, OUTPUT);
pinMode(EchoPin, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
long waktu, jarak;

digitalWrite(TrigPin, LOW);
delayMicroseconds(2);
digitalWrite(TrigPin, HIGH);
delayMicroseconds(10);
digitalWrite(TrigPin, LOW);

waktu = pulseIn(EchoPin, HIGH);
jarak = 0.034 * waktu / 2;

if ((jarak <=150) && (jarak >=100)) {
  digitalWrite(LampuMerah, HIGH);
  digitalWrite(LampuKuning, LOW);
  digitalWrite(LampuHijau, LOW);
  tone(Buzzer, 500);
}
else if ((jarak <= 100) && (jarak >= 50)){
  digitalWrite(LampuMerah, HIGH);
  digitalWrite(LampuKuning, HIGH);
  digitalWrite(LampuHijau, LOW);
  tone(Buzzer, 750);
}
else if (jarak < 50){
  digitalWrite(LampuMerah, HIGH);
  digitalWrite(LampuKuning, HIGH);
  digitalWrite(LampuHijau, HIGH);
  tone(Buzzer, 1000);
}
else if (jarak > 150){
  digitalWrite(LampuMerah, LOW);
  digitalWrite(LampuKuning, LOW);
  digitalWrite(LampuHijau , LOW);
  noTone(Buzzer);
}
}