const int trigPin = 13;  // Pin Trig pada HC-SR04
const int echoPin = 12;  // Pin Echo pada HC-SR04
const int yellowLedPin = 10;  // Pin untuk lampu LED kuning
const int redLedPin = 9;  // Pin untuk lampu LED merah
const int greenLedPin = 7;
const int buzzerPin = 8;  // Pin untuk buzzer

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(yellowLedPin, OUTPUT);
  pinMode(redLedPin, OUTPUT);
  pinMode (greenLedPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  long duration, distance;
  
  // Kirim sinyal ultrasonik
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Baca waktu echo
  duration = pulseIn(echoPin, HIGH);
  
  // Hitung jarak
  distance = duration * 0.034 / 2;

  // Tampilkan hasil di Serial Monitor
  Serial.print("Jarak: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Atur lampu dan buzzer berdasarkan jarak
  if (distance > 40) {
    digitalWrite(yellowLedPin, LOW);
    digitalWrite(redLedPin, LOW);
    digitalWrite(greenLedPin, HIGH);
    noTone(buzzerPin);
  } else if (distance > 30) {
    digitalWrite(yellowLedPin, HIGH);
    digitalWrite(redLedPin, LOW);
    digitalWrite(greenLedPin, LOW);
    noTone(buzzerPin);

  } else if (distance > 10) {
    digitalWrite(yellowLedPin, LOW);
    digitalWrite(redLedPin, HIGH);
    digitalWrite(greenLedPin, LOW);
    noTone(buzzerPin);
  } else {
    digitalWrite(yellowLedPin, LOW);
    digitalWrite(redLedPin, HIGH);
    digitalWrite(greenLedPin, LOW);
    tone(buzzerPin, 1000);
  }

  delay(200);  // Tunggu satu detik sebelum mengukur lagi
}