#define TRIG_PIN 5
#define ECHO_PIN 18
#define BUZZER 23

#define LED_HIJAU 19
#define LED_KUNING 21
#define LED_MERAH 22

void setup() {
  Serial.begin(115200);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  pinMode(LED_HIJAU, OUTPUT);
  pinMode(LED_KUNING, OUTPUT);
  pinMode(LED_MERAH, OUTPUT);
  pinMode(BUZZER, OUTPUT);
}

void loop() {
  // Mengirim gelombang ultrasonik
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);

  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);

  digitalWrite(TRIG_PIN, LOW);

  // Membaca lama pantulan
  long duration = pulseIn(ECHO_PIN, HIGH);

  // Menghitung jarak
  float distance = duration * 0.034 / 2;

  Serial.print("Jarak: ");
  Serial.print(distance);
  Serial.println(" cm");

// Matikan semua output dulu
digitalWrite(LED_HIJAU, LOW);
digitalWrite(LED_KUNING, LOW);
digitalWrite(LED_MERAH, LOW);
noTone(BUZZER);


// Menentukan LED dan buzzer berdasarkan jarak
if (distance > 100) {

  digitalWrite(LED_HIJAU, HIGH);

}

else if (distance >= 50) {

  digitalWrite(LED_KUNING, HIGH);

}

else {

  digitalWrite(LED_MERAH, HIGH);
  tone(BUZZER, 1000);

}

  delay(500);
}