const int buzzerPin = 21;  // Pin yang sesuai untuk buzzer

void setup() {
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  int lowFrequency = 440;  // Frekuensi rendah (A4)
  int highFrequency = 550; // Frekuensi tinggi (A5)
  int duration = 500;      // Durasi tiap nada dalam milidetik

  // Nada sirine naik
  for (int i = lowFrequency; i <= highFrequency; i += 10) {
    tone(buzzerPin, i, duration);
    delay(duration);
  }

  // Nada sirine turun
  for (int i = highFrequency; i >= lowFrequency; i -= 10) {
    tone(buzzerPin, i, duration);
    delay(duration);
  }

  delay(1000); // Tunggu 1 detik sebelum memutar ulang
}