#define NOTE_C4  261
#define NOTE_D4  294
#define NOTE_E4  329
#define NOTE_F4  349
#define NOTE_G4  392
#define NOTE_A4  440
#define NOTE_B4  493
#define NOTE_C5  523

const int buzzerPin = 12; // Pin buzzer 
 
void setup() { 
  pinMode(buzzerPin, OUTPUT); 
} 
 
void loop() { 
  // Memainkan melodi palang pintu kereta api
  playMelody(); 
} 
 
void playTone(int frequency, int duration) { 
  for (long i = 0; i < duration * 1000L; i += frequency * 2) { 
    digitalWrite(buzzerPin, HIGH); 
    delayMicroseconds(frequency); 
    digitalWrite(buzzerPin, LOW); 
    delayMicroseconds(frequency); 
  } 
} 
 
void playMelody() { 
  int melody[] = { 
    NOTE_C5, NOTE_G4, NOTE_C5, NOTE_G4, 
    NOTE_C5, NOTE_G4, NOTE_C5, NOTE_G4, 
    NOTE_C5, NOTE_G4, NOTE_C5, NOTE_G4, 
    NOTE_C5, NOTE_G4, NOTE_C5, NOTE_G4
  }; 
 
  int noteDurations[] = { 
    8, 8, 8, 8, 
    8, 8, 8, 8, 
    8, 8, 8, 8, 
    8, 8, 8, 8
  }; 
 
  for (int i = 0; i < sizeof(melody) / sizeof(melody[0]); i++) { 
    playTone(melody[i], noteDurations[i] * 125); 
    delay(noteDurations[i] * 1.30); 
  } 
}