3-Tone Song Player

3-tone-song-player.ino

const int BUZZ_PIN = 3;

const int NUM_LED_PINS = 4;
const int LED_PINS[NUM_LED_PINS] = {13, 13, 12, 10};

const int SONG_DELAY = 1000;
const int TONES[4] = { 400, 600, 800, 1000 };

const unsigned long BEAT_LENGTH = 90000;
const int BEAT_DELAY = 175;

// Mary Had a Little Lamb (kind of)
const int SONG_NUM_NOTES = 29;
const int SONG[SONG_NUM_NOTES][2]  = {
  {1, 1},
  {2, 1},
  {3, 1},
  {2, 1},
  {1, 1},
  {1, 1},
  {1, 2},

  {2, 1},
  {2, 1},
  {2, 2},

  {2, 1},
  {1, 1},
  {0, 2},

  {1, 1},
  {2, 1},
  {3, 1},
  {2, 1},
  {1, 1},
  {1, 1},
  {1, 1},
  {1, 1},
  {2, 1},
  {2, 1},
  {1, 1},
  {2, 1},
  {3, 4}
};

void setup() {
  pinMode(BUZZ_PIN, OUTPUT);

  for (int i = 0; i < NUM_LED_PINS; i++) {
    pinMode(LED_PINS[i], OUTPUT);
  }
}

void loop() {
  for (int i = 0; i < SONG_NUM_NOTES; i++) {
    playTone(SONG[i][0], SONG[i][1]);
  }

  delay(SONG_DELAY);
}

void playTone(int toneIndex, unsigned long duration) {
  digitalWrite(LED_PINS[toneIndex], HIGH);
  
  unsigned long beatEndTime = micros() + BEAT_LENGTH * duration;

  while (micros() < beatEndTime) {
    digitalWrite(BUZZ_PIN, HIGH);
    delayMicroseconds(TONES[toneIndex]);
    digitalWrite(BUZZ_PIN, LOW);
    delayMicroseconds(TONES[toneIndex]);
  }

  digitalWrite(LED_PINS[toneIndex], LOW);

  delay(BEAT_DELAY);
}