/*
 * Happy Birthday to You
 * Coded By - http://forum.arduino.cc/index.php?topic=178460.0
 * Use BSD Clause 2 License for Distribution
 */

int speakerPin = 3;

int length = 28; // the number of notes

char notes[] = "GGAGcB GGAGdc GGxecBA yyecdc";

int beats[] = { 2, 2, 8, 8, 8, 16, 1, 2, 2, 8, 8, 8, 16, 1, 2, 2, 8, 8, 8, 8, 16, 1, 2, 2, 8, 8, 8, 16 };

int temporary = 150;

void playTone(int tone, int duration) {
  for (long i = 0; i < duration * 1000L; i += tone * 2) {
    digitalWrite(speakerPin, HIGH);
    delayMicroseconds(tone);
    digitalWrite(speakerPin, LOW);
    delayMicroseconds(tone);
  }
}

void playNote(char note, int duration) {

char names[] = {'C', 'D', 'E', 'F', 'G', 'A', 'B',           

                 'c', 'd', 'e', 'f', 'g', 'a', 'b',

                 'x', 'y' };

int tones[] = { 1915, 1700, 1519, 1432, 1275, 1136, 1014,
                 956,  834,  765,  593,  468,  346,  224,
                 655,  715 };

  int SPEE = 5;

  // play the tone corresponding to the note name
  for (int i = 0; i < 17; i++) {
    if (names[i] == note) {
      int newduration = duration/SPEE;
      playTone(tones[i], newduration);
    }
  }
}

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

void loop() {
  for (int i = 0; i < length; i++) {
    if (notes[i] == ' ') {
      delay(beats[i] * temporary);
    } else {
      playNote(notes[i], beats[i] * temporary);
    }

    // pause between notes
    delay(temporary);
  }
}