int speakerPin = 9;
  int length = 15;
  char notes[] = "ccggaagffeeddc";
  int beats[] = { 1,1,1,1,1,1,2,1,1,1,1,1,1,2,4};
  int tempo = 300;

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'};
  int tones[] = { 1915, 1700, 1519, 1432, 1275, 1136, 1014, 956};
  for (int i = 0; i < 8; i++) {
    if (names[i] == note) {
      playTone (tones[i], duration);
    }
  }
}

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


void loop() {
  for (int i= 0; i < length; i++) {
    if (notes[i] == ' ') {
    }
    else {
      playNote(notes[i], beats[i] * tempo);
    }
    delay(tempo /2);
  }
}