Piezo Speaker Twinkle Twinkle Little Star

/* Lightly modified to simplify the code! */

/*
Connections For this application;
Use Freeduino-RichBoard made by www.EmbeddedMarket.com
1. Connect Digital Pin 9 to Buz pin in Section 9 on Freeduino Board
2. Connect USB Cable
*/


/* Melody
 * (cleft) 2005 D. Cuartielles for K3
 *
 * This example uses a piezo speaker to play melodies.  It sends
 * a square wave of the appropriate frequency to the piezo, generating
 * the corresponding tone.
 *
 * The calculation of the tones is made following the mathematical
 * operation:
 *
 *       timeHigh = period / 2 = 1 / (2 * toneFrequency)
 *
 * where the different tones are described as in the table:
 *
 * note   frequency   period  timeHigh
 * c          261 Hz          3830  1915
 * d          294 Hz          3400  1700
 * e          329 Hz          3038  1519
 * f          349 Hz          2864  1432
 * g          392 Hz          2550  1275
 * a          440 Hz          2272  1136
 * b          493 Hz          2028  1014
 * C          523 Hz          1912  956
 *
 * http://www.arduino.cc/en/Tutorial/Melody
 */

int speakerPin = 3;

int length = 48; // the number of notes

//twinkle twinkle little star
char notes[] = "ccggaag ffeeddc ggffeed ggffeed ccggaag ffeeddc "; // a space represents a rest
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 };

  // play the tone corresponding to the note name
  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] == ' ') {
      delay(tempo); // rest
    } else {
      playNote(notes[i], tempo);
    }

    // pause between notes
    delay(tempo / 2);
  }
}