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] == ' ')
{
delay(beats[i] * tempo); // Rest
}
{
playNote(notes[i], beats[i] * tempo);
}
delay(tempo / 2); // Pause between notes
}
}