Fast arpeggios played to simulate chords C a d G

pwm_arpeggios.ino

int speakerPin = 26;      // speaker on digital pin 26

float frequencies[] = {
                        130.8, 164.8, 196, 130.8, 164.8, 196, 130.8, 164.8, 196, 130.8, 164.8, 196, 130.8, 164.8, 196, 130.8, 164.8, 196, 130.8, 164.8, 196, 130.8, 164.8, 196, 130.8, 164.8, 196, 130.8, 164.8, 196,
                        220, 261.6, 329.6, 220, 261.6, 329.6, 220, 261.6, 329.6, 220, 261.6, 329.6, 220, 261.6, 329.6, 220, 261.6, 329.6, 220, 261.6, 329.6, 220, 261.6, 329.6, 220, 261.6, 329.6, 220, 261.6, 329.6,
                        146.8, 174.6, 220, 146.8, 174.6, 220, 146.8, 174.6, 220, 146.8, 174.6, 220, 146.8, 174.6, 220, 146.8, 174.6, 220, 146.8, 174.6, 220, 146.8, 174.6, 220, 146.8, 174.6, 220, 146.8, 174.6, 220,
                        196, 247, 293.7, 196, 247, 293.7, 196, 247, 293.7, 196, 247, 293.7, 196, 247, 293.7, 196, 247, 293.7, 196, 247, 293.7, 196, 247, 293.7, 196, 247, 293.7, 196, 247, 293.7};
float durations[] = {
                        0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06,
                        0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06,
                        0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06,
                        0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06, 0.06};

int musicLength = sizeof(frequencies) / sizeof(frequencies[0]);

float delayInMicroseconds;
int numberOfIterations;
float frequency;
float duration;

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

for (int y=0; y < 4; y++) {
  
  for (int x=0; x < musicLength; x++) {

    frequency = frequencies[x];
    duration = durations[x];
    
    delayInMicroseconds = 1/frequency*1000000/2;
    numberOfIterations = duration*frequency;
        
    for (int f=0; f < numberOfIterations; f++) {
      digitalWrite(speakerPin, HIGH);
      delayMicroseconds(delayInMicroseconds);
      digitalWrite(speakerPin, LOW);
      delayMicroseconds(delayInMicroseconds);
    }
  }
}
}

void loop() {
}