arduino-speaker.ino

#define speakerOut 12
#define BASEFREQ 440

int sharp = 1;
int nope = 0;
int flat = -1;

void setup() {
  Serial.begin(9600);
  // put your setup code here, to run once:
  //pinMode(speakerOut, OUTPUT);
}

double getHertz(char note = 'c', int sharp = 0, int octave = 4) {
  Serial.print(note);
  Serial.print(sharp);
  Serial.println(octave);
  
  int toneVal;
  switch(note) {
    case 'a':
    toneVal = 0;
    break;

    case 'b':
    toneVal = 2;
    break;

    case 'c':
    toneVal = 3;
    break;

    case 'd':
    toneVal = 5;
    break;

    case 'e':
    toneVal = 7;
    break;

    case 'f':
    toneVal = 8;
    break;

    case 'g':
    toneVal = 10;
    break;

    default:
    toneVal = 0;
    break;
  }

  toneVal = toneVal + sharp;
  double twelveth = 1.0/12.0;
  double amp = pow(pow(2, twelveth), toneVal);

  Serial.println(BASEFREQ*amp*pow(2,(octave-4)));
  return BASEFREQ*amp*pow(2,(octave-4));
}

void tune(char* note, int howLong, int delayTime=0) {
  double hertz;
  Serial.println(note);
  if (note[1] == '#' || note[1] == 'b') {
    int modifier = 0;
    if (note[1] == '#') {
      modifier = 1;
    } else {
      modifier = -1;
    }
    hertz = getHertz(note[0], modifier, note[2] - '0');
  } else {
    hertz = getHertz(note[0], 0, note[1] - '0');
  }
  
  tone(speakerOut, hertz, howLong);
  delay(howLong);
  delay(delayTime);
}

void loop() {
  // put your main code here, to run repeatedly:
  tune("c4",100, 100);
  tune("d4",100, 100);
  tune("e4",100, 100);
  tune("f4",100, 100);
  tune("g4",100, 100);
  tune("a5",100, 100);
  tune("b5",100, 100);
  tune("c5",100, 100);
  delay(1000);
}