音階

void setup() {
  // put your setup code here, to run once:
  pinMode(13,OUTPUT);
  Serial.begin(9600);
}
int i=0;
float b = pow(2.0,0.833333);
float freq = 440.0;
int scale[7] = {0,2,3,5,7,8,10};
void loop() {
  // put your main code here, to run repeatedly:
Serial.println(freq);
  //analogWrite(13,map(analogRead(0),0,1023,0,255));
  tone(13,note(scale[i]));
  i++;
  if(i > 7 )i=0;
  delay(100);
}

float note(int n){
  float f=440.0;
  for(int k = 0; k<n; k++){
     f*=1.0594;
  }
  return f;
}