Multiplexing a music keyboard

Other Hardware LEDs and Multiplexing
5 

// Essai du fonctionnement d'un octave du clavier.
// Pas de modification d'intensité de LED

const int led = 13;
const int M1 = 38;

// Notes
const int C = 23;
const int B = 25;
const int Ad = 27;
const int A = 29;
const int Gd = 31;
const int G = 33;
const int Fd = 35;
const int F = 37;
const int E = 41;
const int Dd = 43;
const int D = 45;
const int Cd = 47;
const int CL = 49;
const int notes[13] = {CL, Cd, D, Dd, E, F, Fd, G, Gd, A, Ad, B, C};

// Loop
int note;
int test;
boolean detecte;

void setup()
{
  int index;
  pinMode(led, OUTPUT);
  for (index = 0; index < 13; index ++)
  {
    pinMode(notes[index], OUTPUT);
  }
  digitalWrite(M1, HIGH);
  Serial.begin(9600);
  Serial.print("demarrage\n");
}

void loop()
{
  // Lecture de l'état des entrées
  detecte = false;
  for (note = 0; note < 13; note++)
  {
    test = digitalRead(notes[note]);
    if (test == HIGH)
    {
      detecte = true;
      Serial.print(note);
      Serial.print("\n");
    }
  }
  if (detecte == true)
  {
    digitalWrite(led, HIGH);
  }
  else
  {
    digitalWrite(led, LOW);
  }
}