[arduino] mesure de débattement

//----------------------------------------------------------------------------------------------------------------------------------
String cnv_flt2str(float num, int car, int digit) { // Convert a float variable into a string with a specific number of digits
  //----------------------------------------------------------------------------------------------------------------------------------
  String str = "";
  if (digit > 0) {
    str = String(num,digit);
  } else {
    str = String(int(num));
  }
  while (str.length() < car) {
    str = " " + str;
  }
  return str;
}

#define NUM_SAMPLES  150

//----------------------------------------------------------------------------------------------------------------------------------
double read_angle() {                             // Function returning the current rotation value along X axis - in degrees
  //----------------------------------------------------------------------------------------------------------------------------------
  float x, y, z;
  float y_accum = 0, z_accum = 0;
  for (int nn = 0;  nn < NUM_SAMPLES; nn++) {
    mma.getAcceleration(&x, &y, &z);
    y_accum += y;
    z_accum += z;
  }

  y = y_accum / NUM_SAMPLES;
  z = z_accum / NUM_SAMPLES;

  return atan2(y, z) / M_PI * 180;
}

unsigned long timeElapsed = (micros() - preFunction) / 1000;
Serial.println("Time :" + String(timeElapsed));
Serial.println(String(l_angle, 5) + "   -   " + String( ll_angle, 5));

Time :94
1743.00000   -   174.3

float angle = atan2(y, z) / M_PI * 180;
unsigned long timeElapsed = (micros() - preFunction) / 1000;
Serial.println("Time :" + String(timeElapsed));
Serial.println(String(angle, 5));

Time :60
174.25201

#define ALPHA        0.7

  // angle filtering
  x_rot = (last_angle * ALPHA) + (x_rot * (1 - ALPHA));
  last_angle = x_rot;