long average(int newest) {
  #define NUM_SAMPLES 10
  static int data[10];
  static byte index = 0;
  static long sum = 0;
  static byte count = 0;

  sum -= data[index];
  data[index] = newest;
  sum += newest;
  index++;
  index = index % NUM_SAMPLES;
  if (count < NUM_SAMPLES) count++;

  return (float)sum / count;
}