int anemometerRotations = 0;
unsigned long currentTime = 0;

float fetchTemperature() {
  return 22.5; // XXX: Dummy value
}

float fetchHumidity() {
  return 60.0; // XXX: Dummy value
}

float fetchLight() {
  return 2000.4; // XXX: Dummy value
}

void anemometerInterrupt() {
  anemometerRotations++;
}

float fetchWindspeed() {
  anemometerRotations = 0;
  currentTime = millis();
  int interruptNumber = digitalPinToInterrupt(ANEMOMETER_PIN);

  attachInterrupt(interruptNumber, anemometerInterrupt, RISING);
  delay(1000 * 5);
  detachInterrupt(interruptNumber);

  return (float)anemometerRotations / 5.0 * 2.4;
}