'Initialize the sensor.'

def __init__(self, name, state_topic, device_id, timeout, consider_home):

    self._state = STATE_AWAY
    self._name = name
    self._state_topic = '{}{}'.format(state_topic, '/+')
    self._device_id = slugify(device_id).upper()
    self._timeout = timeout
    self._consider_home = (timedelta(seconds=consider_home) if consider_home else None)
    self._distance = None
    self._updated = None
