def _pre_put_hook(self):
sensor = Sensor.query(Sensor.sensor_id == self.sensor_id).fetch(1)
if not sensor:
sensor = Sensor(sensor_id=self.sensor_id)
sensor.put()
else:
sensor = sensor[0]
# calculate real value
if sensor.type == Sensor.DISTANCE:
v = float(self.raw) / 4096 * 3 * 1.4
self.value = 76.35 * (math.e ** (-3.469 * v)) + 17.3 * (math.e ** (-0.5599 * v))
