def distance_centimeters_continuous(self):
"""
Measurement of the distance detected by the sensor,
in centimeters.
The sensor will continue to take measurements so
they are available for future reads.
Prefer using the equivalent :meth:`UltrasonicSensor.distance_centimeters` property.
"""
self._ensure_mode(self.MODE_US_DIST_CM)
value = self.connector.get_value()
return value if value == -1 else value * get_cm_multiplier()
def distance_centimeters_ping(self):
"""
Measurement of the distance detected by the sensor,
in centimeters.
The sensor will take a single measurement then stop
broadcasting.
If you use this property too frequently (e.g. every
100msec), the sensor will sometimes lock up and writing
to the mode attribute will return an error. A delay of
250msec between each usage seems sufficient to keep the
sensor from locking up.
"""
# This mode is special; setting the mode causes the sensor to send out
# a "ping", but the mode isn't actually changed.
self.mode = self.MODE_US_SI_CM
value = self.connector.get_value()
return value if value == -1 else value * get_cm_multiplier()