while GPIO.input(ECHO) == 0: pulse_start = time.time() while GPIO.input(ECHO) == 1: pulse_end = time.time()
Use a rubber gasket on the sensor head to maintain IP67 rating when installed through a panel. Do not overtighten. aj sr04m datasheet
The module requires at least 50 ms between measurements to avoid ringing interference (acoustic noise). Trying to read faster than 20 Hz may produce erratic results. while GPIO