A solution with the sensor operating as a two-way or reflective barrier should always be preferred when the object to be scanned absorbs the sound waves or, due to its shape or position in the tray, deflects the sound waves away. In this situation an additional reflector is positioned behind the actual object to be scanned. An ultrasonic sensor with switched output and operating in window mode emits a signal as soon as the object obscures the reflector. The lpc+ in the M18 threaded housing is ideal for this purpose.
