Ultrasonic Distance Sensors
microsonic ultrasonic level sensors are suitable for target distances from 20mm to 10m and as they measure the time of flight they can ascertain a measurement with pinpoint accuracy. Some of the sensors can even resolve the signal to a resolution of 0.025 mm. Virtually all materials which reflect sound can be detected, regardless of their color. Even transparent materials or thin foils represent no problem for an ultrasonic distance sensor.
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