Ultrasonic sensors, unlike photoelectric sensors, are often used on clear objects. An ultrasonic sensor emits an ultrasonic sound that bounces off the target and returns to the sensor. Clear objects are detected the same as opaque objects in this scenario. They can operate at comparably long distances and quite accurately. With an analog output they can measure distance with less than 1 mm resolution. ISE Controls has an extensive history of applying ultrasonic sensors in a variety of applications and in a variety environments. Contact ISE Controls, in Indianapolis, Indiana, for assistance in selecting the correct ultrasonic for you.