photoelectric sensor
A photoelectric sensor is a device that converts light energy into electrical signals. The main functions of photoelectric sensors are to sense whether an object is present or absent, to measure the distance to an object, and to monitor the color or transparency of objects. Technological features of the sensor include ability to operate over a wide range of distances, high accuracy and long life in difficult environmental conditions. These features make it suitable for numerous applications in fields such as manufacturing, packaging and delivery, or automation. Depending on the type of sensor used, when an object passes between the emitter and receiver, the path of the light beam may be interrupted; that is referred to as sensing. In another example, an object that steps too close for a proximity sensor will disturb its shielding and cause it to trigger.