Laser sensors work like any photoelectric sensor, except that the emitter is a laser instead of an LED, says Wayne Meyer, product manager for SICK Inc. (Bloomington, MN). Like all photoelectrics, laser sensors can operate in opposed, proximity and retroreflective modes. And, like all photoelectrics, laser sensors can be used to detect parts or part features in switching, counting and error-proofing applications.

However, laser sensors have distinct advantages over other photoelectric sensors, thanks to the unique qualities of their light source. Lasers produce high-energy light in a tightly focused, highly collimated beam. This enables laser sensors to detect very small objects at long distances, and it lets engineers set precise switching points. The dense, powerful beam cuts through airborne particulates better than other light sources. In addition, lasers produce a clearly visible spot or line of light, which helps with aiming the sensor.