A photoelectric switch sensor features light intensity fluctuations into electrical signal and switching actions. There are three types: diffuse (the target reflects the light back to the source), retroreflective (the light emitter and receiver are in one unit with a reflector), and through-beam (the emitter and receiver are separate devices). For logistics package detection and woodworking saw blade safeties, it is adjustable to different detection levels (light received – light on, light not received – dark on) to meet various application needs.