The OPB818 is a Slotted Switch that consists of an infrared emitting diode and an NPN silicon phototransistor mounted in a low-cost black plastic housing on opposite sides of a wide slot. Switching of the phototransistor occurs whenever an opaque object passes through the slot. The OPB818 is designed for direct soldering into PCBoards or for mounting in standard dual-in-line sockets and has an 0.25" (6.35 mm) deep and 0.20" (5.08 mm) wide slot. The apertures are 0.033" (0.84 mm) in diameter on both the sensor side ("S") as well as on the emitter side ("E").
Choice of aperture
Choice of opaque or IR transmissive shell material