The OPB706A is a Reflective Object Sensor consist of an infrared light emitting diode (LED) and an NPN silicon phototransistor mounted "side-by-side" on parallel axes in a black plastic housing. The LED and phototransistor is moulded using dark infrared transmissive plastic to reduce ambient light noise. The phototransistor responds to light from the emitter when a reflective object passes within its field of view of the device.
