The QRD1114 is a Reflective Object Sensor consists of an infrared emitting diode and an NPN silicon photodarlington mounted side by side in a black plastic housing. The on-axis radiation of the emitter and the on-axis response of the detector are both perpendicular to the face of the QRD1114. The photodarlington responds to radiation emitted from the diode only when a reflective object or surface is in the field of view of the detector.