The present invention is directed, in part, to a receiver for an infrared light source. The receiver comprises a substantially transparent body; a sensor for receiving infrared light; and a substantially planar first surface on the transparent body. The first surface is configured to direct light from the infrared light source to the sensor. The substantially planar first surface comprises the end of the substantially transparent body. The substantially planar first surface provides an internally reflective surface that directs light into the interior of the substantially transparent body so it will make contact with the sensor.