The IR sensor is configured to be mounted proximate to a door to be monitored. The IR sensor has an IR transmitter and an IR receiver. The IR transmitter has an active period and an idle period. The IR transmitter transmits control data packets which are provided by the processor during the active period. The IR receiver has an active period for detecting IR data and reflected data packets. Each of the reflected data packets has a packet IR reflectivity. The memory stores a door IR reflectivity associated with a door surface of the door, and the processor compares the packet IR reflectivity to the door IR reflectivity to determine at least a door position of the door.