A method for dynamically calibrating automatic infrared sensing devices in commercial use having an IR detector. Randomly reflected emitted IR radiation is detected by the IR detector which sends as IR detector output to a control module. The control module measures whether the detector output is too high or too low compared to a standard range of output values stored in the control module. An IR emitter value is then determined to maintain IR detector output within the standard range of values. This IR emitter input value is stored in the control module as a calibration standard until the calibration cycle.