Abstract: An apparatus and method for detecting the presence of a heat emitting body within a region provides for the mounting of a cylindrical shroud having an apertured circumference within the fields of view of an infrared sensor responsive to changes in thermal energy received as a heat emitting body enters the fields of view. The motion of the heat emitting body through the fields of view provides different levels of radiation received at the sensor thereby developing a current imbalance at the output of the sensor which is used to actuate switching circuitry for controlling an appliance which is to be actuated upon entry of a heat emitting body into the field of view of the sensor.