Abstract: A system to signal proximity of at least one object or entity comprises reference means, sensing means for sensing the at least one object or entity in an electric field, and processing means for detecting at least one capacitive change in at least a portion of the electric field. The sensing means is configured to at least partially form the electric field with at least a portion of the reference means. Also provided is a sensing device comprising at least one electrically conductive unit, at least one reference, and an electrical circuit coupled to at least one processor. At least one of the electric circuit and the at least one processor is configured to cause the at least one electrically conductive unit and the at least one reference to form a capacitive relationship, and detect a capacitive change in at least a portion of the electrical field.

Abstract: An access control system for a passageway having a passageway barrier including an active infrared sensor device and a locking mechanism for selectively locking and unlocking the passageway barrier. The active infrared sensor device includes an infrared emitter, an infrared receiver having one or more position-sensing photodetectors operative for receiving infrared light and generating a signal corresponding to a position and/or intensity of the reflected infrared light, and a processing unit operative for detecting a change between a first signal generated by one or more position-sensing photodetectors after receiving reflected infrared light at a first location on one or more position-sensing photodetectors and a second signal generated by one or more position-sensing photodetectors after receiving infrared light reflected in response to the object moving into the surveillance area and for controlling an operation of a locking mechanism based on the change.