Infrared (IR) Presence Sensors on Swinging Doors

This page provides technical details of a serious design flaw inherent in a certain class of active infrared (IR) presence sensors currently in wide use on automatic swinging pedestrian doors within the United States. Two typical examples of sensors in this class are the SentrexTM sensor manufactured by Stanley Access Technologies and the VisionPulseTM sensor manufactured by Besam, Inc.   The design flaw, which has contributed to the death of at least one person struck by a door using such a sensor, is inherent in the technology and cannot be avoided by any simple means.

The problems presented by this class of sensor are the subject of an "I-team" report by Jilda Unruh, aired by WCCO-TV, Minneapolis, MN, on November 10, 1998, a special report by Inside Edition aired on September 21, 1999, and in other recent reports, both aired and forthcoming, by a number of TV stations across the U.S.


Learn how the sensors work, and the genesis and background of the problem.
Identify poorly detected materials using an inexpensive IR reflectometer you can construct yourself.

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