Harley L. Heaton - Manassas VA
Michael R. Arneson - Westminster MD
Guy P. LaRocca - Centreville VA
Atlantic Research Corporation - Alexandria VA
A tamper-proof device for detecting opening and closing events of a secure container is characterized by a fiber optic cable having a first portion connected with a fixed member of the container and a second portion connected with a movable locking member of the container so that the cable is bent or flexed when the container locking member is moved between open and closed positions. Light pulses are transmitted through the cable and variations in the pulses resulting from bending of the cable are detected to indicate opening and closing of the container.