Personal Alarm System
Originally published in 1977
Body
Sentry Products, Inc. commercialized a personal security system based on NASA space telemetry. The heart of system is ultrasonic pen size transmitter which can be used by prison guards, teachers, and others such as the handicapped and elderly. When problem arises, be it threat of violence or medical crisis, pen transmits silent signal to nearby receiver. Within an institution, apartment or office building receiver may be one of many that are wired to a central console that will display the exact location of the emergency.
Full article: http://hdl.handle.net/hdl:2060/20070019879
Abstract
Sentry Products, Inc. commercialized a personal security system based on NASA space telemetry. The heart of system is ultrasonic pen size transmitter which can be used by prison guards, teachers, and others such as the handicapped and elderly. When problem arises, be it threat of violence or medical crisis, pen transmits silent signal to nearby receiver. Within an institution, apartment or office building receiver may be one of many that are wired to a central console that will display the exact location of the emergency.