Method and apparatus for area and perimeter security with reflection counting
US4893005A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 21, 1988 |
| Grant date | Jan 9, 1990 |
| Priority date | — |
| Expiry date | Jan 21, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/187
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An apparatus and method for detecting disturbance in a protected area or perimeter by scanning the area or perimeter with a rotating beam of radiating energy, such as light, infrared, ultraviolet and the like, and counting the number of pulses at the output of a detector or sensor upon impingement on the detector or sensor of the beam reflected by each one of a plurality of reflectors disposed in the protected area or perimeter. Upon turning on the apparatus, a first pulse count corresponding to each complete revolution of the beam is stored as a pulse reference number for a "normal" state in the protected area or perimeter. In operation, the number of pulses for each revolution of the beam is continuously counted and compared to the stored reference number and an alarm is triggered as soon as the stored reference number and the counted number are unequal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.