Intruder detection system with programmable countdown timer for self-supervision
US5083106A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 11, 1991 |
| Grant date | Jan 21, 1992 |
| Priority date | — |
| Expiry date | Feb 11, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/183
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An intruder detection system includes a self-supervision feature which, on the basis of detecting authorized pedestrian traffic within a region under surveillance, alerts the system user of potentially faulty system components. Such system comprises a programmable timer which is repeatedly reset to a programmed maximum time interval by each occurence of an alarm-producing event, such as a disturbance of standing microwaves and/or a slight increase in ambient temperature in a region under surveillance. During "disarm" periods when the system alarm is intentionally deactivated to enable use of the protected region without the production of any alarm signals, each occurence of an alarm input to the system alarm (as produced by authorized traffic within the protected region) is used to repeatedly reset the timer to its preselected time interval (e.g., 1,4,8 or 16 days). In the absence of an alarm input within the programmed time interval, the timer times out and activates a "trouble" alarm, alterting the system user of a potential sensor failure. Preferably, the timer's countdown is halted or interrupted during periods when the system is "armed".
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.