Intrusion alarm sensing unit
US5216410A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 1990 |
| Grant date | Jun 1, 1993 |
| Priority date | — |
| Expiry date | Nov 16, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/16
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The present invention is directed to an intrusion detection system having two different types of motion sensors and processing of the signals produced by the motion sensors in a manner to provide a reliable indication of motion within the space being sensed. The intrusion detection system includes a microprocessor and produces an alarm signal if each sensor is activated within a predetermined time period of each other. The unit is also capable of producing what is referred to as a "trouble" signal, based upon a certain number of unconfirmed event signals, i.e. a signal from only one sensor being received, within a predetermined time, indicating that one of the sensors is not operating properly. Once a certain number of unconfirmed event signals are received, the unit operates in one of at least two different default modes whereby a trouble signal or trouble signal and alarm signal are produced by means of a different logic processing step. The invention is also directed to an intrusion detection system having dual sensors where the user can automatically reset the unit should the system have gone into default mode operation. This is particularly useful in that it reduces service on…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.