Infrared intrusion alarm system with temperature responsive threshold level
US4195234A · kind A · utility
15Cited by
5References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Feb 2, 1978 |
| Grant date | Mar 25, 1980 |
| Priority date | — |
| Expiry date | Feb 2, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S250/01
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
Intrusion detector of the type in which the presence of an intruder is detected by infrared heat energy emitted by his body. An alarm signal is delivered when the level of radiation detected rises from the ambient level to a threshold level. A temperature responsive circuit adjusts the threshold level and so that the system has a relatively uniform detection range or sensitivity notwithstanding changes in the ambient temperature in the protected area.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.