Method and apparatus for detecting direction and speed using PIR sensor
US5291020A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 7, 1992 |
| Grant date | Mar 1, 1994 |
| Priority date | — |
| Expiry date | Jan 7, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/191
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A dual pyroelectric-effect sensor having the sensing elements aligned in a motion plane permits direction determinations to be made for moving IR sources. Dual sensing-element PIR sensors provide different voltage outputs depending upon a relative direction of movement of an object and the sensing elements. By alternating the effective polarizations of the sensing elements in the PIR sensor, clear direction information is available from the PIR sensor. A direction detecting circuit working in cooperation with a switch controller employing a counter and a timer, permits independent tallying of entrances and exits. Upon the counter indicating that the number of objects that exited the area equals the number of objects that entered, the lights are immediately extinguished. The timer ensures that the lights turn off should incorrect values become recorded in the counter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.