Temperature-compensated object sensing device and method therefor
US5844502A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 22, 1997 |
| Grant date | Dec 1, 1998 |
| Priority date | — |
| Expiry date | Jul 22, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08G1/042
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A device and method is provided for sensing an object or vehicle in proximity to a sensing zone, wherein the device is exposed to an environment temperature. The object sensing device comprises a sensor, such as an inductive loop having a characteristic, such as the inductance of the inductive loop, responsive to the proximity of the object is to the sensor; a signal generator, such as an oscillator, coupled to the sensor for producing a first periodical signal cycling at a first frequency dependent on the sensor characteristic and the environment temperature. A de-coupling mechanism for de-coupling or isolating the sensor from the signal generator so that the signal generator produces a second periodical signal cycling at a second frequency dependent on the environment temperature, but not substantially dependent on the characteristic of the sensor; and a device for producing a temperature-compensated response indicative of whether the object is in the sensing zone from the first and second periodical signals or their respective frequencies. Using the temperature-compensated object or vehicle sensing device, a gate operating system and a vehicle driver stimulus device is also prov…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.