Access control system with energy-saving optical token presence sensor system
First Claim
1. An identification token reader containing an object presence sensor for detecting the presence of an object within its field of view, using an emitting radiation and receiving the reflected radiation from the said object, the identification object presence sensor generating a positive token present indication upon the onset of presentation of an object within the sensor'"'"'s field of view, the object presence sensor switching operating power to energize an identification token reader upon positive indication of token present.
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Accused Products
Abstract
An access control system having an energy-saving optical presence sensor system is provided. The access control system includes a relatively lower operating power object presence sensor system for optically sensing the presence of a token as well in addition to a relatively higher operating power token reader for reading the token. The token reader remains unpowered until a token is detected by the object presence sensor system, which is preferably always powered. Once an object is detected by the object presence sensor system, power is supplied to the token reader and the token is read. After the token has been read, power ceases to be applied to the token reader, although the object presence sensor remains powered.
52 Citations
26 Claims
- 1. An identification token reader containing an object presence sensor for detecting the presence of an object within its field of view, using an emitting radiation and receiving the reflected radiation from the said object, the identification object presence sensor generating a positive token present indication upon the onset of presentation of an object within the sensor'"'"'s field of view, the object presence sensor switching operating power to energize an identification token reader upon positive indication of token present.
- 12. A locking mechanism containing an object presence sensor for detecting the presence of an object within its field of view, using an emitting radiation and receiving the reflected radiation from the said object, the identification object presence sensor generating a positive token present indication upon the onset of presentation of an object within the sensor'"'"'s field of view, the object presence sensor switching operating power to energize an identification token reader upon positive indication of token present.
- 23. An object presence sensor for detecting the presence of objects within the detector'"'"'s field of view, containing a clock and synchronous control, and an amplifier with a switched offset null, where the object presence sensor zeroes the receiver amplifier offset null immediately preceding the radiation source pulse.
Specification