Wireless tether
First Claim
1. Coded article detection apparatus comprising:
- at least first and second coded articles respectively transmitting first and second preselected identification values; and
a receiver for receiving said preselected identification values including;
a non-volatile memory for storing first and second fixed predetermined values;
a detector generating a first signal when said first preselected identification value corresponds to said first fixed predetermined value and said second preselected identification value corresponds to said second fixed predetermined value; and
a timer responsive to the first signal to generate an alarm when the first signal is not generated for a predetermined time interval.
2 Assignments
0 Petitions
Accused Products
Abstract
A wireless tether serves to warn if a tethered article moves away from the tethering location, such as a child moving away from a parent, or luggage being removed from its owner, or equipment being removed from a facility. A transmitting module on each tethered article periodically transmits a low power identification signal including a coded value. A receiving module at the tethering location receives identification signals transmitted by the transmitting module(s) and compares the coded value thereof to a stored coded value predetermined to correspond to that of the particular tethered article. If there is correspondence, the tethered article is near the tethering location. If there is not correspondence within a predetermined time interval, the tethered article has moved away and an alarm is raised. The "length" of the tether is adjusted by adjusting the transmission range of the transmitting module to the receiving module. A number of non-correspondences may be permitted before raising the alarm so as to reduce false alarms. A receiving module can tether plural transmitting modules and may be arranged for such plural transmitter modules to have identification signal coded values that are the same, or that are partially or completely different.
288 Citations
34 Claims
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1. Coded article detection apparatus comprising:
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at least first and second coded articles respectively transmitting first and second preselected identification values; and a receiver for receiving said preselected identification values including; a non-volatile memory for storing first and second fixed predetermined values; a detector generating a first signal when said first preselected identification value corresponds to said first fixed predetermined value and said second preselected identification value corresponds to said second fixed predetermined value; and a timer responsive to the first signal to generate an alarm when the first signal is not generated for a predetermined time interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Coded article detection apparatus comprising:
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a plurality of coded articles each transmitting a respective preselected identification value; and a receiver for receiving said respective preselected identification values including; a detector generating a first signal when one of said respective preselected identification values corresponds to one of a set of fixed predetermined values; a latch responsive to said first signal to generate a second signal when said first signal has been generated in response to every one of the fixed predetermined values of said set of fixed predetermined values; and a timer responsive to the second signal to generate an alarm when the second signal is not generated for a predetermined time interval. - View Dependent Claims (12, 13, 14, 15)
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16. Coded article detection apparatus comprising:
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a set of coded articles each including a transmitter for transmitting a respective identification signal including a preselected coded value, wherein the set of coded articles transmits a set of preselected coded values; and detection apparatus including; a receiver for receiving identification signals, a comparator for comparing the coded value of each said received identification signal to a set of fixed predetermined values, wherein said set of fixed predetermined values are preselected to correspond to the set of preselected coded values, a detector for detecting received identification signals, wherein said detector is coupled to said receiver to enable said comparator in response to receiving an identification signal irrespective of the coded value included therein, said comparator once enabled then comparing the coded value of each said received identification signal to said set of fixed predetermined values, and a first timer coupled to said comparator for generating an alarm when the set of coded values of said received identification signals differs from said set of fixed predetermined values for a given first time interval. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. A transmitter-receiver set comprising:
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a transmitter memory containing a preselected coded identification value stored therein; a transmitter for transmitting said preselected coded identification value during a portion of each one of a sequence of time intervals; and a receiver for receiving said preselected coded identification value when said transmitter is within transmission range of said receiver; a receiver memory containing a fixed reference value stored therein; a comparator for detecting when said preselected coded identification value corresponds to said fixed reference value; a receiver timer responsive to said comparator to generate an alarm when said preselected coded identification value does not correspond to said fixed reference value for a predetermined time greater than said time interval; and a wake-up circuit responsive to the receiver receiving a coded identification value to connect said comparator to a source of electrical potential. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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30. A method of detecting absence of one of a set of articles each of which periodically transmits a preselected coded identification value comprising:
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receiving each transmitted coded identification value; comparing each received coded identification value to a set of fixed reference values, wherein said set of fixed reference values is preselected to correspond to said preselected coded identification values; generating an indication of correspondence when the received coded identification value corresponds to one of the set of fixed reference values; storing the indication of correspondence; determining when the stored indications of correspondence correspond to the set of fixed reference values; timing up to a predetermined time period; restarting said timing when the stored indications of correspondence are determined to correspond to the set of fixed reference values; and sounding an alarm when said timing reaches said predetermined time period, whereby said alarm is sounded when said timing reaches said predetermined time period before correspondence of the stored indications to the set of fixed reference values is determined. - View Dependent Claims (31, 32, 33, 34)
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Specification