Article theft detection apparatus
First Claim
1. An alarm system comprising:
- a variable transmitter circuit having at least one transducer for emitting inaudible sound waves, the sound waves being varied based on the configuration of an area where an item to be monitored is located and the location of each transducer to substantially saturate said area;
a security tag having a receiver and an alarm coupled to the receiver, the security tag being attachable to the item to be monitored; and
the receiver being responsive to the inaudible sound waves and being operative to actuate said alarm to provide an audible signal when the receiver no longer detects the inaudible sound waves.
0 Assignments
0 Petitions
Accused Products
Abstract
A method and system are provided for monitoring an item within a defined area and sounding an alarm if the item is removed from the area. A transmitter and transducers emit ultrasound which substantially saturates the area to be monitored. A security tag having a detector and alarm is attached to the items to be monitored within the area. Sensing circuits may be additionally provided to determine whether a security tag is being tampered with or removed by an unauthorized person. The security tag'"'"'s alarm is sounded in the event that the receiver does not detect the ultrasound indicating that the monitored item is no longer in the monitored area. Additional alarms may be provided for indicating that the security tag has been tampered with or removed.
-
Citations
22 Claims
-
1. An alarm system comprising:
-
a variable transmitter circuit having at least one transducer for emitting inaudible sound waves, the sound waves being varied based on the configuration of an area where an item to be monitored is located and the location of each transducer to substantially saturate said area; a security tag having a receiver and an alarm coupled to the receiver, the security tag being attachable to the item to be monitored; and the receiver being responsive to the inaudible sound waves and being operative to actuate said alarm to provide an audible signal when the receiver no longer detects the inaudible sound waves. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method of monitoring the location of an item, comprising the steps of:
-
emitting inaudible sound waves, the sound waves being varied based on the configuration of an area to be monitored and the at least one location from which said sound waves are emitted to substantially saturate said area; attaching a security tag having a receiver and an alarm coupled to the receiver to an item to be monitored wherein the receiver is operable to detect the sound waves; and triggering said alarm when the receiver does not detect the presence of the sound waves. - View Dependent Claims (11, 12, 13, 14, 15)
-
-
16. An alarm system comprising:
-
a variable transmitter circuit for emitting inaudible sound waves; a plurality of transducers coupled to the variable transmitter circuit and arranged within a predefined area to emit the sound waves, said variable transmitter circuit controlling the sound waves so emitted from the plurality of transducers to substantially minimize beats, cancellations, and reflections of the emitted sound waves within said predefined area; a receiver attachable to an item to be monitored; and an alarm coupled to the receiver, the receiver further being operative to actuate said alarm to provide an audible signal when the receiver no longer detects the inaudible sound waves. - View Dependent Claims (17, 18, 19, 20, 21, 22)
-
Specification