Security system with variable inductance sensor
First Claim
1. A security system for monitoring a premises having at least one portal, comprising:
- a proximity sensor mounted on a first portion of said portal;
an target mounted on a second portion of said portal and inductively coupled to said proximity sensor, said target elongated between first and second ends and having an inductively detectable feature varying along outer portions of said target between said first and second ends, said proximity sensor and said target movable relative to one another with said proximity sensor adjacent to and moving along said outer portions of said target between said first and second ends in response to relative motion of said first and second portions of said portal, the relative positions of said proximity sensor and each portion of said target between said first and second ends defining an inductance;
an alarm unit; and
a controller connected to said proximity sensor and said alarm unit for detecting a change in said inductance and activating said alarm unit in response thereto.
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Accused Products
Abstract
A security system that includes an inductive sensor commonly known as a "proximity sensor" or "variable reluctance sensor", an alarm unit, and a controller that allows a user to position the movable structure on which the sensor is mounted, e.g., a door or window, at a selected position and then arm the security system with the structure in that position to detect movement of the structure away from the selected position. For example, the user may open a window on which the sensor is mounted and then arm the alarm to trigger upon detection of movement of the window from that position or, alternatively, only upon detection of further opening of the window or, alternatively, only upon detection of closing of the window. A user could thus open a window a small, selected amount to admit fresh air without triggering the security system or open a door a small, selected amount to receive a caller or allow pets to enter or leave the premises without triggering the security system.
85 Citations
35 Claims
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1. A security system for monitoring a premises having at least one portal, comprising:
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a proximity sensor mounted on a first portion of said portal; an target mounted on a second portion of said portal and inductively coupled to said proximity sensor, said target elongated between first and second ends and having an inductively detectable feature varying along outer portions of said target between said first and second ends, said proximity sensor and said target movable relative to one another with said proximity sensor adjacent to and moving along said outer portions of said target between said first and second ends in response to relative motion of said first and second portions of said portal, the relative positions of said proximity sensor and each portion of said target between said first and second ends defining an inductance; an alarm unit; and a controller connected to said proximity sensor and said alarm unit for detecting a change in said inductance and activating said alarm unit in response thereto. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for using a security system for monitoring a premises having at least one portal, comprising the steps of:
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mounting a proximity sensor on a first portion of said portal; mounting a target on a second portion of said portal in inductive communication with said proximity sensor, said target elongated between first and second ends and having an inductively detectable feature varying along outer portions of said target between said first and second ends, said proximity sensor and said target movable relative to one another with said proximity sensor adjacent to and moving along said outer portions of said target between said first and second ends in response to relative motion of said first and second portions of said portal, the relative positions of said proximity sensor and each portion of said target between said first and second ends defining an inductance; providing an alarm unit; and providing a controller connected to said proximity sensor and said alarm unit; arming said security system; monitoring said inductance by said controller; activating said alarm unit in response to a change in said inductance. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35)
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Specification