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SENSING SYSTEM AND METHOD FOR SECURITY SYSTEMS

IP.com Disclosure Number: IPCOM000196969D
Publication Date: 2010-Jun-22
Document File: 6 page(s) / 93K

Publishing Venue

The IP.com Prior Art Database

Abstract

A differential, self-calibrating, low-power capacitive sensing method for security applications is disclosed. The sensing method described herein, determines the door opening and racking in various security system applications such as, in cargo containers and the like. The sensing method senses air gap between the door frame and wall of the container when the door is opened or closed. The air gap is sensed by using a capacitance to flag an intrusion.

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Page 1 of 6

RP13424

SENSING SYSTEM AND METHOD FOR SECURITY SYSTEMS

BRIEF ABSTRACT

    A differential, self-calibrating, low-power capacitive sensing method for security applications is disclosed. The sensing method described herein, determines the door opening and racking in various security system applications such as, in cargo containers and the like. The sensing method senses air gap between the door frame and wall of the container when the door is opened or closed. The air gap is sensed by using a capacitance to flag an intrusion.

KEYWORDS

    Self-calibrating, capacitance, security, cargo container(s), air gap, door frame, multiple capacitance(s), bi-level capacitance, multiple sensor node(s), Digital to Analog converter, DAC, phase difference, false alarms and false positives.

DETAILED DESCRIPTION

    Determining door opening and racking in security system applications such as, cargo containers has been a major challenge. Typical challenges faced by conventional sensor units are employed to trace the door opening and racking include sensor detection period (long periods), cost of the sensing system, reliability and an increase in false positives as the sensor degrades with time.

    Conventional security systems employ magnetic sensing system. However, the magnetic sensing system has an inherent problem of long term drifts. The long term drifts result in loss of accuracy and hence pose a reliability issue.

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RP13424

    Therefore there exists a need for a sensing system and method that offers low cost, increased reliability with reduced false positives.

    A sensing system that provides low cost sensing method for security system applications is disclosed. The sensing system is used in security systems applications for determining the door opening and racking in cargo containers. The sensing method is differential, self-calibrating and low-power capacitive.

    Figure 1, illustrates the sensing system. The sensing system leverages ratio metric bi-level capacitance sensing technology to the area of security systems. The present sensing system senses air gap between the door frame and wall of the container when the door is opened or closed.

    Sensing the air gap is enabled by using a capacitance to flag an intrusion. The sensing method also offers to use multiple capacitance sensing elements in close proximity to each other on a substrate material. Thereby, multiple sen...