Sensor for count and tamper detection
First Claim
1. In a meter having a spatially varying magnetic field, the spatially varying magnetic field varying with respect to source and being related to a count of usage of a metered product, a sensor for sensing count and tamper, comprising:
- a count sensor disposed proximate the source of the spatially varying magnetic field for the detection of gradiations of the spatially varying magnetic field, said count sensor being substantially unaffected by a static magnetic field over a certain range of field strength; and
a tamper sensor disposed proximate the count sensor within the spatially varying magnetic field for the detection of a tampering static magnetic field applied external to the meter.
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Accused Products
Abstract
A sensor assembly and method of forming the sensor assembly for sensing count and tamper, where the count is related to an energy field having a gradient along an axis of sensitivity and where the tamper is related to a static energy field and where the energy comprising the static energy field is the same type as the energy comprising the energy field having a gradient, includes an energy gradient detector that has at least a first sensor spaced apart from and communicably coupled to a second sensor along the axis of sensitivity. A static energy detector that has at least a first shielded sensor, the shielded sensor being substantially shielded from the energy field having a gradient and from the static energy field. A second unshielded sensor is communicably coupled to the shielded sensor. The invention further includes a method of detecting a spatially varying magnetic field.
54 Citations
30 Claims
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1. In a meter having a spatially varying magnetic field, the spatially varying magnetic field varying with respect to source and being related to a count of usage of a metered product, a sensor for sensing count and tamper, comprising:
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a count sensor disposed proximate the source of the spatially varying magnetic field for the detection of gradiations of the spatially varying magnetic field, said count sensor being substantially unaffected by a static magnetic field over a certain range of field strength; and a tamper sensor disposed proximate the count sensor within the spatially varying magnetic field for the detection of a tampering static magnetic field applied external to the meter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 24)
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18. A method of detecting a spatially varying magnetic field in a meter, the meter for metering a commodity consumption, the spatially varying magnetic field having an origin and varying about an axis, the axis being displaced from the origin of the spatially varying magnetic field, comprising the steps of:
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disposing a gradiometer type sensor spaced apart from and proximate the origin of the spatially varying magnetic field, the sensor having a sensitivity axis ,the sensitivity axis being substantially normal to plane of variation of the spatially varying magnetic field, such that the sensor senses a magnetic field gradient, said magnetic field gradient being related to the commodity consumption; and disposing a magnetometer type sensor proximate the gradiometer type sensor to sense the presence of an externally applied static magnetic field, said static field being imposed to tamper with the sensing of the commodity consumption. - View Dependent Claims (19, 20, 21, 22, 23)
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- 25. water.
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26. A sensor assembly for sensing count and tamper, said count being related to an energy field having a gradient along an axis of sensitivity and said tamper being related to a static energy field where the energy comprising the static energy field is the same type as the energy comprising the energy field having a gradient, the sensor assembly comprising:
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an energy gradient detector having at least a first sensor spaced apart from and communicably coupled to a second sensor along the axis of sensitivity; and a static energy detector having at least a first shielded sensor, the shielded sensor being substantially shielded from the energy field having a gradient and from the static energy field, and a second unshielded sensor being communicably coupled to said shielded sensor. - View Dependent Claims (28)
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30. A method of forming a sensor assembly for sensing count and tamper, said count being related to an energy field having a gradient along an axis of sensitivity and said tamper being related to a static energy field where the energy comprising the static energy field is the same type as the energy comprising the energy field having a gradient, the method comprising the steps of:
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providing a substrate; forming a first count sensor for sensing count on said substrate; forming a second count sensor for sensing count on said substrate, said second count sensor being spaced apart from said first count; forming a communication path communicatively coupling said first count sensor to said second count sensor; forming a first tamper sensor for sensing tamper on said substrate, said first tamper sensor being disposed centered with respect to said first and said second count sensors; forming a shield over said first tamper sensor for shielding said first tamper sensor from the energy field; forming a second tamper sensor for sensing tamper on said substrate; and forming a communication path communicatively coupling said first tamper sensor to said second tamper sensor.
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Specification