Systems, methods, and apparatus for detecting ferromagnetic foreign objects in a predetermined space
First Claim
1. An apparatus for detecting an object, comprising:
- a sense coil configured to receive a voltage signal from a signal generator; and
a processor configured to;
determine an amount of change in a reactance measured at a sense frequency fs, of the sense coil from a previous reactance value previously measured at the sense frequency fs for the sense coil,determine an amount of change in a resistance of the sense coil from a previous resistance value for the sense coil,perform a trigonometric operation on a ratio of the amount of change in the reactance of the sense coil to the amount of change in the resistance of the sense coil,determine a type of the object based on a result of the trigonometric operation falling within a predetermined range of values corresponding to the type of the object and determine a presence of the object based on the trigonometric operation.
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Accused Products
Abstract
One aspect of the disclosure provides apparatus for detecting an object. The apparatus comprises a sense coil. The apparatus comprises a processor configured to determine an amount of change in a reactance of the sense coil from a previous reactance value for the sense coil. The processor is configured to determine an amount of change in a resistance of the sense coil from a previous resistance value for the sense coil. The processor is configured to determine a presence of the object based on a relationship between the amount of change in the reactance of the sense coil and the amount of change in the resistance of the sense coil. The processor performs an inverse tangent operation on a quotient of the amount of change in the reactance of the sense coil divided by the amount of change in the resistance of the sense coil.
50 Citations
12 Claims
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1. An apparatus for detecting an object, comprising:
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a sense coil configured to receive a voltage signal from a signal generator; and a processor configured to; determine an amount of change in a reactance measured at a sense frequency fs, of the sense coil from a previous reactance value previously measured at the sense frequency fs for the sense coil, determine an amount of change in a resistance of the sense coil from a previous resistance value for the sense coil, perform a trigonometric operation on a ratio of the amount of change in the reactance of the sense coil to the amount of change in the resistance of the sense coil, determine a type of the object based on a result of the trigonometric operation falling within a predetermined range of values corresponding to the type of the object and determine a presence of the object based on the trigonometric operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for detecting an object, comprising:
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means for sensing an object configured to receive a voltage signal from a signal generator; means for determining an amount of change in a reactance measured at a sense frequency fs of the means for sensing the object from a previous reactance value previously measured at the sense frequency fs for the means for sensing the object, means for determining an amount of change in a resistance of the means for sensing the object from a previous resistance value for the means for sensing the object, means for performing a trigonometric operation on a ratio of the amount of change in the reactance of the means for sensing the object to the amount of change in the resistance of the means for sensing the object; means for determining a type of the object based on a result of the trigonometric operation falling within a predetermined range of values corresponding to the type of the object; and means for determining a presence of the object based the trigonometric operation. - View Dependent Claims (10, 11, 12)
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Specification