Ratiometric stud sensing
First Claim
1. A method of finding a feature behind a surface using a sensor having first and second plates, the method comprising the acts of:
- moving the sensor and surface adjacent one another;
measuring a first capacitance of a first capacitor including the first plate;
measuring a second capacitance of a second capacitor including the second plate; and
computing a ratio of the first and second capacitances.
1 Assignment
0 Petitions
Accused Products
Abstract
A stud or joist sensor device and associated sensing method using a ratio of capacitance measurements from a plurality of capacitive sensing elements. The device locates a feature of an object or discontinuity behind a surface or wall, such as an edge and/or a center of a stud behind the surface, a joist under a floorboard, a gap behind sheetrock, a metal conductor behind a surface or the like. The device may be moved over a surface, thereby detecting changes in capacitance. The change in capacitance is due to the effective dielectric constant caused by the passage over an object such as a stud. When two capacitive sensing elements provide equivalent capacitance measures, the device is over a centerline of the stud. When a ratio of the capacitance measurements equals a transition ratio, the device is over an edge of the stud.
78 Citations
39 Claims
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1. A method of finding a feature behind a surface using a sensor having first and second plates, the method comprising the acts of:
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moving the sensor and surface adjacent one another;
measuring a first capacitance of a first capacitor including the first plate;
measuring a second capacitance of a second capacitor including the second plate; and
computing a ratio of the first and second capacitances. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of finding a feature behind a surface using a sensor having first and a second plates of approximately equal areas, the method comprising the acts of:
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moving the sensor and surface adjacent one another;
measuring a first capacitance of a first capacitor including the first plate, measuring a second capacitance of a second capacitor including the second plate;
comparing the first and second capacitances; and
repeating the acts of measuring and comprising. - View Dependent Claims (22, 23, 24)
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25. A sensor for finding a feature of a structure comprising:
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a first plate having a first capacitance and adapted for forming a first capacitor with the structure;
a second plate having a second capacitance and adapted for forming a second capacitor with the structure;
a first measurement circuit coupled to the first plate, the first measurement circuit measuring a first capacitance value of the first capacitor;
a second measurement circuit coupled to the second plate, the second measurement circuit measuring a second capacitance value of the second capacitor; and
a comparison circuit coupled to the first and second measurement circuits, the comparison circuit generating a ratio of the first and second capacitance values. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A sensor comprising:
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a first and a second plate positioned in about the same plane and spaced apart, and adapted to be located adjacent a surface;
a measurement circuit coupled to the first and second plates thereby to measure a capacitance value of each of the plates; and
a comparison circuit coupled to receive the measured capacitance values and determine a ratio between a change in the measured capacitance values. - View Dependent Claims (37, 38, 39)
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Specification