Ratiometric stud sensing
AssigneeZircon Corporation
InventorLawrence F. Miller
Life of this patent
Estimating the term…
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.
Claims37
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;
- providing an indication of the ratio, and wherein if the indication is approximately one, thereby locating a centerline of the feature.
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;
- computing a ratio of the first and second capacitances;
- determining whether one or more of the first and second capacitances exceeds a threshold;
- and
- re-measuring the first and second capacitances if one or more of the first and second capacitances exceeds the threshold.
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;
- computing a ratio of the first and second capacitances;
- determining whether the ratio is within a predetermined range;
- and
- wherein the predetermined range has fixed boundaries.
A sensor for finding a feature of a structure, comprising:
- 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;
- an indicator coupled to the comparison circuit thereby to provide an indication of the ratio of the capacitances;
- wherein if the indication is that the ratio is approximately one, thereby locating a centerline of the structure.
A sensor for finding a feature of a structure, comprising:
- 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 with respect to a constant reference capacitance;
- a second measurement circuit coupled to the second plate, the second measurement circuit measuring a second capacitance value of the second capacitor with respect to the constant reference capacitance;
- 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;
- wherein the processing circuit determines whether the ratio is within a predetermined range which has fixed boundaries.
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;
- computing a ratio of the first and second capacitance;
- determining whether the ratio is within a predetermined range of approximately between 0.32 and 0.45;
- and
- indicating if the ratio is within the predetermined range that an edge of the feature is detected.
A sensor for finding a feature of a structure, comprising:
- 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;
- and
- an indicator coupled to the comparison circuit thereby to provide an indication of the ratio of the capacitances;
- wherein if the indication is that the ratio is in the range of approximately 0.32 to 0.45, thereby locating an edge of the structure.
Dependencies are inferred from the claim text.