Capacitance Sensor Array for Obscured Feature Detection

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Solution Overview

Problem

Existing methods for detecting obscured features behind opaque surfaces, such as beams and studs, are inaccurate and require movement across the surface, often relying on metallic fasteners or edge detection, which limits their effectiveness in locating features without damaging the surface.

Innovation Solution

A capacitance-based detector with multiple sensor plates and a pattern matching module that compares measured capacitance readings to predetermined patterns to identify the location and width of obscured features, allowing for simultaneous detection of multiple features without moving the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional capacitive sensors are used to detect obscured features, then detection capability is provided, but the device requires movement across the surface and can only locate one feature at a time

Engineering Contradiction:
Improvedetection operationVSAvoiddetection speed
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The detector is divided into multiple sensor plates arranged in an array, where each sensor plate independently detects capacitance changes in its respective region. This segmentation enables simultaneous detection of multiple features across different locations without requiring device movement, directly resolving the contradiction between ease of operation and productivity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If magnetic detectors are used to find obscured support elements, then detection is possible, but the detector fails when no metallic fasteners are present

Engineering Contradiction:
Improvedetection reliabilityVSAvoiddetection capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces magnetic detection (which relies on metallic fasteners) with capacitive sensing that detects dielectric constant changes in the material itself. This substitution eliminates the dependency on metallic fasteners, providing reliable detection regardless of fastener presence while maintaining adaptability to various support elements like wood studs and metal beams.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If capacitive sensors detect edge of a feature, then feature location can be determined, but additional comparison circuitry is required and center point detection is difficult

Engineering Contradiction:
Improvefeature location precisionVSAvoidcircuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from edge-detection-based methods to a multi-point simultaneous measurement approach. By arranging multiple sensor plates across the detection surface and measuring capacitance values at multiple positions simultaneously, the system can directly identify feature center points and dimensions through pattern recognition, eliminating the need for complex comparison circuits and edge-detection algorithms.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides accurate and simultaneous detection of obscured features, including their width, without the need for movement, improving accuracy and ease of use by activating indicators to indicate feature locations directly on the surface.

Implementation Method 1

each having a capacitance that varies based on: (a) the proximity of the sensor plate to one or more surrounding objects, and (b) the dielectric constant(s) of the surrounding object(s)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

the dielectric constant(s) of the surrounding object(s)

Methodology Applied
Scientific EffectDielectric: Dielectric

Data Source

PatentEP2542921B2Obscured feature detector
Publication Date: 2019.04.03 DORROUGH DAVID M
  • EP2542921B2 patent drawingFigure 1
  • EP2542921B2 patent drawingFigure 2
  • EP2542921B2 patent drawingFigure 3

AI summary

A surface - conforming obscured feature (95) detector (10) includes a plurality of sensor plates (12, 13), each having a capacitance that varies based on the dielectric constant of the materials that compose the surrounding objects and the proximity of those objects. A sensing circuit is coupled to the sensor plates (12, 13) to measure the capacitances of the sensor plates. A controller is coupled to the sensing circuit to analyze the capacitances measured by the sensing circuit. One or a plurality of indicators (52) are coupled to the controller, and are selectively activated to identify the location of an obscured feature (95) behind a surface.