Capacitive Input Mat for Foot Position Tracking

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Solution Overview

Problem

Conventional dance pads do not track the proximity or position of a user's feet, limiting the accuracy and interaction in dance-based video games.

Innovation Solution

A capacitive interface system using probes and a conductive pattern on a mat, where the probe sensor on the user's foot detects changes in capacitance to determine its position through triangulation, allowing precise tracking of foot motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional dance pads with pushbuttons are used, then the device structure is simple and easy to manufacture, but the position tracking precision and measurement accuracy are insufficient

Engineering Contradiction:
Improvefoot position tracking precisionVSAvoidcapacitive interface system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical pushbutton system with a capacitive sensing system. Instead of detecting physical button presses, the system uses capacitive sensors to detect changes in capacitance caused by the proximity of the user's feet, thereby substituting mechanical detection with electrical field-based detection to achieve non-contact position tracking.

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

Solution Approach 2:

The patent introduces an intermediary capacitive field between the user's feet and the sensors. The capacitive field acts as a mediator that transmits information about foot position without requiring direct physical contact, enabling precise position tracking while maintaining system simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If capacitive sensors with conductive pattern are implemented, then the position tracking accuracy and resolution are improved, but the manufacturing complexity and device cost increase

Engineering Contradiction:
Improvefoot position detection accuracyVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent divides the sensing surface into multiple discrete capacitive sensors arranged in a conductive pattern. Each sensor independently measures capacitance changes, and the collective data from segmented sensors enables precise position determination through triangulation or comparative analysis, thereby achieving high manufacturing precision through modular segmentation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes changes in capacitance parameters caused by the proximity of the user's feet to different conductive regions. By measuring and analyzing these capacitance parameter variations across multiple sensors, the system determines foot position with high accuracy, transforming a simple capacitive measurement into a sophisticated position detection method.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If probe sensor worn on user's foot is used, then the proximity detection capability is enhanced, but the ease of operation and user comfort may be reduced

Engineering Contradiction:
Improveproximity detection accuracyVSAvoiduser operation convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The probe sensor worn on the user's foot serves itself by utilizing the user's natural body movements and proximity to the mat. The sensor automatically detects position information through capacitive coupling without requiring active user input or adjustment, making the system easy to operate while maintaining high measurement precision.

Inventive Principle:
Principle #25Self-service

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

Enhances the resolution and accuracy of foot position tracking, enabling more precise input detection and allowing for velocity and acceleration calculations, improving user interaction in dance games and potentially other applications.

Implementation Method 1

The capacitance of the capacitor is defined as the ratio of the magnitude of the charge on either plate to the voltage between the plates. In general, the capacitance is directly proportional to the area of the plates and the dielectric constant of the material between the plates. The capacitance is inversely proportional to the distance between the plates.

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

When a voltage is applied between the first and second conductive plates, charges of opposite polarity build up on the plates and establish an electric field. Most of the electric field is concentrated in the space between the two plates. However, for plates of finite size some electric field leaks out at the edges as indicated by the curved field lines.

Methodology Applied
Scientific EffectElectric Field: Electric Field

Implementation Method 3

Embodiments of the present invention utilize the concept of capacitive coupling, which is based on the electrical property of 'capacitance'. Capacitive coupling can be said to exist between two conductive surfaces that are in sufficiently close proximity with a dielectric material between them or sufficiently close to them.

Methodology Applied
Scientific EffectCapacitive coupling:

Data Source

PatentEP2392988B8Capacitive input for computer entertainment device
Publication Date: 2017.08.16 SONY INTERACTIVE ENTERTAINMENT LLC

AI summary

A capacitive input apparatus and method are disclosed. The apparatus includes a mat and a probe. The mat has a dielectric layer sandwiched between a common conductive layer and a patterned conductive layer having a grid pattern containing plural conductive regions. Each conductive region is selectively coupled to a corresponding capacitance sensor that is responsive to a signal capacitively coupled to a corresponding one of the conductive regions. The probe can be worn on a user's feet and can change a capacitive coupling of the signal. A degree of the change of the signal varies with a degree of proximity of the probe to the corresponding one of the conductive regions. In the method, a capacitive coupling of the signal can be changed with the probe. Measurements collected from the capacitance sensor can provide input to a computer program based on values of one or more measurements.