Wrist-Worn Piezoelectric Sensor for Contactless Gesture Control

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Solution Overview

Problem

Current human-computer interface technologies require physical contact or buttons, and there is a need for a contactless method to control electronic devices using biometric signals such as muscular contractions and vibrations.

Innovation Solution

A wrist-worn sensor system utilizing an array of cantilever piezoelectric sensors to detect tendon movements, converting these signals into electrical currents, and processing them to identify specific finger gestures for sending commands to computing devices without physical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional button-based interfaces or touchscreen interfaces are used, then physical contact is required for device control, but this limits the intuitiveness and universality of the interface

Engineering Contradiction:
Improvecontactless control capabilityVSAvoidsensor array and signal processing system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces mechanical contact-based interfaces (buttons, touchscreens) with a biomechanical sensing system that detects tendon movements and muscle contractions. The piezoelectric sensors convert mechanical forces from finger movements into electrical signals, enabling contactless control while maintaining intuitive operation through natural body gestures.

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

Solution Approach 2:

The patent introduces an intermediary sensing system consisting of piezoelectric sensors and signal processing algorithms that translate natural finger movements into device control commands. This intermediary layer bridges the gap between physical gestures and digital interface responses, enabling contactless control without requiring direct physical contact with device buttons or screens.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If an array of piezoelectric sensors is used to detect tendon movements, then contactless finger gesture recognition is enabled, but the device structure becomes more complex

Engineering Contradiction:
Improvefinger gesture detection capabilityVSAvoidsensor array configuration and signal processing module
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the sensing function into multiple independent piezoelectric sensors arranged in an array, with each sensor detecting forces at specific locations. This segmentation enables precise localization of finger movements and differentiation between various gestures. The signal processing module further segments the analysis by evaluating force patterns, directions, and sequences to identify specific gestures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal gesture recognition system that can detect and interpret multiple types of finger movements (tapping, sliding, pinching, gripping) using the same sensor array and processing algorithms. The system is designed to accommodate various gesture types and can be adapted to different control applications, providing multi-functional capability without requiring separate detection mechanisms for each gesture type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If multiple piezoelectric sensors are arranged in an array, then measurement precision of finger gestures is improved, but the device becomes more complex

Engineering Contradiction:
Improvefinger gesture identification accuracyVSAvoidnumber of sensors and processing requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by positioning piezoelectric sensors at specific locations where they can detect forces from particular tendons or muscle groups. Each sensor is strategically placed to monitor specific anatomical regions, allowing the system to identify which fingers are moving and in what direction. This localized sensing approach improves measurement precision without requiring sensors throughout the entire device surface.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent enhances measurement precision by analyzing forces in multiple dimensions - not only the magnitude of force but also the direction and spatial distribution across the sensor array. The system evaluates the vector components of tendon forces and the temporal sequence of activations, adding dimensional information that improves gesture identification accuracy beyond simple force magnitude detection.

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

Enables users to control electronic devices with precise finger movements, providing a contactless and intuitive interface that allows for universal input mechanisms, reducing the need for physical interaction with devices.

Implementation Method 1

one or more piezoelectric sensors, wherein the one or more piezoelectric sensors emit electric currents generated upon pressure from wrist tendons on the one or more piezoelectric sensors

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3411772B1Wearable controller for wrist
Publication Date: 2021.10.06 FLICKTEK LTD
  • EP3411772B1 patent drawingFigure 1
  • EP3411772B1 patent drawingFigure 2
  • EP3411772B1 patent drawingFigure 3

AI summary

The present invention relates to wearable devices. A wrist-worn sensor for measuring wrist tendon forces corresponding to specific finger motions is provided, the sensor comprising: one or more piezoelectric sensors, wherein the one or more piezoelectric sensors emit electric currents generated upon pressure from wrist tendons on the one or more piezoelectric sensors; and a processing module configured for converting the electric currents generated upon pressure from wrist tendons into signals and for processing the signals for identification of one or more specific finger motions. A method for detecting specific finger movements based on wrist-tendon forces is also provided.