Capacitive Touch Gesture Recognition for Wet Environments

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing gesture recognition technologies in wireless headsets face issues such as inaccurate recognition of gestures like slide and long press, high assembly and cost requirements, and poor performance in wet conditions, where water or sweat can lead to false gesture detection.

Innovation Solution

A capacitive touch device with multiple sensors that samples capacitance values to determine touch states, accounting for interference caused by liquids, using thresholds and historical data to differentiate between touch and no touch states, thereby improving recognition accuracy and reducing hardware costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a capacitive sensing solution is used for gesture recognition, then the assembly process and structure space requirements are reduced, but the gesture recognition accuracy deteriorates when the headset is stained with water or sweat

Engineering Contradiction:
Improveassembly process and structure space requirementsVSAvoidgesture recognition accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The capacitance change is segmented into two components: interference capacitance (from water/sweat) and touch capacitance (from user touch). By separately identifying and subtracting the interference capacitance component based on its distinct temporal characteristics, the system isolates the genuine touch signal, thereby maintaining high recognition accuracy without additional hardware

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary detection and characterization of the interference capacitance caused by water or sweat before it causes false gesture recognition. By pre-identifying the interference signal pattern and subtracting it in advance, the system prevents false detection rather than correcting it afterward, improving accuracy while using only firmware processing

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If traditional capacitive sensing is used, then hardware costs are reduced, but false gesture detection occurs due to water or sweat interference

Engineering Contradiction:
Improvehardware costsVSAvoidgesture recognition reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The system continuously monitors capacitance changes over time and uses the temporal feedback pattern to distinguish between interference signals (water/sweat causing gradual or sustained capacitance change) and genuine touch signals (sudden, brief capacitance change). This feedback-based discrimination maintains reliability without additional hardware sensors

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The processing module acts as an intermediary between the capacitive sensor and gesture recognition system. It introduces a signal processing layer that mediates the raw capacitance data, filtering out interference components through algorithmic analysis and presenting only validated touch signals to the gesture recognition logic, thereby ensuring reliability with existing hardware

Inventive Principle:
Principle #24Intermediary (Mediator)

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 gesture recognition accuracy across various conditions, including wet environments, while maintaining low comprehensive costs and compatibility through firmware upgrades without additional hardware.

Implementation Method 1

a capacitance value sampled from the capacitive sensor in the capacitive touch device at the current sampling frame is taken to determine a touch state of the capacitive sensor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3936986B1Capacitive touch device and gesture recognition method thereof
Publication Date: 2024.10.30 SHENZHEN GOODIX TECH CO LTD
  • EP3936986B1 patent drawingFigure 1
  • EP3936986B1 patent drawingFigure 2
  • EP3936986B1 patent drawingFigure 3~4

AI summary

A capacitive touch device and a gesture recognition method thereof, a chip and a storage medium, the gesture recognition method includes: sample a capacitance of a capacitive sensor in the capacitive touch device to acquire a capacitance sampling value corresponding to a current sampling frame of the capacitive sensor (101); determine a first capacitance value of an interference capacitance caused by a liquid on the capacitive sensor according to the capacitance sampling value and reference information (102) corresponding to the current sampling frame; determining a touch state of the capacitive sensor represented by the current sampling frame according to the capacitance sampling value and the first capacitance value of the interference capacitance (103) corresponding to the current sampling frame; and recognizing a gesture of a user on the capacitive touch device according to timing information of the touch state of the capacitive sensor represented by the current sampling frame and a historical touch state of the capacitive sensor (104), which is beneficial to improving the accuracy of gesture recognition.