Wearable Device Wear Detection Using Dual Transducer Signal Correlation

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Solution Overview

Problem

Wearable electronic devices continue to consume power unnecessarily when not being worn, as they lack an effective method to detect whether they are in use or not.

Innovation Solution

A method and device utilizing two transducers, such as microphones or accelerometers, to differentiate between ambient and body-conducted sound signals, generating correlation signals to determine if the device is being worn by comparing signal energies and correlations during voiced and unvoiced speech periods, with thresholds determining the device's wear status.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the device continues to operate without wear detection, then the device remains ready for immediate use, but unnecessary battery power is consumed when not being worn

Engineering Contradiction:
ImproveDevice readinessVSAvoidBattery power consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The device automatically detects its own wear status using onboard transducers and signal processing algorithms, eliminating the need for manual user input. The system monitors acoustic and vibration signals to determine whether it is being worn, and autonomously adjusts its operational state accordingly, enabling it to serve itself in wear detection and power management.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The device performs periodic wear detection by analyzing speech signals at specific intervals (e.g., during voiced and unvoiced speech periods). Instead of continuous monitoring, the system uses periodic correlation analysis between transducer signals to determine wear status, reducing overall power consumption while maintaining effective detection capability.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If wear detection is implemented using multiple transducers and signal processing, then accurate wear status determination is achieved, but device complexity increases

Engineering Contradiction:
ImproveWear detection accuracyVSAvoidSignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The wear detection process is segmented into distinct phases: voiced speech detection, unvoiced speech detection, and correlation analysis. Each phase processes specific signal characteristics separately, allowing the system to achieve high detection accuracy through structured analysis while managing complexity by breaking down the overall task into manageable segments with clear boundaries.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11533574B2Wear detection
Publication Date: 2022.12.20 CIRRUS LOGIC INC
  • US11533574B2 patent drawing
  • US11533574B2 patent drawing
  • US11533574B2 patent drawing

AI summary

A method is used for detecting whether a device is being worn, when the device comprises a first transducer and a second transducer. It is determined when a signal detected by at least one of the first and second transducers represents speech. It is then determined when said speech contains speech of a first acoustic class and speech of a second acoustic class. A first correlation signal is generated, representing a correlation between signals generated by the first and second transducers during at least one period when said speech contains speech of the first acoustic class. A second correlation signal is generated, representing a correlation between signals generated by the first and second transducers during at least one period when said speech contains speech of the second acoustic class. It is then determined from the first correlation signal and the second correlation signal whether the device is being worn.