ANR Headphone Tap Detection via Current Sensing

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Solution Overview

Problem

Conventional acoustic noise reduction (ANR) headphones lack the ability to distinguish between acoustic noise and user-initiated pressure changes, such as taps, which can lead to incorrect interpretations of user inputs and inefficient control of audio system functions.

Innovation Solution

The implementation of a method that senses current changes in the ANR module responsive to pressure changes in the ear canal, using a current sensor and processor to determine peak values and adapt a threshold for detecting taps, allowing for reliable control of audio system modes and attributes without physical buttons.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional ANR headphones use pressure sensing to detect user inputs, then user control capability is improved, but the system cannot distinguish between acoustic noise and intentional taps leading to false detections

Engineering Contradiction:
Improveuser control capabilityVSAvoiddetection accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent segments the pressure detection function into two independent sensing paths: a first pressure sensor dedicated to detecting user taps on the headphone exterior, and a second pressure sensor (microphone) for detecting acoustic noise within the ear canal. This segmentation allows the control system to distinguish between intentional user inputs and environmental acoustic disturbances, resolving the false detection problem while maintaining ease of operation.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If ANR headphones eliminate physical buttons for control, then device simplicity and aesthetics are improved, but reliable tap detection becomes more difficult

Engineering Contradiction:
Improvecontrol interface simplicityVSAvoidtap detection reliability
Core Design Contradiction:
Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces the traditional mechanical button interface with an electronic tap detection system. A first pressure sensor mounted on the headphone exterior detects mechanical tap forces, converting them into electrical signals for digital processing. This substitution eliminates physical buttons while providing reliable tap detection through electronic sensing and signal processing, including filtering and threshold comparison mechanisms.

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

3Speed

If the system uses a fixed threshold for tap detection, then detection speed is improved, but adaptability to different users and environments is reduced

Engineering Contradiction:
Improvedetection speedVSAvoidthreshold adaptability
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic threshold adjustment mechanism where the tap detection threshold is not fixed but adapts based on environmental conditions and usage patterns. The system continuously monitors pressure sensor outputs and adjusts the detection threshold accordingly, allowing faster response to genuine taps while filtering out ambient noise. This dynamic adaptation maintains high detection speed while improving versatility across different users and environments.

Inventive Principle:
Principle #15Dynamics

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 reliable detection of user taps to change audio system modes and attributes, improving user interaction by avoiding misinterpretation of noise as user inputs and eliminating the need for cumbersome control buttons.

Implementation Method 1

tapping at least one of a headphone worn by a user, an ear of the user, and the head of the user to cause an acoustic pressure change in an ear canal of the user

Methodology Applied
Scientific EffectPressure change detection:

Data Source

PatentEP3662465B1Method of controlling an acoustic noise reduction audio system by user taps
Publication Date: 2021.07.07 BOSE CORP
  • EP3662465B1 patent drawingFigure 1
  • EP3662465B1 patent drawingFigure 2
  • EP3662465B1 patent drawingFigure 3

AI summary

Described are a headphone and a method for controlling an audio system. The method includes tapping a headphone or head of a user to cause an acoustic pressure change in an ear canal of the user wherein the ear canal is sealed by an acoustic noise reduction (ANR) headphone having an ANR module. A current provided to the ANR module is sensed and used to determine if a tap or a dual tap occurred. A mode of operation of the audio system or an attribute of an audio input signal may be changed in response to the determination of an occurrence of a tap or a dual tap.