Speaker-as-Microphone Switching for Low-Power Mobile Audio
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Solution Overview
Problem
Capacitive microphones in mobile devices consume significant power, limit audio performance, especially for high-volume sounds, and increase device cost when dual microphones are used to address these issues.
Innovation Solution
A mobile device design that utilizes a speaker as a microphone, with a controller processing signals from both speakers to determine sound characteristics and select the appropriate speaker for sound reception or emission based on volume and frequency, allowing for efficient power use and improved audio performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If capacitive microphones are used in mobile devices, then audio signal reception is enabled, but power consumption increases significantly
Solution Approach 1:
The speaker is designed to perform dual functions: serving as both a sound output device and a sound input device (microphone). The same speaker component can be switched between generating sound waves and detecting incident sound waves, eliminating the need for separate dedicated microphone hardware and reducing overall power consumption while maintaining audio reception capability
Solution Approach 2:
The speaker serves its own additional function by detecting sound waves incident upon it. The speaker's existing structure and components are utilized for both sound generation and sound detection, allowing the device to self-monitor ambient audio without requiring separate dedicated microphone components
2Reliability
If capacitive microphones are used for high-volume sounds, then audio performance is limited, but adapting amplifier circuitry increases power consumption and cost
Solution Approach 1:
The speaker handles both low-volume and high-volume sound detection using its inherent capability to detect incident sound waves across a wide dynamic range. The speaker's robust structure and wide frequency response allow it to capture loud sounds (such as rock concerts) without requiring specialized high-volume microphone components or additional amplifier circuitry
Solution Approach 2:
The system changes the operational parameters of the speaker by switching between sound generation mode and sound detection mode. When detecting sound, the speaker operates in a passive detection mode where incident sound waves induce electrical signals directly, allowing high-volume sound capture without the need for active amplification circuitry that would increase power consumption
3Reliability
If dual capacitive microphones are used for low-volume and high-volume sounds, then audio performance is improved, but device cost increases
Solution Approach 1:
The speaker serves multiple audio functions including sound output, low-volume sound detection, and high-volume sound detection. This single component replaces what would traditionally require multiple separate microphone components, simplifying the device architecture while maintaining comprehensive audio performance across different volume ranges
Solution Approach 2:
The sound generation and sound detection functions are merged into a single speaker component. The speaker's ability to both generate sound waves and detect incident sound waves combines multiple audio functions into one unified component, reducing the total number of parts and simplifying device complexity
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
This approach reduces power consumption, enhances audio performance by utilizing speakers as microphones for high-volume sounds, and maintains cost-effectiveness by eliminating the need for dual microphones.
Implementation Method 1
a speaker associated with the enclosure for generating sound
Implementation Method 2
receive a signal from the speaker, the signal induced at least in part by sound incident on the speaker
Data Source
AI summary
In accordance with methods and systems of the present disclosure, a mobile device may include an enclosure adapted such that the enclosure is readily transported by a user of the mobile device, a speaker associated with the enclosure for generating sound, and a controller within the enclosure, communicatively coupled to the speaker. The controller may be configured to receive a signal from the speaker, the signal induced at least in part by sound incident on the speaker other than sound generated by the speaker and process the signal.