Acoustic Joint Angle Sensing Using Speaker Microphone Time Delay
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Solution Overview
Problem
Existing electronic devices that use hinges or joints for angular adjustment often rely on purpose-built sensors to determine the current joint angle, which occupy valuable space and provide limited information, typically only indicating if the angle is at or above zero.
Innovation Solution
An electronic device utilizing a speaker and microphone to emit and detect a known sound, measuring the transmission time to calculate the current joint angle based on known distances from the joint, allowing for precise angular adjustment determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If purpose-built sensors are used to determine joint angle, then angle measurement capability is provided, but device space is occupied and information detail is limited
Solution Approach 1:
The speaker and microphone are repurposed to perform angle measurement in addition to their primary audio functions. The speaker emits test tones while the microphone detects them, and the system calculates joint angle based on transmission time variations, allowing existing components to serve multiple purposes without adding dedicated sensors
Solution Approach 2:
The device uses its own built-in speaker and microphone to measure joint angle, eliminating the need for external or dedicated sensing components. The audio subsystem serves itself by providing angle measurement capability through its existing hardware resources
2Loss of information
If purpose-built sensors are used to determine joint angle, then angle information is provided, but information detail is limited to binary states
Solution Approach 1:
The mechanical sensor system is replaced with an acoustic measurement system. Instead of using physical sensors that provide limited binary feedback, the patent uses sound wave transmission time through air to continuously measure joint angle, providing detailed angular information without complex sensor hardware
3Volume of moving object
If speaker and microphone are used for angle sensing, then no additional space is occupied, but measurement precision must be maintained
Solution Approach 1:
The system emits periodic test tones from the speaker and measures the transmission time to the microphone at regular intervals. This periodic acoustic measurement allows continuous monitoring of joint angle changes while maintaining precision through repeated measurements and computational analysis of transmission time variations
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 method enables accurate determination of the joint angle without occupying additional space, providing detailed angular information, and can be applied to various electronic devices with moveable portions.
Implementation Method 1
An angle sensing machine is configured to emit a known sound from the speaker, detect the known sound at the microphone
Implementation Method 2
detect the known sound at the microphone, and measure a transmission time of the known sound from speaker to microphone
Data Source
AI summary
An electronic device includes a first portion, a second portion, and a joint moveably coupling the first and second portions for angular adjustment between the first and second portions. A speaker is fixed on the first portion at a first known distance from the joint, and a microphone is fixed on the second portion at a second known distance from the joint. An angle sensing machine is configured to emit a known sound from the speaker, detect the known sound at the microphone, and measure a transmission time of the known sound from speaker to microphone. Based on the transmission time, a current angle of the first portion relative to the second portion is calculated.