Earphone In-Position Detection via Resonant Frequency Analysis
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Solution Overview
Problem
Existing earphone status detection methods, such as using capacitive sensors, increase hardware costs and complexity, necessitating a simpler and quicker detection method.
Innovation Solution
A terminal-based method involving a processor, earphone connector, and detection units to disable audio signal paths and detect electrical signals at specific audio output ends to determine the in-position state of earphones by analyzing low-frequency resonant frequency values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a built-in capacitive sensor is provided in the earphone to detect in-position state, then the detection accuracy is improved, but the hardware cost and circuit design complexity increase
Solution Approach 1:
The existing audio output terminals are made to serve dual purposes: both audio signal transmission and earphone status detection. By applying test signals through the same audio output terminals used for normal audio playback, the patent eliminates the need for separate detection hardware while maintaining detection functionality.
Solution Approach 2:
The earphone status detection is achieved by utilizing the earphone's own electrical characteristics (impedance, resonant frequency) during normal operation. The system detects status changes by monitoring variations in the electrical signals already present in the audio pathway, without requiring external or additional sensing components.
2Measurement precision
If a built-in capacitive sensor is provided in the earphone to detect in-position state, then the detection accuracy is improved, but the hardware cost increases
Solution Approach 1:
The existing audio output terminals are made to serve dual purposes: both audio signal transmission and earphone status detection. By applying test signals through the same audio output terminals used for normal audio playback, the patent eliminates the need for separate detection hardware while maintaining detection functionality.
Solution Approach 2:
Instead of using expensive dedicated capacitive sensors, the patent employs inexpensive test signal generation and analysis methods that utilize existing circuitry. The detection is achieved through software-based analysis of electrical characteristics rather than costly hardware additions.
3Measurement precision
If traditional capacitive sensor detection is used, then the in-position state can be detected, but the detection process consumes more power
Solution Approach 1:
The earphone status detection is performed periodically by injecting test signals at specific intervals rather than continuously monitoring. The processor sends test signals through the audio output terminals at defined moments and analyzes the returned electrical characteristics, reducing continuous power consumption while maintaining effective detection capability.
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 simple and quick detection of earphone status without additional hardware, reducing power consumption and complexity, and effectively determining whether earphones are in use.
Implementation Method 1
determining a first frequency value of a low-frequency resonant point of the first earphone according to the electrical signal of the first audio signal end and the electrical signal of the third audio signal end
Data Source
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AI summary
A method used by a terminal to detect an earphone status and a terminal are disclosed. The method includes: disabling, by a processor, a path for outputting an audio signal to a second earphone; detecting electrical signals of a first audio output end and a third audio output end of a first earphone; and determining a frequency value of a low-frequency resonant point of the first earphone according to the electrical signals of the first audio output end and the third audio output end, and determining, according to the frequency value of the low-frequency resonant point, whether the first earphone is in an in-position state. In this way, only the electrical signals of the first audio output end and the third audio output end need to be detected, and it may be determined, according to changes of the electrical signals, whether the earphone is in position. Therefore, a status of the first earphone can be simply and quickly detected.