Key Position Detection Using Segmented Drive Coils
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Solution Overview
Problem
Existing techniques for detecting the position of multiple movable members, such as keys in a keyboard musical instrument, face challenges in achieving high accuracy due to interference from magnetic fields generated by adjacent members.
Innovation Solution
A detection system comprising a first and second detectable coil on each movable member, paired with a first and second signal generator that include drive coils with specific current flow directions, allowing for the generation of detection signals based on distance without significant magnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single drive coil is used for each key, then the device complexity is reduced, but magnetic field interference between adjacent keys increases
Solution Approach 1:
The drive coil for each key is divided into two separate coils (first drive coil and second drive coil) that are activated alternately. This segmentation allows the magnetic field from one key to be confined to its own detectable coil, preventing interference with adjacent keys while maintaining simple overall device structure.
Solution Approach 2:
Each key is equipped with its own dedicated detectable coil positioned to detect only the magnetic field from its corresponding drive coil. This local quality assignment ensures that magnetic interference from adjacent keys does not affect the detection accuracy of each individual key's position.
2Adaptability or versatility
If multiple movable members are placed in close proximity, then the keyboard layout is optimized, but magnetic field interference between adjacent members increases
Solution Approach 1:
The detection system is segmented into independent key pairs, each with its own drive coil and detectable coil. This segmentation creates isolated detection zones that prevent magnetic field interference between closely spaced adjacent keys, allowing optimized keyboard layout without detection accuracy degradation.
Solution Approach 2:
The drive coils are activated in alternating periodic cycles, where only one drive coil is active at a time. This periodic action ensures that magnetic fields are generated sequentially rather than simultaneously, eliminating interference between adjacent keys while maintaining close spacing for layout optimization.
3Measurement precision
If drive coils and detectable coils are positioned close together, then the detection sensitivity is improved, but magnetic field interference from adjacent keys increases
Solution Approach 1:
The system uses separate drive coils and detectable coils positioned close together for each key, with the drive coil segmented into two parts that activate alternately. This segmentation allows high detection sensitivity through close positioning while preventing magnetic field interference by ensuring only one coil pair is active at a time.
Solution Approach 2:
The alternating periodic activation of drive coils ensures that magnetic fields are generated sequentially, allowing detectable coils to be positioned close to their corresponding drive coils for high sensitivity without being affected by simultaneous magnetic interference from adjacent keys.
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
The system enables high-accuracy detection of the position of each movable member by minimizing magnetic field interference, thereby enhancing the precision of key detection in musical instruments and similar configurations.
Implementation Method 1
a first drive coil that faces the first detectable coil, configured to generate a first detection signal based on a distance between the first detectable coil and the first drive coil
Implementation Method 2
the first detectable coil includes a first portion and a second portion where induced currents in directions opposite to each other are generated by electromagnetic induction of the first drive coil
Data Source
AI summary
A first detection signal is generated based on a distance between a first detectable coil disposed on a first key and a first drive coil. A second detection signal is generated based on a distance between a second detectable coil disposed on a second key and a second drive coil. The first drive coil includes first and second drivers through which current flows in a first direction and in a second direction opposite to the first direction, respectively. The second drive coil includes third and fourth drivers through which current flows in the first direction. The first detectable coil includes first and second portions in which induction currents in opposite directions are generated by electromagnetic induction of the first drive coil. The second detectable coil includes third and fourth portions in which induction currents in the same direction are generated by electromagnetic induction of the second drive coil.