Keyboard Key Displacement Sensing With Coil-Weight Detection
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Solution Overview
Problem
Existing musical keyboard instruments face challenges in accurately detecting slight displacements of keys due to limited changes in current flow through coils, resulting in inadequate detection signals.
Innovation Solution
The implementation of a musical keyboard instrument configuration featuring a signal generator with a coil and an adjustment weight, where the adjustment weight, made of a magnetic or conductive material, rotates relative to the coil, generating a detection signal with varying amplitude levels based on key displacement, utilizing a filter with a frequency response that changes with the distance between the load part and the coil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a coil and metal plate configuration is used to detect key displacement, then the structure is simple, but the detection precision is insufficient due to limited current change
Solution Approach 1:
The patent changes the physical parameters of the detection part by using a magnetic material with high permeability instead of a simple metal plate. This parameter change increases the magnetic flux variation when the key is depressed, thereby generating a larger current change in the coil and improving detection precision without complicating the overall structure.
Solution Approach 2:
The patent employs composite material construction by combining the coil with a magnetic material (having high permeability) to form an integrated detection part. This composite structure enhances the magnetic field interaction and flux change response to key displacement, achieving better measurement precision while maintaining structural simplicity.
2Measurement precision
If a separate detection part is added to the key, then detection precision improves, but device complexity increases
Solution Approach 1:
The patent merges the detection part with the key structure itself by integrating the coil and magnetic material directly into the key assembly. This merging eliminates the need for separate detection components, thereby improving detection precision while avoiding increased device complexity.
Solution Approach 2:
The detection part integrated into the key serves multiple functions: it acts as both the key structure and the detection element. This multi-functionality approach allows the same component to fulfill both mechanical and sensing roles, improving precision without adding complexity.
3Ease of operation
If the adjustment weight is used only for touch feel adjustment, then touch feel is optimized, but device complexity increases due to additional detection parts
Solution Approach 1:
The patent makes the adjustment weight serve dual functions: it adjusts the touch feel by modifying the hammer weight and simultaneously acts as the detection part for key displacement sensing. This multi-functionality eliminates the need for separate detection components, optimizing touch feel without increasing device complexity.
Solution Approach 2:
The adjustment weight performs self-service by fulfilling both its traditional role of weight adjustment and the additional role of detection. The magnetic material within the adjustment weight enables it to participate in the detection process automatically, eliminating the need for separate detection mechanisms.
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 configuration allows for highly accurate detection of key displacements, enhancing the touch feel and simplifying the instrument's design by using the adjustment weight as both a touch feel adjuster and a detection part, enabling precise representation of slight key movements.
Implementation Method 1
a coil (61) and a detection part (54) formed from a magnetic or conductive body and disposed on the movable member (12, 911, 921). A filter (60) including the coil (61) generates a detection signal from a reference signal
Implementation Method 2
a filter (60) including the coil (61) generates a detection signal from a reference signal, the filter having a frequency response that changes depending on a distance between the detection part (54) and the coil (61)
Data Source
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AI summary
An instrument playing apparatus has: a movable member configured to be displaced responsive to a playing operation of a user; a detection part formed from a magnetic or conductive body and disposed on the movable member; and a filter that includes a coil. The filter has a frequency response that changes depending on a distance between the detection part and the coil, and generates a detection signal from a reference signal.