Keyboard Key Displacement Sensing With Coil-Filter Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing techniques for detecting key displacement in musical instruments, such as those using electro-magnetic coupling, struggle to generate highly accurate detection signals for slight key displacements due to limited changes in current flow through coils.
Innovation Solution
A musical keyboard instrument design that incorporates an adjustment weight with a magnetic or conductive body, which serves as both a touch feel adjuster and detection part, and a signal generator with a coil and capacitive or resistive elements to generate a detection signal that accurately represents key position changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a coil and metal plate configuration is used to detect key displacement, then the structure is simple and easy to manufacture, but the current flow through the coil does not change substantially responsive to displacement, resulting in poor detection accuracy
Solution Approach 1:
The patent changes the electrical parameters of the detection circuit by introducing a signal generator that outputs a rectangular wave signal, combined with a capacitor connected in parallel with the coil. This parameter change transforms the detection mechanism from direct current monitoring to frequency-based detection, enabling high-accuracy detection of slight key displacements while maintaining structural simplicity
Solution Approach 2:
The patent replaces the conventional direct electromagnetic detection method with an oscillating signal-based detection system. By using a signal generator to produce rectangular waves and detecting changes in the oscillating current through the coil, the system achieves higher sensitivity to slight displacements without complicating the mechanical structure
2Measurement precision
If the detection part is separated from the adjustment weight, then the detection function can be optimized independently, but the instrument configuration becomes more complex
Solution Approach 1:
The patent makes the adjustment weight serve dual functions: it acts as both the mechanical adjustment component for touch feel and as the detection part for sensing key displacement. The adjustment weight contains a magnetic body that interacts with the coil, allowing one component to fulfill multiple roles and avoiding additional detection mechanisms that would increase complexity
Solution Approach 2:
The patent merges the adjustment weight and detection part into a single integrated component. The adjustment weight incorporates a magnetic body that serves as the detection target for the coil, combining the mechanical adjustment function with the detection function in one element, thereby simplifying the overall configuration while maintaining detection accuracy
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 design allows for highly accurate representation of slight key displacements by varying the amplitude of the detection signal in response to key position, simplifying the instrument configuration and enhancing detection accuracy.
Implementation Method 1
a coil (61) and a capacitive or resistive element, and is configured to generate a detection signal from a reference signal
Implementation Method 2
an adjustment weight (50) configured to adjust a touch feel of each key (12) of the keyboard (10) when the user operates the key (12), and a detection part formed from a magnetic or conductive body and disposed on the adjustment weight (50)
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
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.