Electronic Keyboard Key Speed Detection Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electronic pianos face challenges in detecting key depression and release speeds due to the need for a large counter scale and circuit size, which increases complexity and cost when trying to cover the dynamic ranges of both speeds.
Innovation Solution
An electronic keyboard instrument with a key speed detection system that uses multiple key switches and a counter to differentiate between key depression and release speed detection periods, adjusting the resolution and data bits to maintain a compact circuit design by making the key release speed detection period longer and reducing the resolution of key release speed data to match the data bits of key depression speed data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the counter scale is increased to cover both key depression speed and key release speed dynamic ranges, then the detection capability for both speeds is improved, but the circuit scale and complexity increase
Solution Approach 1:
The patent divides the key speed detection into two separate time periods: key depression speed detection period and key release speed detection period. By segmenting the detection process temporally, the system can use different counter scales for each period, avoiding the need for a large counter that can handle both ranges simultaneously. This segmentation allows the counter to be optimized for each specific detection task, reducing overall circuit complexity.
Solution Approach 2:
The patent dynamically adjusts the counter scale based on the detection phase. During key depression detection, one counter scale is used, while during key release detection, a different counter scale is applied. This dynamic adaptation allows the system to maintain appropriate detection precision for each phase without requiring the counter to be sized for the maximum possible range of both phases simultaneously.
2Measurement precision
If the key release speed detection period is made longer to improve detection accuracy, then the measurement precision is improved, but the resolution of the detected speed decreases
Solution Approach 1:
The patent applies different resolution levels appropriate to each detection phase. For key depression speed, a higher resolution is maintained because the detection period is shorter and the speed range is more limited. For key release speed, since the detection period is inherently longer, a slightly lower resolution is acceptable and intentionally applied, trading some precision for the benefit of maintaining a compact counter scale while still achieving sufficient detection accuracy for the slower speed range.
Data Source
AI summary
When a key depression speed and a key release speed of a key is to be detected based on a value of a counter (44) which accumulates a value every time the key passes through key switches (SW1, SW2), a number of digits of data indicating the key depression speed, a unit of the data being a bit and a number of digits of data indicating the key release speed, a unit of the data being a bit, are made the same.