[sdiy] A different kind of polyphonic aftertouch

rsdio at audiobanshee.com rsdio at audiobanshee.com
Sun Dec 17 07:43:43 CET 2017

You don't even need two thresholds.

Velocity is the difference between any two positions, provided that you know the time between the measurement of each position. Since most keyboard scanners run at a fixed polling rate, every scan could produce a velocity by comparing the old and new positions. Negative velocities would simply be release velocity.

You still might want thresholds of a sort, depending upon whether you want the MIDI Velocity to reflect the first velocity measurement after the key leaves the top position, or the last velocity measure before the key hits the bottom position. It would be interesting to see how much they differ, and which corresponds more closely to the feel of the musician.

If you break out of the MIDI paradigm, though, you could have a messaging protocol with continuous position and velocity updates.


On Dec 16, 2017, at 8:45 PM, Mike HEQX <mike at heqx.com> wrote:
> This type of linear sensing can also sense velocity just like two switches do now in most keybeds, just by setting two thresholds. So you get the linear and switching at the same time and it's adjustable. Very useful.

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