A trick to measure velocity

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amundsen
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Posts: 62
Joined: 04 May 2013 19:11

A trick to measure velocity

Post by amundsen »

Hello,

I just thought about this trick to measure velocity : measure the time between two events. Actually that's how it's sensed on electronic keyboards.

Here's a layout illustrating that.
velocity test 1.jzml
Velocity test from RB
(6.36 KiB) Downloaded 84 times
Swipe over the two pads from top to bottom. If you take longer than 500 ms then velocity is 0, otherwise it's inversely proportional to the time interval. The values have been scaled to the usual MIDI range but it's not mandatory of course.

However the time sensitivity is limited by Lemur's framerate which is 60 fps, so there's at least 16 ms between the two measurements. And the possible number of values is restricted to something like 30 because of the maximum interval chosen, 500 ms, which is already quite large. With a shorter interval, it would be worse.

I wonder if this framerate is a Liine's choice or if it comes from Apple. Any idea ? Couldn't it be increased ?
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