detect a change in values

[Axiom Crux]

Seems simple enough, Just want to make a patch that when I move a knob that is attached to a constant, it will output a logic hi signal when the constant is being changed, and when it is sitting still, it puts logic low. The end use for this is that I want to make a simple cv recorder with the sample delay module, when a knob is being moved it will record the movements, and when its not, it will keep looping the movements that have been made. I think this could be cool for sound design, make a really interesting sound generating section and then just have 8 knobs that I sit there jamming on, it will make organic loops.

I tried doing some things using >= comparison module, but it wasn't working out, I am not sure that this route will work or not.

[Antimon]

I have tried my hand at this and failed. There's some trickiness involved when you try to delay and feedback logic that I can't wrap my head around.

One idea that leapt into my head just now as I read your post is that you could try to pipe the constant module's output into a highpass filter, run that through a distortion module and after that a logic pulse module. The highpass will always pull a constant value towards zero, but the moment you change the value there should be a little edge that the highpass filter will interpret as a high pitched signal, and let pass through. It won't be loud, but if you distort it enough there may be a detectable signal. That signal will flap around, which is fixed by the logic pulse module set to suitable values.

If I am being to confusing (and Tim doesn't manage to come up with an ultra-optimized DIY trick), I can try to patch something up in the morning (not sure it will work anyway).

/Stefan

[blue hell]

The idea is to delay the signal and then compare the original to the delayed version, if they are different the signal changed. Would that help?

[Tim Kleinert]

Something like this?

EDIT: You can tweak the response time by adjusting the glide rate. I set it to ultra-fast. This might be too hiccup-y for some applications.

EDIT2: The logic gate signal is derived from the absolute differential, so it isn't 64 Clavia units. If used strictly as a logic gate, this doesn't matter, as anything higher that 0 is interpreted as a logic high*. Just FYI.


*hmm, aristotelian drugs...

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KnobMoveDetectTK.pch2
Description:	Detecting knob movements.	Download
Filename:	KnobMoveDetectTK.pch2
Filesize:	1.12 KB
Downloaded:	1589 Time(s)

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[Tim Kleinert]

Addendum (sorry... )

If you want sample-accurate detection of value change (meaning: at full 24 or 96k), this is your ticket:

http://www.electro-music.com/forum/topic-39398.html

[Antimon]

Neato! I knew you'd have a couple of magic tricks up your sleeve.

/Stefan