[sdiy] Keyboard trigger...

[Rob B]

Just stick with hall effect for all the keys, to both turn it on *and*
check for velocity (speed) and aftertouch (distance past a certain
threshold). Modern DSPs should be able to do this easily.

You could then do that aweful polyphonic aftertouch too. ;)

I dunno, though, aren't hall effect sensors expensive?

Personally, I would do the capacitive phase change route.

Rob

----- Original Message -----
From: "studio271" <studio271 at mail.ev1.net>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Saturday, February 16, 2002 5:21 PM
Subject: [sdiy] Keyboard trigger...


> I just thought up this design for a synth keyboard trigger using
> magnetic hall sensor ICs, and I just wanted to know if anyone here
> has ever heard of anyone using them to trigger key strokes.
>
> It uses a momentary tactile switch with a soft-trigger (no
> clicking; or is that what "tactile" means?) to a hall sensor stuck
> below the key and a magnet on the bottom of the key. It works
> where when you aren't pressing the key no voltage is going through
> because of the switch, and once the switch IS activated, it enters
> the (calibrated) hall sensor in a way that sends more voltage
> according to how close the magnet is. You'd probably need only a
> small magnet with a relatively small gauss to give a good
> logarithmic response from the hall sensor.
>
> Please give some input on this subject, and thanks in advance!
> (Got good response on my previous TI predicament, and I'll admit
> that it wasn't that big a deal; I just panicked a little!)
>
> -271
>
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