[sdiy] Mod Wheel Thoughts

[drheqx]

I think Harry is right about the gradient being on film. There may be a
few opportunities using colored filters as well. 

http://www.heqx.com/wheel.jpg
 

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Ray Wilson
Sent: Sunday, March 13, 2005 6:25 PM
To: harrybissell; john mahoney
Cc: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Mod Wheel Thoughts

I did say mod wheel but I'm going to see if I can get this to be useful
for 
both pitch bending and modulation.
I will definitely write back when I have something to show. Will it be
Fame 
or Shame!

Thanks again for everyone's input.

Ray


----- Original Message ----- 
From: "harrybissell" <harrybissell at prodigy.net>
To: "john mahoney" <jmahoney at gate.net>
Cc: <synth-diy at dropmix.xs4all.nl>; "Ray Wilson" <raywilson at comcast.net>
Sent: Sunday, March 13, 2005 6:28 PM
Subject: Re: [sdiy] Mod Wheel Thoughts


> The flat area, with a single cell... is a loser.   The cells have a
really
> poor thermal stability, so changes in temperature render the optical
> flat useless.
>
> You might do differential illumination on a center-tapped cell... at
least 
> the
> two halves would track.
>
> I think trying to null the center is too hard. I'm thinking "mod wheel
= 
> good"
> "Pitch-wheel = bad"
>
> H^) harry
>
> john mahoney wrote:
>
>> > Ian's thought about the stable initial position makes me think I
need 
>> > to
>> > come up with some sort of
>> > stable mechanical detente at the initial postion. I think I will 
>> > combine
>> > this with electronics that have a sort
>> > of threshold. The circuit only responds after a minimum movement.
>> > Making this unnoticeable will challenging.
>>
>> You could try an "optical detent" -- an area of 50% gray in the
center
>> section of the gradient. Here's an exaggerated (and poor quality!) 
>> version
>> of what I mean:
>> http://www.bitshifted.com/images/gradient.gif
>>
>> I am assuming that 50% gray yields a 50% CV output, though I don't
know 
>> how
>> linear the CDS response will be.
>>
>> A sliding shutter, cut at an angle, seems like a great way to avoid
the 
>> need
>> for a high quality gradient. Analogous to my optical gradient
example, 
>> you
>> could put a flat area in the middle of the shutter.
>> --
>> john
> 




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