[sdiy] Small Resistors and slider pots

[Happy Harry]

This method works well, but you are limited to the speed
of the photocell. I used it to make a hi-hat pedal, where
speed is essential. I had to design the mask so that the
cell is initially dark, and gets a blast of light when you
depress the pedal. OK but mechanically a little harder
(of course not for the stooge, who has the metalworking chops
from hell... ;^)

The coolest method is use by Morley, which uses a fabric
window-shade type material and rolls it over the cell.
I'd have to draw a picture... it is so simple, quiet and
effective. Sort of like a Rollamite

(anyone remember that invention that went nowhere...?)

H^) harry


>From: "J. Larry Hendry" <jlarryh at iquest.net>
>To: <synth-diy at node12b53.a2000.nl>
>Subject: Re: [sdiy] Small Resistors and slider pots
>Date: Tue, 3 Apr 2001 20:11:37 -0500
>
> > ----- Original Message -----
> > From: Glen <mclilith at ezwv.com>
> > A long, long time ago, I saw an optical potentiometer
> > in a catalog. It was a linear, or "slider", style of potentiometer.
> > ----snip----
> > Has anyone on the list seen anything like I'm trying to describe?
>
>Not exactly.  But, when I was in high school (many years ago) I played
>in a band and used a Farsisa VIP233 keyard.  The volume pedal was optical
>However, the variance method was different.  It used a fixed light source
>and a fixed light sensing device.  The pedal pushed a piece of metal or
>some other material between the fixed source of light and pick up that had
>a slot that was very narrow at one end and got wider at the other to let in
>more light.
>
>The more I think about this type of arrangement I think it would be real
>cool
>as you could have any kind of "taper" you wanted on your pot based on how
>the "light slot" was cut.
>
>Larry Hendry
>
>

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