[sdiy] Touch Controllers

[John L Marshall]

Scott,

I think that you are correct. The individual finger pads are a probably a
capacitive pad. I had always assumed that each pad was part of a bridge
circuit driven by a frequency above audio. The output of the bridge is
rectified and filtered to give a DC control voltage. There may have been an
article about the technique in the Electronic Music magazine. It has been
too many years.

Take care,
John
www.sound-photo.com
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----- Original Message -----
From: "Scott Evans, Gen Mgr" <esresource at earthlink.net>
To: "DIY" <synth-diy at dropmix.xs4all.nl>
Sent: Monday, January 20, 2003 3:15 PM
Subject: [sdiy] Touch Controllers


> Hello all,
>
> After reading the interest in the ribbon controller ideas, I got to
> thinking about touch controlled interfaces such as the Buchla 100 and
> 200 interfaces as well as the Serge TKB. I had opportunity to use the
> Buchla 100 controllers years ago, but I have never seen inside one of
> these fun devices. Has anyone in the DIY community done any development
> on these? Or perhaps some information on how the mechanics work? I
> believe these are variable capacitance devices. I would love to build
> something of this nature. Any guidance would be appreciated.
>
> Scott
>
>