[sdiy] Need some advices... cd4049 touch switches

Jean Bender lofideadbeat at gmail.com
Fri Jan 24 19:15:00 CET 2014


Hello !

I'm turning around some schematics, and i found this one :
http://yusynth.net/archives/WirelessWorld/Chatterbox-1976.pdf

I'm not interested yet by the formant filters, but.. the touch
sensitives switches ( shown on P6, on the whole schema). I don't
really figure how they work. I've tried to breadboard one with my
cd4049UBE, but it doesn't seem to do anything.

I'm powering my breadboard with a 13,3v supply. With the bias built as
shown in the schematic, i can get around 6v at the CD4049 inverter
input, when i'm touching the points, it's going down, but i don't have
nothing at the output. Still at 0, touching points or not.

Could somebody explain me how it should work ? I mean, i think i get
the idea, but i can't see where i'm wrong. Maybe my component ?

Anyway, if you have ressources about body controls and way to build
touch switches, i'm really interested..
Thanks !

Jean

-- 
Jean Bender

Hak Lofi Record

ELECTRON CANON



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