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Subject: Re: Kurzweil MIDIboard: poly pressure vs. CS-80

From: "David Rogoff" <david@...>
Date: 2004-10-01

--- In yamahacs80@yahoogroups.com, David Evans <dfevans@b...> wrote:
> On Fri, Oct 01, 2004 at 02:19:32PM -0400, marzzz@a... wrote:
> >
> > Actually, many manufacturers don't implement PolyAT because of: 1)
the cost-
> > you need separate sensors for each key; 2) Ensoniq (?) has a
patent regarding
> > PolyAT that they refuse to license;
>
> My understanding is that that's not quite true. Ensoniq has (or
had; it
> may have expired by now) a patent that covers most ∗cheap∗ ways one
might
> implement poly AT. Thus only the expensive options are left.
>

I've read this too. Does anyone know the patent number? I just
searched on http://patft.uspto.gov/netahtml/search-bool.html for
Ensoniq and found 38 patents, none related to this. Patent 05376752
describe a synthesizer and mentions aftertouch, but it's so
vague that I can't tell if this is the one (I don't even understand
half of what my patents say, after the patent attornies got done with
them).

What is in the CS-80's sensors? I know it's a rubber cushion and,
according to the schematics, electronically it acts like a
potentiometer, outputing a voltage proportional to the pressure, but I
don't know what's going on inside it. Are there (widely, cheaply)
available force sensors that could be used to add pressure sensing to
an existing keyboard (if you could figure out where to mount them)?

David


David