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SubjectRe: Keyboard error
On 13 Aug 1997, Matthias Urlichs wrote:

> hpa@transmeta.com (H. Peter Anvin) writes:
> >
> > The annoying part of all of this is that this could easily be reduced
> > to a non-issue if keyboard manufacturers would only put a diode in
> > series with each keyswitch...
> >
> What, 111 diodes? At $0.01 each?
>
> Nah, that'll kill the profit margin.

Scarry. You can't rely on diodes anymore. They require a connection that
will carry some current. Many keyboards now use a change in capacity to
detect if a key bas been struck. This allows a wiring pattern to be
painted on (no printed circuit with co$tly metal). The keyboard uP is
emulated also. US$1.01 in hardware, a million is software... but software
is free <grin>.

Cheers,
DJ
Richard B. Johnson
Analogic Corporation
Penguin : Linux version 2.1.44 on an i586 machine (66.15 BogoMips).
Warning : It's hard to stay on the trailing edge of technology.
Linux : Engineering tool
Windows : Typewriter


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