Metallic touch pads generally work by detecting a change in capacitance
caused by your finger touching it. A very high frequency signal is generally
running through the pad. You can look on the PAIA site for some old schemos
of their drum pad thingie that used this technique. You can get velocity and
pressure sensitive signals out, if I remember correctly.
One caveat: it needs just a little moisture on your fingers (e.g. your
normal sweat is usually enough) to work well.
Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@... > -----Original Message-----
> From: Nathan Hunsicker [mailto:nate@...]
> Sent: Friday, March 31, 2000 1:36 PM
> To: motm@onelist.com
> Subject: [motm] Maybe a little OT, maybe not
>
>
> Does anyone on this list know what sort of technology was used on the
> metalic keypads used on microwaves made in the early 80's? I had a
> Panasonic that had a touch pad on it, the buttons required no pressure to
> activate, just a touch. I'm trying to find out if the keypad was made of
> some expensive material or it there was extensive circuitry required to
> make these touch sensors work. the reason I ask is, I was thinking about
> some type of linear controller using pads similar towhat I was describing
> hooked to a resistor chain fed through a sample & hold and a lag processor
> to somewhat mimick a ribbon controller (since that idea is now officially
> out the window) Let me know what you think. -Nate
>
>
>
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