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Re: Potting compounds

 From: Mark Willis <>
>Could definitely use conductive plastic for the bottom of the keycaps,
>the problem's that I just don't like the "feel" of most conductive
>rubber switches - I like the tactile switches a lot better, you can
>tell whether you've pressed a key or not!  Some of the little "snap
>dome" switches are pretty good, I think research here would be good <G>
>
>Think centrifuges to de-bubble the mold;  Works better than a
>vibration table, 5-6 G's does a very good job <G>
>
>In this tiny of a keyboard, there really isn't room for a spring in
>there, easily.  Good challenge for time when I'm waiting for someone,
>with my family I get to do that a bit.  Maybe a spring that is behind
>the PC board or something.

Or you can take the lead that some of the sun keyboards took: they just
put traces on a pcb, made them exposed in specific areas, and instead
of springs or rubber, they used foam with some sort of conductive foil
on the bottom. I'm not sure how they kept the key off of the contacts,
but I leave that as an exercise to the reader 8>

Scary, but it works!  cleaning is a breeze, too. one wipe with a tissue
will clean all the dustbunnies from the surface of the pcb, since
there's nothing sticking up to snag on.

   - Kevin

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