[sdiy] Piezo keyboard

[harrybissell]

john mahoney wrote:

> I don't know if the anodizing has to be removed or not -- is it an
> insulator? Since it's a natural color you wouldn't see much difference
> either way. However: Bare aluminum gets covered by a thin, black oxide that
> isn't very visible -- until it's all over your fingers. Yuck!

Aluminum Oxide is an excellent insulator... often used in thin layers under
power semiconductors for thermal conductivity and electrical isolation

(beryllium oxide is twice as good... but breathe the dust from it and you're
dead...)

All exposed aluminum should be considered aluminum oxide... the layer forms THAT

fast .  Anodizing would not affect this much, just makes a hard surface layer

(did I mention that aluminum oxide is HARD too... you can make sandpaper out of
it...
in fact they often label it Aluminum Oxide paper <funny, that...>)

If you wnt with a capacitive approach, there would be no reason to remove the
anodizing.

H^) harry

>
> --
> john