Finger detection

[Aart van Beuzekom]

Hi,

I'm looking for a key that not only can switch but also detect if a
finger is present on the key. Preferrably no touch-screen-like solution,
but rather a piezo-electrical single key for PCB mounting. I've been
searching the complete internet for the latter, without finding any
solution. The nearest I come is a piezo switch that gives out open or close.
Does anyone have any suggestions? Or comment why nobody invented a
simple piezoelectrical key yet?

Thanks,

Aart

 

[Tim Shoppa]

Or comment why nobody invented a
simple piezoelectrical key yet?

Today's keyboards are crappy enough. Piezo keys would make them worse
especially with regard to tactile feedback, it'd be as bad
as a membrane keyboard.

The very best keyboards I ever used were Hall-effect switches, probably
cost $1000 for an ASCII keyboard in the 1970's when that was real
money. What made these so good is that the switch just moves a magnet,
it doesn't have to make electrical contact with anything, so they can
make mechanics just right to give the perfect feel to the typist.

That said, I think what you want would be called a "touch switch" or
"capacitance switch" or "capacitance proximity switch" and consists of
a metal sensor pad.

Tim.