Michael,

thanks for the links - these are nice pieces indeed... It reminded me, I do have a whole hall-based keyboard at home, I pulled it from junk (from a locally manufactured terminal), so I can try to pull one key tonight to try to play with it a little bit.

However, this is not exactly what I had in mind.

A "normal", "mechanical" switch is sort of "polarity-less", can be used in matrix or other "nonstandard" circuit. I want this "button" mainly for experimenting, e.g. to replace some sensor (which has clean outputs) or similar, and I don't want to be bothered HOW to connect it. In reality, I can always work out the details of the connection, but it takes time and is sometimes a long and boring process, to trace where the lines are going, especially if I don't have the schematics for the gadget to be repaired or tweaked.

Just as a topic for discussion...

Anyway, thanks for the tip.

Jan Waclawek