[sdiy] distance meter for keyboard, was: Where to get special white keys?

[Ingo Debus]

Am 28.02.2009 um 21:24 schrieb cheater cheater:

> Then the next very difficult thing to do would be
> to figure out the distance meter for the key: I would probably go for
> something optical, and this assembly could be quite difficult, and
> parts hard to source.

Or you could use an analog (linear) hall sensor and a small magnet.  
This should not be too expensive, and easy to build.

Ingo