>
>
> Unfortunately no I need to reliably and respectably detect movement on
> the order of .001mm or better so spring loaded things wouldn't work
> Basically the idea is to have 3 points of contact and then detect when
> one of them opens.
>
>

Ahh, well the "3 points of contact and detect when one opens" sets off bells
in my head, especially when related to machine tools.  Some CMM systems use
a similar method, where the touch head is connected to a Y shaped piece,
lightly spring loaded against the main housing of the probe head. The main
housing has a saddle for each pin of the Y shaped pin sticking out, (so
actually 2 contacts at each pin)  and it looks for one of the pins to lift
and go open.  (well they actually look for the resistance starting to
increase, but they do all sorts of other fancy stuff which I cant recall)
I could have sworn I saw this on a video on renishaw's website, but cant
find a reference for this again.   Is there a reason a standard tool setter
wont do for you?
-Jon Hallameyer
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