Re: Digitizers, Renishaw (for bill phillips)

Re Digitisers, I like the opto sensor
idea. It means you can optimise the probe
for its mechanical performance and unlike
switches or piezo sensors the optos have
NO mechanical effect on the probe. If I
was designing a high-priced commercial
system it would be opto. :o)

How about a vertical hanging probe, with
like a disc at the top. The disc sits on/in
a ring. The exact mech design I leave to
the experts!

Now if the probe is deflected vertically
or sideways when it is lowered it always
produce lift at one or more corners of
the disc. So if you put two opto sensors,
each at the edge of the disc and at 90'
to each other, you will absolutely sense
any probe deflection.

Electrically it's pretty simple, you just
zero the optos in the "standard" position
and use a high gain amp. Any deviation
gives a "hit" indication. :o)
-Roman