Probing and motor control recommendations

[Carl Mikkelsen <cmm-at-alum.mit.edu>]

Good morning,

I'm curious what others are using for probes.

For my Stewart Platform 
"http://www.foxkid.net/cmm/platform/project-notebook.html", I'm using a 
switch placed where the cutting tool would otherwise go.  It suffers from 
various mechanical problems, as well as the inability to get any kind of 
proportional measurement.

Photo: 
http://www.foxkid.net/cgi-bin/next-res.pl?home_album=/Processed/Carl%27s%20Projects&basedir=./Processed/Carl%27s%20Projects/Stewart%20Platform/Truck%20Signs&res=svga&name=PA250761.JPG&album_name=Truck%20Signs

Sorry for the long URL -- it is made automatically by my photo album software.

I have not converted to using EMC for my motion control, but I'm looking 
into it.  I am planning to build new motor drivers using the Allegro 3957 
microstepping controller.  Does anyone have experience with this chip?  The 
feature I like is that it is directly controlled with a binary current 
value, rather then a step-and-direction interface.  Should I be looking at 
other chips as well?  Are there particular issues or styles of interface 
which are more compatible with EMC?

If this is the wrong place to bring these questions, I am most open to 
being redirected somewhere more appropriate.

Thanks,

-- Carl


Carl Mikkelsen
cmm-at-alum.mit.edu
www.foxkid.net