Digitizers, $130 Signal Lite, $49 Enco Edge Finder

Doug Fortune wrote:

> re: designs to make a digitizer sensor
>
> On the other hand, rather than building a new device, one could
> use something like the $130 "Signal Lite" which I found on page 2130
> (PN#06499479 ) of the 2000/2001 MSC Supply Company Big Book.
>
> It proclaims to be a 3 dimensional sensor, looking like perhaps 1/4 the
> length of a thick felt pen, with a precision ground RC 60 0.4000 inch
> (+/- .0001") probe diameter, a repeatability of +/- 0.0005",
> and has XY overtravel of 0.1" and a Z overtravel of 0.2"

Ok, since there were no responses to that one, I presume the price
was too rich.

How about this one:
http://www.use-enco.com/hotdeals/mach_tool_acc.htm page 67 .pdf file

Enco Edge finder (on sale for $49.95, PN#AC636-7040) :
- 1" dia shank
- 0.000 20" T.I.R.
- Precision ground, hardend to 60 R.C.
- 4 highly visible lights (which we'd have to wire back to the controller)
- batteries ARE included!

Now I suppose this has no tolerance for running into things (overtravel),
so using it as a digitizer (at higher speeds) will involve mounting it so that
its mount will "give" when it hits the object. Think of a spring that will
flex upwards and/or to the sides, and we must be able to know when the
mount is not at "home" (ie rest position). Of course a spring is too
vibration prone, so we need other suggestions from you guys.

Maybe a gimbel-type setup, that is quickly recentered by magnets? or....

Doug Fortune