2013-05-14 15:14:43 UTC
Well, the trackball on our Hurco KMB CNC finally died - apparently a
common problem for machines of this particular vintage - and a web
search for a replacement found us gizmos in the $250-$800 range which
was a bit much for my Scotch ancestors...
So I figured out a $40 replacement...
From a web search I found that what usually gives out is the little
sponge donuts on the optical encoders that the ball contacts. That's
what happened to me, too. Although replacing the donuts was an option, I
went for 'Plan B'.
I probed around in the Hurco and found the optical encoders were
outputting relatively standard 5 volt signals in phase quadrature just
like other optical encoders we use.
And I figured most any computer trackball can probably do the same thing.
So I tottered off to Fry's and got the cheapest trackball on the shelf,
popped off the cover and probed around inside it and found the X-Axis
and Y-Axis quadrature signals, kludged some wires from the new trackball
to the Hurco and voila! we're back in business for $40 (the cost of the
new Kensington trackball) plus a couple of hours of my time.
With the new trackball double-stickied to the Hurco control panel it
looks like our machine is being assimilated by an extra-terrestrial...
but it works for now.
I probably only postponed the inevitable of converting the Hurco to a
PC-Based CNC driver, but it was a fun project for the day.