Quote Originally Posted by Tenson View Post
That's clever! How do you implement such a an auto-z sensing circuit for Mach3?

It would be similar (I don't use Mach3 now but have in the past)...normally with Mach 3 there's a Z auto tool zero vbscript where you need to enter the thickness of your touch off sensor (a lot of people use PCB material so therefore a thickness of 1.6mm), so you'd just use that same VBscript for a thickness setting of 0 (on account there is no 'sensor' height in play becuase your stock copper pcb surface is now your touch off sensor surface!). So when I change tools, I send my axises to X0Y0 (which is never milled and therefore always has electrical conductivity back to the aluminium clamp) and touch off.....you can't get any more accurate than touching off on the surface you are going to mill!! I'lll take a piccie later.

Re the tool sensor wire itself ...you just run the wire back to a free 'pin' on your board (which has a pull up resistor on it) & then configure Mach3 on the ports/pins page. Plenty of how tos wrt auto tool zero & mach3 on the net.