Is this the same pinout on the Blue Smoke?
Also couldn’t you just run 1 wire and use ground from Z axis motor? Is there a spare wire in the Z motor wiring, could tap into that to use for signal and rewire at board end to avoid running new wires all together.
I would run separate wire for a probe, maybe even use Cat5 and some Breakout Boards I think SparkFun has them.
Thank you
Apologize if this has been posted somewhere, what are you guys using as your probe to clip onto the bit? I can’t get anything down in there to clip onto the bit? I got this to work, but with the sled on my table. I can’t get to it when it’s hanging. 
You don’t have to clip on the bit, just clip onto any metal part of the router. It should all be grounded.
Inwas thinking to just attach a magnet to the cable and throw it to the router for a connection. 
Thanks. I’ll give that a go. I tried it somewhere else on the router (the bit holder?), but it didn’t work. Appreciate it.
So, I got my ruler a while ago, but had never got around to getting this set up. As I go through a few changes I’m going to be making with my Maslow, I was looking into this again. The only question I have is how do you account for the difference in the thickness of the ruler. It is a standard metal ruler I got at Walmart, and haven’t actually measured the thickness. In looking at the G Code and reading this post, I can see the command to lower and touch, and know this now sets the point of touch as the new zero. But let’s say the ruler (or whatever someone is using) is 2mm thick. Won’t that set the zero 2mm higher than it actually would be? How do you account for that off-set?
Not if the ruler is flush with the bottom surface of the sled which rides on your cutting surface.
DOH…duh…okay…I wasn’t thinking about that. the Zero is set to the “bottom” of the sled (which should be the top of the work surface). I don’t know why I didn’t think of it that way, but it makes way more sense! Thanks @Orob!
I am hoping I can get some clarification on the wiring. I connected the grd from aux 4 to the router and the vcc (center pin) to the ruler and it seemed to work. When I read your post again I think I might have it wrong?
You use the signal and the ground pins from the aux 4. It really doesn’t matter what you clip where just so that when they touch the circuit is closed. Clip one on the metal ruler. And one on the bit or metal on the router ensure that it has continuity to the bit. (I sandwiched a wire under a housing screw so I didn’t have to try and detach the clip from the bit with my big dust shield in the way.)
Make sure the touch plate option switched on through the advance settings. I think the default distance is 10 mm it will travel unless it hits the plate first, so make sure you are under 10 mm when u use the zeroing feature, else you may not get a true zero.
-Tim
Thank you for the write up younger me, i was installing my maslow again and forgot which pins i needed for this.