Easel-Friendly Touch Plate

I started thinking that there’s got to be a better way to connect a touchplate without soldering in more pins on the Arduino or playing with external programs like UGS and Chilipepr. I give you the Easel-Friendly Touch Plate:

The idea behind this is that three individual aluminum plates are connected together, but separated by electrical insulators. Each plate has a wire that goes to the NO terminal on the corresponding homing switch for that axis. A clip connects to the bit that pigtails and connects to the COMMON terminals on all three limit switches. Instead of the switch closing the circuit, the circuit would be closed when the bit contacts the plate for each axis.

One useful variation I can think of is to have 1/8" plates attached to the bottom, in an identical position to the X and Y axes plates. This would allow the user to place the place on the workpiece, home, then remove the plate and adjust for height.

A few bumps in the road are:

  1. The Z-axis would have to home “down” instead of “up”. I’m not sure if that’s something Easel can do or not. If not, this could be made to work with just the X and Y axes.
  2. The homing travel speed would have to be slowed down significantly, otherwise the bit could get damaged. This could be minimized by pre-positioning the bit near the desired “home” point, but it would still be risky if the bit was small (.03125") and fragile.
  3. The electrical insulator would have to be positioned fully between all 3 pieces. Maybe one could use a few sheets of paper and epoxy, if the cured epoxy provides enough resistance.


Have you looked into the “probe” gcode command? Grbl supports both the homing command and the probe command, so they should both be Easel-friendly. Since you typically are only probing in a single direction at once, you don’t need separate signals for each section of the plate.

I get what you’re trying to do with the triple touch plate though, it’s very clever :slight_smile:

If that can be done through Easel, let me know and I’ll be a very happy feller!

can it be done through machine inspector?

I tried some g-code before and it did not work. :frowning:

If nothing else, I think I can Z-zero with a washer or piece of aluminum embedded into the wasteboard and a wire running through a AA battery to an alligator clip. That wouldn’t be nearly as much fun as epoxying together some aluminum at exact right angles though. :smile: