DIY 3D CNC touch probe.

If you have not, please watch this video first:

This probe is quite simple compared to other ones i have seen, is easy to build and it works quite well.
I'm going to explain how the probe works, this way you could build something similar but with very different materials.

A probe ussually have 2 parts: one fixed and one that moves when it touches something.
In this case i used a rounded plastic box as the fixed part and a piece of plywood with an spring to keep it in place, some screws that make the contacts and one old tiny precision screwdriver that makes the touch: 

The idea of a probe in kind off interruptor that breaks continuity when it touchs something.
For that, in this kind of probe we use two parts like this, three connection points, two of then are electrically connected and the third connected to a cable:

In our case this corresponds to the aluminium pieces in the fixed part like this:

In the moving part is more obvious; tree screws, two of them connected by a wire and the third to a yellow cable.

then if we make the two parts touch this way, any movement in the moving part will separate one of the tree crews from the base breaking the circuit:

I used aluminium pieces in the fixed part to allow some missalingment, this way it can be built without high-precision finishing and still works quite well.

As an example of the precision you can get with this probe i scanned a 1 Eur coin:

Well... i scanned just part of it because at this resolution it takes too long to scan the whole coin just to test it.
This is the result:

Not too bad...

To see how i scanned have a look to this entry:

And this video:


  1. Thank you so much for posting the description of your touch probe!
    I made a copy of it and it works great! I documented it here
    ... together with a couple of my own diy probes, scroll down.
    Best wishes, Martin

  2. Great!
    Very well executed, that's hi-tech compared to mine :-)))
    The adjustable spring is also a great idea.

    And your website is full of interesting projects.
    I will have a closer look...

    Thanks for your feedback.
    Have a nice day.


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