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Autoleveling with a BLTouch on a CNC Machine

It’s a little interface to use a BLTouch for autoleveling on a GRBL based CNC machine.

This Z touch probe is actually meant to be used for autoleveling the print bed on a 3D printer. But because the machine table of my DIY CNC is not perfectly even, I wanted to use it for autoleveling on non-conductive surfaces, like acrylic. For conductive surfaces, you can just clip a crocodile clip to the milling bit and one to the material and as soon as the bit touches the surface, that completes the circuit which will trigger the probe input. So the BLTouch is not needed in this case. The probe is simply controlled, by sending pulses of different widths. So I simply made a little interface, which sits between the GRBL controller and the BLTouch probe. It has an ATTiny10 on it, which can easily generate those control pulses. A single button was enough for putting it in the different modes: 1/2 Sec. press: Deploy probe 1 Sec. press: Stow probe 2 Sec. press: Stow probe + Alarm release That’s all I need for the moment.

The ATTiny10 was pretty much perfect for this, just had enough pins for everything and it just so happens that I still had a bunch of them laying around.
All the ATTiny is doing, is sending pulses of different widths to put the BLTouch in the desired mode, as well as beeing interrupted when the probe triggers, so it can send out the next command.

The reason I’m inverting the trigger signal is because I’m also using the crocodile clip method, as mentioned above, and every time I switch between that and the BLTouch I’d have to change the “probe invert” setting in the GRBL software.”

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