KEYTouch ABL©

Hello 3D printing community

Here is my way of doing the ABL on an Ender3.
You just need a NC microswitch and an Allen-Key, so no need for fancy or expensive other things.
The accuracy it is very good, I did get on M48 a rang of 0.012 with a standard deviation of 0.003,
Basically, the idea I did take from inside Marlin where I have seen the allen-key was used in delta printer.

So here is what I have done:
I did connect a new micro-switch in series with the one from the Z end-switch to work as a new input, so no need for a PIN27 or the other one that is free (PIN29). Also is no need for extra device to match the voltage or the polarity.
Here is a fritzing drawing of the wiring connections.
No matter how you make it physically but the result should be something like that, the wire have to be at the pins that have continuity when the switch is not pressed, is called NC or normally closed!

You need to enter somehow in between, so or you just cut the wire and connect there o