K8200/3Drag Auto Bed Leveling with 8mm Proximity Switch

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Correct bed leveling is essential for good prints - Marlin firmware now has this awesome feature of measuring the bed and automatically adjusting the Z axis when printing.
As this YouTube video demonstrates.

I had a small used 8mm inductive proximity sensor (IA08BSN40PC) from an earlier project. It is compact, but I think, expensive from new...

The sensor will detect detect a metal bed (not glass, etc.) from approximately 3mm. It must be supplied with 6 - 36V and has an output just below the supply voltage.
Output must be converted to 3 - 5V before connected to the controller. This is done with two resistors and one zener diode as shown on the picture (before protected with shrink tube).

There are a lot of good guides to setup the firmware and activate the auto bed leveling feature. Tom's Guide has a good video explaining the setup.

References:

• Marlin on GitHub
• Inductive Proximity sensor datasheet