Inductive Sensor for bed leveling?

Hey guys, just saw this new thing on Thingiverse: [www.thingiverse.com]

Apparently the person has made a bracket for an inductive sensor. Now, I'm quite noobish on this as I have never seen it before.

I'm wondering, is there anyone here using an inductive sensor to measure the distance? And is it reproducible without failure every time you measure?

The sensor used it the NPN DC6-36V LJ12A3-4-Z/BX

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http://www.marinusdebeer.nl/

Those are real cheap on ebay, most seem to be under 5 dollars with shipping. Here's hoping that someone here has had positive experience with these since I want to add bed leveling to my Prusa i3 but would love a fixed sensor instead of one on an activator that flips down like I was planning.

I believe that is based on the sensor now being used by PrintrBot. You might find more information on it through there website.

Not sure if this would apply to traditional cartsian designs, but delta printers are starting to use force resistive sensors (FSR) along with trinkets or custom circuit boards to trigger the Z-min endstops when bed leveling. The sensors sit under the print bed. When the hotend touches the bed, it changes the resistence of the sensor, triggering the endstop so that the firmwares calibration code knows the coordinates of that point. A minimum of 3 points should provide you will a level print surface.

Prior thread that talked about them. Workable, but limitations I think would make them unattractive for bed leveling. They are temperature dependent so different temperatures are going to give you different readings. They also need a decent mass of metal, preferably ferrous, for detection. Glass, plastics, dibond, and probably circuit boards likely aren't going to be enough to trigger it.

I use capacitive proximity sensors, don't like the inductive ones because you are reading under the glass instead of the glass. The temperature effect on the sensor is easily fix on the slicer software.