This is bracket for Inductive Proximity Sensor for auto bed levering function with Marlin firmware.
As My 3D printer was designed my own, this bracket won't fit any of printer however, the Open scad file can be modified as you wish.
The auto bed leveling function works perfect! I really appreciate this function. I should have installed this function much earlier.
To install this function I followed Tom's instruction on Youtube. Thank you Tom !!
https://youtu.be/EcGFLwj0pnA
You can get a sensor on Ebay. It is quite reasonable price.
http://www.ebay.com/itm/LJ12A3-4-Z-BY-Inductive-Proximity-Sensor-Detection-Switch-PNP-DC6-36V-/140907575134?pt=LH_DefaultDomain_0&hash=item20cebef75e

In the Tom's instruction he used 15k and 10K but eventually it was 15k and 2.5k ( 10k and 3.3k parallel) to get it works.