This is complete set of files to reproduce fork of David Crocker's Mini Differential IR probe. Desing is slightly changed. Implemented on Geeetech's acrylic I3 X clone of Prusa I3 3D printer.
It was more quick and cheap to create own PCB for this probe. Gerber files were generated using Spurkfun cam profile, copy is placed in separate directory. Firmvare and schematics used can be found at original DC42's GitHub, version 1.1.
The simplest way to attach this probe to acrylic Geeetech's I3 X is to print out modified version of I3B1-31 bracket. Design is done using FreeCAD (v0.15) instead of Solidworks, for GLP purposes. Holes for screws are only 1.8 mm diam, because it is more simple job to drill exact diam for screws you will use instead of correcting CAD file. But if you would like to change something - check modified bracket directory.
This probe is connected to Z_MIN wires on GT2560. If you version of board has only 2 pins, as mine, connect GND to Ground pin of Z_MIN switch, OUT to second pin. Vcc +5 Volts you can obtain from pin on connector for motor driver.
Very first step - applying firmware code changes to you Marlin. Modified configuration.h and configuration_adv.h can be found at Marlin there. Or you can do modifications you need to your specific Marlin by youself. All things you should do after uploading modified firmware are described at Daviv Crocker's page, mentioned above.