RoBo3D R1 owners. I wrote up a tutorial on how to add auto-bed height compensation to any current printer
http://forums.robo3dprinter.com/index.php?threads/robo3d-autolevel-via-mike-kelly.2574/
You can also view it on thingiverse, grabcad, and youmagine
https://grabcad.com/library/robo3d-autolevel-via-mike-kelly-1
Give it a read and feedback. Thanks.