ABL in Rich Cattell's Marlin versus Marlin RC 1.1

I am not the only forum member to express an interest in having the same auto bed levelling/tramming/compensation method as used in Rich Cattell's marlin for Deltas applied to cartesian machines. By this I mean rather than implement a plane of best fit based on 3-9 probing points why not probe the bed in 25 places and generate a full height compensation grid and then apply this to z coordinates during print.

What would it take to do this ? I am not a programmer, but would happily contribute/test/do general dogsbody wok for someone willing to tackle this. I am presuming it would be a case of porting the code for ABL from Rich Cattells version over to Marlin 1.1 and in doing so create a new branch.

Sorry to post this disclaimer to shut down the naysayers but I appreciate in an ideal world all print beds are flat to a high degree of precision, but not always level, however in the real world especially if you have a large printer many beds are not flat, but might be fairly close. I also appreciate compared to the relative speed of a delta with deployable z-probe, or even better a nozzle based probe such as force sensing resistors it would be slow to probe a large number of points on a cartesian machine. But I am working on a z-probe such as the one used on the Cel Robox but based on a microswitch inside a hinged x carriage so it can be added to the printer and no hot end changes are required. This should speed up and simplify z probing. The entire printable area of the bed can be probed as there is no offset. Making it nozzle based removes the need to mount and configure probes, measure probe offsets and assuming this method has a high reproducibility will give the exact z height for any given x,y coordinate at the nozzle exactly where this data is best recorded and utilised. This must be a neater solution.

Any ideas - If Rich is reading this I am sure you know what would be required to do this?

Edited 2 time(s). Last edit at 11/24/2015 10:42AM by DjDemonD.

The best way to fight uneven beds is to print on a raft and/or use PIR foam as print surface.

I doubt ( don't say nay ) that a hinged x-carrier can provide the accuracy and repeatability which is required for such a small error.
It starts with loose linear bearings and the flex of the smooth rods ( higher flex in the middle vs. less flex at the ends).
Now add up the friction of the hinge or the effort to make it playfree and smooth running.

Using force sensing resistors on a Cartesian bed is worse, because of the springs and the flex of the Y-carrier.
-Olaf