Increase Bed Mesh Size for SBC users

[Hernicz]

I would like the bed mesh size to be increased to 100 x 100 (10K points) for SBC users.

As far as I know we are limited to 441 points because of the memory limitations of the MCU.

[jens55]

@Hernicz, while I often wished for a larger mesh (although I run standalone), it takes me a solid two hours to do a 441 point mesh probe. With a 100100 mesh grid, that would be a 44 hour mesh probe run and I can pretty much guarantee a power failure, power spike or an inconsistent probe reading after 43 hours
Note that I am not saying that your suggestion is wrong, just that 10000 points seems a bit excessive. I don't think I would ever try and run a mesh bed probe larger than maybe 3030 or 900 points. But hey, that's just me ....
BTW, it takes 2 hours because my BLTouch is somewhat inconsistent so I am set up for multiple probes per location (up to 10) to make sure I get two successive readings that are close to each other.

[o_lampe]

@Hernicz Mesh levelling is part of the planner, so we need the mesh in local memory. It would be cool to look-ahead and constantly swap the next relevant mesh points between SBC and Duet, but that's a risky idea.

[Hernicz]

I think preparations has to be made for faster probing methods.
BEACON - 2000mm/s bed probing

I modified the firmware, just about to do a test print to check if I actually able to print anything with a mesh like this.

Took 1 hour 10 min at low (0.01 mm) precision with a BLTouch in fast mode. Fast BLTouch Probing

[jens55]

Absolutely insane! Alas, I am using a glass bed and RRF so no joy for me

[Hernicz]

@jens55 This is RRF, but I modified the source code and compiled a firmware .bin file.

[Hernicz]

@o_lampe Can the planner run on the SBC?

[dc42]

@Hernicz said in Increase Bed Mesh Size for SBC users:

I think preparations has to be made for faster probing methods.

That's already done in RRF 3.5.0-beta.4. We'll likely increase the maximum supported number of mesh probe points on Duet 3 boards too.

However, I question whether there is any need for as many as 10000 probe points even if you can scan them quickly.

[Hernicz]

@dc42 That's good to hear

I don't know what the future might bring, but I'm certain we will not need more than 10000 probe points for a while.

Also 10K is nice round number

[o_lampe]

Such a high count of probe points is almost begging for a 3D-scanner like setup. With cameras and flashlights you can produce a cloud of millions of probe points in no time...then filter out the polygone-planes that are equal to the neighbours to compress the file.
Some smartphones can do that too. Maybe add a phone gimbal to the printer and let the smartphone scan the bed...