How would I edit Marlin so Auto Level (G29) probes areas twice?

I want it to prob it, move up, then probe it again and take it's average. Can this be done?

Rich Cattell's Marlin by default probes then confirms the probed position by performing a repeatability test ie a second probe, before moving on to the next point.

I wrote a simple macro in pronterface to probe the towers three times with G30. The result got printed out in the status window, and I could average the numbers myself.

Tower A:

G1 F4000 X-124.8 Y-72 Z20
g30
g0 z20
g30
g0 z20
g30
g0 x0 y0 z100

Maybe you have to replace the coordinates to match your printer.
-Olaf

If you do not understand C at least a bit then this post is not for you.
Here is a patch which probes each point 5 times and uses results only from the middle 3 probes (ignoring the first and the last one).
[github.com]
It would be better to ignore probes with the biggest and the smallest deviation but I did not bother in Marlin. I have that in Repetier though. You can modify the Marlin patch the same way.

Quote
hercek
If you do not understand C at least a bit then this post is not for you.
Here is a patch which probes each point 5 times and uses results only from the middle 3 probes (ignoring the first and the last one).
[github.com]
It would be better to ignore probes with the biggest and the smallest deviation but I did not bother in Marlin. I have that in Repetier though. You can modify the Marlin patch the same way.

This worked perfectly! Thank you. I might put my own twist on this too

Go on improve it whatever way you like
I think the best thing would be to either remove properly the probe which led to maximum difference and the probe which led the minimum difference and then compute the average (as I have it on Repetier). Or remove only the first probing, or none.

Anyway it prints what values were probed in sorted order so you can look quite easily how well your probe (and the printer) works.
I know from the printed values that my probe measures the same value almost always. Sometimes there is one micro-step difference. And it is a very simple microswitch probe. Nothing fancy.