Test Pattern Generator

I’ve put together an attempt at a fairly simple test pattern generator.


The idea is that it generates g-code as text that you then copy-paste into a text editor.

This draws “rulers” along one, two, or four edges of a rectangle. This is mainly aimed at seeing whether steps/mm is accurate, and also could show if it is nonuniform, or if there is “backlash”.

I’d be interested to hear your thoughts!


That is pretty slick. FWIW, this is the code that sandify uses to download the gcode:

link to data url. nice idea. before that I saw that usually data used for small embedded images

I’ll have to give that a shot. Thanks for the tip!

Again thanks to Jeffe for the tip on downloading g-code. Magic to me but it works.

I’ve added another test pattern that can indicate whether the surface is flat and level. It moves the pen in a “kissing” motion that lowers and raises diagonally like this:

[attachment file=100271]

The length of the line will amplify any Z variation in the surface location.

On mine, my surface is not particularly flat or level. I haven’t faced the surface with a cutter, so it is about as level as I would expect. You can see the “X” marks toward the bottom are larger than the “X” marks near the top.

[attachment file=100272]

This test pattern could potentially also indicate the presence or absence of backlash in Z, which would appear as asymmetry in the “X” marks. But asymmetry doesn’t automatically imply backlash because the pen might have funny asymmetrical behavior when the line starts vs. when it stops, so that has to be considered.


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As that comment suggests, it’s magic to me too :slight_smile:

Great idea. It’s a great visual.

Whoa, that is a great pattern and idea, nice!