Wow, Rick, good work! I'll have to give it a try sometime. Wish I had an extra Mega/Ramps laying around.

I've been building GRBL controlled cartesian plotters lately, and I wish I was knowledgeable enough to write a controller for them. While there are plenty of ways of generating gcode from SVGs and images, they're all either overly complicated for pen plotting, hardware/firmware specific, or fatally flawed in some other way for my purposes. Life would be so much easier if I could do what you've done.

I see your pixel drawing has custom gcodes. Are the codes for drawing SVGs standard? Is there a way to save the gcode to a file, so I could try the output with one of my machines?

Again, well done. Much respect!
-k

Beautiful! Kong is right there's a real lack of a simple g-code tool. Something in between typing g-code yourself and all-singing CNC software. This could be a useful tool for g-code and drawbot experimenters.

This looks great (and finally running in Processing 2 :)), but I have one request: Please change the name of this repo. It isn't a tool for polar graphs, and a polargraph is a specific thing made by me, not a generic term for hanging-V pen plotters.

cheers!
sandy noble

Hey there's an offer I never got! Do you still trail wires (x4) to the pen lift? I guess the speed of the geared steppers isn't so much different to a servo?

Hi, no problem sandy, I have changed the name to PenPlotter here is the new link.

https://github.com/RickMcConney/PenPlotter

I have also added the export. Just load an svg file right click drag to position it relative to the origin and scale it to your liking and then hit export.

The zero position of the exported file is the center home position of the plotter. As the plotter's positive direction is down the page you may get a mirror image if your machine's positive direction is reversed. Also I move +5mm for a pen up and to Z=0 for a pen down. So please check you directions before running on your machine. I may need to add a safe height option to the parameters file if this is a problem.

Rick, thank you! I just plotted a simple drawing on one of my little drum plotters using code generated by your controller. Worked! I needed to update my geomeratrive and controlP5 libraries to the latest (I got a bundle of errors until I did that), but other than that, it was smooth sailing.

There is another issue -- the plot is flipped i̶n̶ ̶b̶o̶t̶h̶ ̶t̶h̶e̶ ̶x̶ ̶a̶n̶d̶ ̶y̶. along the Y axis. I know it's not my machine because the preview in Universal GCode Sender shows the same flipping. This isn't a huge concern for me because I can always flip my art in Inkscape.

Cool stuff!

Yes this is what I mentioned in my comments as the pen plotter has Y down the page but most gcode machines have Y up. I could add a flip Y setting in the properties file. I will look at it more this weekend and see if there is a better way to do it.

Hi, I have added some buttons to flip the plot around the Y or X axis so you can just flip in Y before exporting. I have also added a cnc.safeHeight setting to the properties file so you can change it to what ever is a good height for you. The default is 5mm.

The application launch most likely failed because I forgot to initialize the safeHeight variable when creating the properties file for the first time.
I have fixed that and have added a windows 32 release in the git hub release directory.

If you are not connected to a plotter the plot button lets you step through the plot so you can see what order the paths are plotted in.

I also altered the path optimization routine to pick paths that both start and end near the pen first. I think this should in general give a better path.

Let me know if you find any other issues.

I added an svg.shortestSegment setting in the properties file. I defaulted it to zero so no segments will be removed.

I also added support for drawing images in a cross hatched style similar to blackstripes MK1. This renders a much more detailed image but uses lots of pen lifts, Hope my servo does not give out.

I tried the new version late last night, and did a nice crosshatch drawing on my "toy" drum plotter (it's small and sloppy). This is so exciting!

The issues I've run into, using Processing 3
1. At launch, get following errors:

Use surface.setResizable() instead of frame.setResizable in Processing 3
Use surface.setTitle() instead of frame.setTitle in Processing 3

2. Flipping on the X doesn't work -- console says:

SEVERE: An error occured while forwarding a Controller event, please check your code at mirrorX

and then lists many problems

3. Flipping the Y works (no errors), but does not flip around the image's true center. As a result, part of the image goes out of bounds (of the green frame), and is thrown out (if you flip the Y back, the part of the image that was out of bounds is permanently lost. The lost area is drawn black by the pixel filter).

4. As seen in your crosshatch example, there's always a section (corner?) where the crosshatching fails to get drawn. Sometimes it's kinda' neato the way image starts to fall apart. It's the kind of bug that feels like the code is collaborating artistically.

Thanks again for the fun, Rick.
-k

Plot done on my prototype "toy" drum plotter, using Rick's PenPlotter to generate the gcode: