[chiplotle-discuss] Plotter Tinkerings

Brian Boucheron brian at boucheron.org
Mon Nov 7 12:29:03 EST 2011

Hi all,

I don't think I posted to the list about this, but apologies if I'm
dupe-ing myself. I've been doing some tinkering with chiplotle ever
since I got my behemoth DPX-3300 a few months back, and I have a
little code and a few pictures/movies to share.

First off, I started by figuring out how to patch together enough
tools to get webcam input automatically traced and sent out to the
plotter. This involves some OpenCV, autotrace, and pstoedit (as
discussed here on the list previously). You can find that code here:


It's in a bit of a clunky state, to be honest, but it'll be a good
start for anybody looking to noodle around with this stuff.

I was a bit dissatisfied with the path my plotter was using to draw...
it was a very inefficient top down path with lots of seeking back and
forth. I assume it was based just on how the EPS file was constructed.
So I made a really naive sort routine that basically slurps in an hpgl
file, strips everything down to a simple group of paths, and then
sorts so that at the end of a line segment, it looks for the next
nearest line and goes there. That code, along with some other silly
stuff, is here:


And you can see some time-lapse video of the difference at the end of
this post (and in the chiplotle group on flickr):


Finally, I wanted a neat drawing bot to show off at the local BarCamp
here in Rochester, but I didn't want to lug my 110 pound plotter
around, so I built a junkbot plotter that draws on 4x3 inch tractor
feed cardstock. It uses mostly the same toolchain mentioned above, but
spits out some ugly gcode at the end to send to an arduino running
grbl  ( https://github.com/simen/grbl ), which turns the gcode into
steps and pen up/down movements. It turned out pretty neat, and there
are pictures and video here:


So that's what I've been doing for a few months. Has anybody else been
tinkering with chiplotle and plotters lately?


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