Instructables user [lingib] made a clever and inexpensive pen arm plotter that uses plastic rulers for arms. An inspiring sight for anyone without a bunch of robot parts lying around,
The electronics are straightforward, with an Arduino UNO and a pair of Easy Drivers to control NEMA17 stepper motors connected to robot wheels, which serve as hubs for the rulers. At the end of the arms, an SG90 micro servo raises and lowers the pen as commanded, shoving the whole pen assembly off the paper with its horn—an elegant solution to an age-old drawbot problem. He even wrote wrote a custom Processing program that allows him to control the plotter from his desktop
[lingib]’s experimented with different kinds of drawing machines, including a drum plotter (video after the break), a V-plotter, as well as a rolling drawbot.
You’ll find tons of Hackaday posts about all types of drawing machines, including vintage plotters, plotters for making circuit boards, and even one built out of cardboard.
…the aforementioned drum plotter…
[Thanks, Setvir]
A creative design, but it is awfully wobbly. Not really suitable for anything I’d use a plotter for (drawing a cutting small Pepakura designs).
Perhaps someone more mechanically-inclined could suggest ways to reinforce the arms?
Use closed section tubing. Most wobble in things like this are from twist and flat sections have poor resistance to twist. Even a small diameter will improve torsion resistance. A quick demonstration – tape a paper towel tube and try to twist it. Then slit it from one end to the other and try again.
I like the wobbly look, it means you can plot some incredibly tedious drawing and still claim that you did it by hand. :-)
Perfect for drawing potatoes!
If you want reduced wobble, and are willing to have a reduced print area to get it, consider a pantograph:https://en.wikipedia.org/wiki/File:Pantograph_animation.gif
These designs are great for teaching, and lots of fun. I’ll be recommending this project to my kids as a one worth experimenting with.
Hey, it’s got an Arduino and steppers! Doesn’t that make it a CNC Machine?
All kidding aside, I LOVE the idea behind his lifting mechanism.
The math behind this hurts my head.
I made a digitizer like this using rulers and 2 pots in the commodore 64 days. Cheap and worked surprisingly well.
I think you may have had the same cheap project book I had.
Interesting in it’s simplicity.
I made a set of robot arms for a science Olympiad competition years ago using yardsticks from Lowes. Great prototyping material. Exactly the right width for mounting a metal geared servo in there.
Not taking away from the achievement of producing a working plotter, the arms are going to be the lowest cost items as compared to the controllers, drivers and power supplies – so why use 4 wobbly rulers rather than a single piece of hardwood beading from a DIY store for about the same price?