TL;DR: I made a plotter that uses rotations to draw, and it’s hypnotic to watch.

So recently I imagined an interesting way for a robot to draw images. Typically drawing robots (sometimes called “plotters”) use two axes, one for horizontal and one for vertical to draw an image on a paper. While this works, and is very straight forward I had something else in mind. Instead of moving linearly across the page, why not rotate the page and adjust the radius of the pen? And instead of linearly adjusting the radius, why not have the pen on an arm that rotates? It’s hard to explain, so check the video below.

The basic idea, though, is that it would work like a hard drive head: an arm holding a sharpie would sweep across a disc that’s rotating. If we control the arm and the disc, any picture is possible, including square lines and such. I’m sure I’m not the first person to think of this, but I thought it would be fun to build and a fun mathematical challenge to solve.

Because I didn’t want to spend money on hardware right away I decided to write a simulation instead. I had to use lots of trig to get it working, and it definitely took a few days to wrap my head around, but I finally got it! The program is pretty simple, you just doodle a drawing on a canvas, then the robot attempts to draw the drawing using virtual stepper motors. Check the video below to see the simulation in action. The rotational drawing is hypnotizing to watch!

Here’s a quick video of a straight-line test:

Note: I’ll eventually make the source available and the program downloadable after I clean up the source and polish a few rough edges.

August 31, 2014 at 9:09 am | Code Projects, Video