Building a polargraph plotter. Part 2: testing, machine control and iteration

This is a group project with Paul and Sophie. Our group docs are here.

Testing our first prototypes

Before we tried controlling the Penguino with a computer, we tried moving the gears by hand. We tried tracing a simple drawing. We quickly learned that our gondola was not stable enough, and that there was a lot of slop in the chains, which we swinging back and forward. Our temporary drawing surface (corrugated card) also proved to be too flimsy.

So while Paul got to work on the machine control code, I worked on a redesigned version of the gondola.

Gondola version 2

I wanted to make a gondola with a flat acrylic base, to aid smooth movement over the drawing surface. I used some existing PVC pipe (lined with closed cell foam) to hold the pen, and laser-cut the other parts to fit.

I used 1-part cast acrylic bonder to glue the parts together.

We quickly found that the gondola needed more weight to keep the pen stable on the paper, so hacked a quick fix by taping bolts to the acrylic base.

By this time, Paul had some control software working, so we able to try some computer-controlled test drawings.

Gondola version 3

I wasn’t happy about the weight hack, so made another version of the gondola that could have bolts attached or removed as needed.

I made all the parts out of clear acrylic, so we could get a better view of the drawing in progress.

Then we tried some more test prints. For these, we also made a more substantial bed for the drawing paper, to provide a rigid, stable drawing surface.

Video of the Penguino in action