Stokes' ProjBlog

Junk Box DrawBot June 13, 2013

Someone in the Introduction to Arduino class I teach at Artisan’s Asylum asked me what could he actually do with the knowledge and materials I supply. As an answer, I built a robot, using materials from class and random parts in my junk box.

It took maybe 90 minutes to construct, nearly half of which was simply rooting around for just the right part. I might have done it in less time if I’d used proper tools; all I used was a power drill, a nibbling tool, and a needle file, things I had readily available at home.


The electronics — LEDs and L293D H-Bridge chip — were the same as the ones I passed out in class. I gave each student only one motor, whereas this ‘bot uses two, so technically speaking, I suppose a student would need materials beyond what I supplied. Two students working together could easily build such a robot, however, so I figured that was a fair compromise.

Just so the robot would actually do something, I added a holder for a Sharpie marker. I wrote a couple of simple Arduino sketches to generate pen-and-ink sketches, each taking only a few minutes to create. Most of them produced ugly results. My final sketch drew spirals by using a sine wave to slowly change motor speed. None of the Arduino sketches were worthy of showing off, however.

I thought of adding some additional features, such as a pen-lifting mechanism and encoders on the wheels, but that started to expand beyond the original goal: demonstrating what could be done with just the stuff I provide in class. The DrawBot version 1 was easy enough to build, however, that maybe I’ll just construct a second, more advanced one later.