I found some old photo scanners for free on craigslist so I thought I’d turn them into a plotter. I used an old microcontroller I had laying around to control the stepper motors and servo for the pen along with a bipolar stepper driver I got off sparkfun.com.

This is a video of the plotter drawing a sine wave. It was amazing being able to move the pen across the page and move it exactly back to where it started with such little effort. One scanner is pretty old and could only achieve 1200 steps per inch while the other is only a few years old and gets 5000 steps per inch.