Michael Fogleman

The AxiDraw is a very nice modern pen plotter. It ships with Inkscape-based software for controlling it, but I was more interested in programmatically controlling it myself. So I wrote this library that controls the plotter directly over the USB serial port.

The most interesting part of this project, for me, was writing my own motion planning algorithm. I stuck with constant-acceleration for simplicity, and the code for the planner came out to just a couple hundred lines of Python!

See the motion planning algorithm in action in this web-based visualization.

Features

• control the AxiDraw directly from Python with a simple API
• convenient command-line utility
• constant acceleration (trapezoidal velocity) motion planning
• path drawing order optimization
• drawing transformations
• preview drawing (render to png)
• turtle graphics
• lindenmayer systems

This code interfaces with a USB GPS receiver and produces a 3D visualization of GPS satellite positions for all of the satellites that are currently in view.