Unicorn Mk1 Usage



The Unicorn is a far different toolhead from either the Frostruder or Plastruder. Instead of extruding material, it holds and actuates standard drawing implements to quickly and precisely plot out a two dimensional image/vector file.

The Unicorn is usable with hundreds of drawing implements. Go crazy: try paint brushes, huge markers, scribes, swivel x-acto knives and whatever else you can think of. The Unicorn turns your Makerbot into a platform for 2D experimentation.

Aside from drawing awesome images, it can also draw PCB designs onto copper boards which can then be etched to create custom circuit boards quickly and easily.

Because there are so many opportunities yet untapped in the 2D plotting world, there's tons of room for development. We welcome your feedback and if you come up with better scripts, tips, and tricks please share them back with the community.


The Unicorn's software tools are derived primarily from the Frostruder-Tool-Sweet-0001 but have a few major changes and some very cool additions. You can download the Unicorn Tools from GitHub. Just click the "Download Source" button in the upper right to get the compete package, including code and example files.

There are two python scripts that have been adapted for the Unicorn and a totally new one that is pure awesome:

  • scribbles.py - the quintessential Unicorn script converts a DXF file into a plot-able gcode file. Scribbles.py is derived from Lunchlines.py but has been given a few touch-ups including the removal of all unnecessary pauses and pen lifts so it's super clean and speedy.
  • plotterize.py - convert an image (gif, png, jpeg, etc.) into a plot-able gcode file.
  • gerbertogcode.py - plot PCB designs straight out of Eagle or other CAD programs and onto copper boards to create your very own custom circuit boards quickly and easily.

In order to run these scripts, you will need Python and the Python Imaging Library installed. On ubuntu, you can install it like this:

apt-get install python python-imaging

Note: I've found PIL to be a little tricky to install on Mac OSX. This is the best link I've found (the download link is on the right): http://effbot.org/zone/pil-index.htm


Installing your drawing implement


Attaching your pen/brush/marker to the Unicorn really couldn't be simpler. Unscrew the thumbscrew on the front until you can slide your pen in from the top. I like to leave about 20mm of space between the tip of the pen and the bottom of the pen carriage but precision here really isn't necessary. Once your pen is in a good location just tighten the thumbscrew down until it's sturdy (not so tight that you destroy the pen but enough so that it won't slide up when it's drawing).

Configure ReplicatorG

You must use ReplicatorG 0019 or later and the latest firmware version for the Unicorn to function properly.

Test your axes

Now you should make sure that your axes are moving in the right directions. Move your X-axis in the positive direction with the control panel. It should move to the left. Move your Y-axis in the positive direction now. It should move toward you. In other words, the bottom left corner of your build platform can be considered (0,0) and the top right corner is (100,100).

You're almost ready to go. Now there's just a little bit of g-code between you and masterful robot-made drawings.

Usage / Toolchains

There are a many different ways that you can use to create toolpaths for plotting. There are two main formats for creating art, and there are tools for both. There's also a nifty script that will allow you to plot circuit boards designs.

2D Vectors -> GCode

Scribbles.py will take your 2D vector image (DXF or SVG) and convert it to g-code to use with the Unicorn. Scribbles.py is derived from the lunchlines.py script for the Frostruder but it's been upgraded to be quicker and cleaner.

Jump to the scribbles.py page for detailed info on how to use the script.

2D Bitmap -> GCode

Plotterize.py will take your 2D bitmap, convert it to a black and white image and then generate a printable gcode file that will replicate your image using the Unicorn. This output is similar to very old printers. Retro-unicorn-action!

Jump to the plotterize.py page for detailed info on how to use the script.

PCB Design -> GCode

We have created a new script called gerbertogcode.py. This script will take your Gerber file (exported from Eagle or other PCB CAD program) and convert it, line by line, into G-code that the Makerbot can understand. Then, using an extra fine point sharpie you can draw circuit designs on copper clad board and etch your own PCB's!

Jump to the gerbertogcode.py page for detailed info on how to use the script.

Unless otherwise stated, the content of this page is licensed under GNU Free Documentation License.