Clipboard Plotters

I set out to build a CNC plotter with the following specifications: it has to be able to operate while carrying it, and it has to be as cheap as possible. These two little machines are the result, tiny and portable plotters built onto clipboards with around $33 and $49 in parts, respectively.

They are not high-performance or a super reliable workhorses, but they were not meant to be. For motors, I chose to use 28BYJ-48 uni-polar stepper motors. They are common and inexpensive. However, in the CoreXY configuration, they barely have the torque required. Generic linear rails with more traditional cartesian kinematics are a bit pricier, but more effective.

For pen lifting, I used a common 9g micro servo. It works fine for the purpose.

On the electronics side, I used an Arduino Nano and Darlington array uni-polar stepper driver boards (commonly shipped with the 28BYJ-48 stepper motors). You can find wiring diagrams for a very similar setup using an Arduino Uno online. The Nano is running a modified version of GRBL, based on this fork. I recommend using a standard Arduino Uno, as the Nano's usable flash space is a bit too small for GRBL with CoreXY kinematics enabled, requiring the removal of some unused GRBL functions. The Nano is powered over USB by a computer, and the steppers and servo require additional 5V power, provided through another USB cable.

I use my Patherator software to generate G-Code for it. Inkscape with a G-Code plugin would work well too, and is easier to install if you don't want to mess around running Python scripts.

To run the plotter on the go, I send G-Code to it with my PocketCHIP running a simple serial sending script, and a common cellphone powerbank provides power for the motors.