Original Prototype Parts list

This is the parts list for the original prototype, the newer versions use a custom designed PCB and 3d printed parts, more information is available at gocupi.com

Really you only need 3 main parts, a linux based computer to run the main go command line program, a serial connection to an arduino, and microstepping stepper motor controllers that are controlled from the arduino. Note that to connect a raspberry pi to a 5v arduino you will need a logic level converter. In my build I used a breadboarded arduino running at 3.3v instead of the standard 5v to avoid needing a converter.

Pen Holder / Gondola

• http://www.polargraph.co.uk/setup/polargraphsd-the-gondola/
• http://www.youtube.com/watch?v=ycrGUTGlzik Which is a #144 brass tube
• 6003 bearings
• And some 3mm acrylic that I cut out on a laser cutter

Stepper Motors / Spools

• Spools are aluminum hubs with some acrylic sides
• Stepper motors are 12V 200 steps/rev
• EasyDriver stepper motor drivers
• Stepper motors are connected to the drivers using Cat5 cable and a few rj45 connectors, any cable would work, I just assumed it would be cheapest to use cat5 for long cables

Arduino

• Arduino on the breadboard
• Since it's running at 3.3 volt it is running at 10Mhz
• In order to connect the pi to the arduino and program it I followed the instructions for the Gertboard

Raspberry Pi

• A Raspberry Pi model B
• Adafruit Pi Box
• Ribbon cable to make it easy to connect breadboard to gpio pins