Polargraph - Parts and Instructions

I am going to say that I am just basing my work on that of others - these are just what I did with the existing information and models.

I followed this tutorial for my entire assembly, adapting where it made sense - http://www.instructables.com/id/Polargraph-Drawing-Machine/

Also this site for more information and up to date software http://www.polargraph.co.uk/

I am using two nema 17 motors from Adafruit. The motors are run with an arduino Uno and adafruit v1 motorshield (I had this just laying around, it turns out that it works perfect with the 'firmware' for the bot). I have a 12v 1.5a power supply running the motor shield and I have isolated (through removal of the jumper on the board) it from the Uno which is getting power and information from my PC. Two 6' 3.5mm ball chains are being used as both gears and pulleys for the system - these work great for this project.

I flashed the 'firmware' from this github https://github.com/euphy/polargraphcontroller/relea