Step 8: Electronics - Arduino
Upload the source code to the arduino. Look at this fine guide courtesy of Adafruit for help.
Because it changes regularly, I have not attached a copy of the code itself to this step, but the very most recent version can be downloaded in a bundle from the polargraph code repository - in a zip called polargraph<version number>.zip.
You should save the code file into a new folder inside your arduino sketch folder. Give the new folder the same name as the source code file. So if the file is called polargraph_server_a1.ino, you should create a new folder called polargraph_server_a1 and save the file into it.
It also uses Adafruit's AFMotor library and Mike McCauley's Accelstepper libraries. Please use the copy of Accelstepper that is in the zip file - the newest versions of it have a few fixes in them that the polargraph code isn't yet updated for.
The AFMotor library files should be put into a folder called AFMotor inside your Arduino/libraries/ folder.
The Accelstepper library files should be put into a folder called AccelStepper inside your Arduino/libraries/ folder.
Once they are moved, your arduino installation directory should look something like the second image on this page.
Of course the source code is also available in the code repository - https://github.com/euphy - should you want the very most recent version.
Once you do that, you should confirm that it is working properly - use the serial monitor on the board, set to 57600 baud to make sure that it is issuing "READY" every couple of seconds (see the third image).