The setup is ready to test! The software you use to control it is a little application written in Processing. You can run this from the source code, but it's probably easier to use one of the pre-compiled binaries that I've made. The most recent code bundle has the latest versions for Mac, Windows or linux. Download the file called Polargraph.*.zip (rather than the "source code" files).
(That bundle also includes all the source for the controller, and the firmware, and all the Processing and Arduino libraries you need to run from source.)
Download it, unzip it, and run the executable in the controller folder. It'll open up very small, but maximise the window to see more. It will automatically create a default configuration file in the same folder as it runs in, and you should then click "save properties" in the top-left corner to save the new window size as the default.
Compile from source
If you're curious about Processing, you're right to be: It's ace. There are useful tutorials on processing.org, and of course here on Instructables too. It's basically java, but optimised to run little stand alone programs with graphics. If you're interested in keeping on the leading edge of the controller development, you might like to check out the code directly from the repository and compile it yourself. Another reason: The precompiled binaries that I distribute are a little idiosyncratic, and sometimes refuse to work on some people's machines. If you compile from source, then it'll work at least.
Couple of notes - The controller is getting a bit long-in-the-tooth now, and I haven't updated it to use Processing 3 yet. So in the meantime, it will only compile in Processing 2.x. Additionally, the libraries have also since moved on since it was written, and it'll only work with the versions in the zip file (referred to above). I'm working on an update, but it's not ready yet.
- Install Processing 2.2.1 (From https://processing.org/download/?processing)
- Run Processing, find where your sketchbook folder is: (File->Preferences, sketchbook location).
- Install libaries: Unzip the code bundle, and copy the contents of the processing-source/Processing libraries into sketchbook/libraries.
- Install project: In the code bundle, copy the whole processing-source/polargraphcontroller folder into your sketchbook folder.
- Restart Processing, and open the controller with File->Sketchbook->polargraphcontroller.
- Run: When some files have opened up and you can see some code, hit the play button in the toolbar (or use Ctrl-R) and you should see the controller spring into live.
It'll only be a small window, so go ahead and maximise it, or stretch it so you can see everything. If it worked, then well done. NEXT!