A great site detailing the limits of data capturing with an Arduino - https://sites.google.com/site/measuringstuff/home
The arduino board can be accessed solely through text based Javascript coding (provided the Arduino is running Firmata ), and I recommend this for debugging purposes often, especially to test that your overall setup is working. A number of good examples exist of this approach, with the following recommended:
Begin with the classic 'hello world' of hardware, namely making an LED on a breadboard and thereafter get acquainted with the code.
If you've never run a Javascript file in your life before (as I had when I started this project, visit Setting up node.js where I describe it for the complete beginner).