So, after a lot of trying to mess about with RSS and make listening for tweets work without a separate computer feeding into the Arduino I have sadly resigned to the fact it isn’t going to happen. No library I can find supports actually checking a twitter stream, and for posting images to Twitter I have found only one somewhat lacking in documentation library.
These things however are quite frequently worked around by interfacing Arduino with Processing. As this project is intended to be able to be left on dedicating a laptop to it seemed like a bad idea. Simple I thought, I will use the good ol’ Raspberry Pi! I was not as right as I could have been, out of the box Processing is unable to run on the Pi. You have to mess about with Java to get it working. Happily this lovely person has it all worked out: http://scruss.com/blog/2014/01/07/processing-2-1-oracle-java-raspberry-pi-serial-arduino-%E2%98%BA/ Not only do the explain how to exchange the Java packaged with Processing to the new Hard-Float Java 7 which is supported by the Pi, it also gets serial up and working (which is one way of interfacing between the Adruino and Processing).
Processing actually runs fairly reasonably on the Pi, I found 2.1 was much more reasonable in speed than 2.1.1. I suspect if I were doing much intensively this wouldn’t be an option but to send and receive data to the Arduino it seems like a viable option.