How have I missed this? Apologies. Being unfamiliar with programming, I tend to glaze over a bit when articles start to detail exactly how their software components work. And increasingly these articles have been on about Arduino, which i took to be none of my business. But it is in fact a lot my business! Its that elusive link between Processing and tangible interaction, to paraphrase.
Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It's intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments.