In my search for up-to-date tutorials on connecting sensors to Processing I found a few valuable threads.
They are clear, the code is GPL, the aesthetics are – well I guess not my taste – but opinions are very easy to get by – good tutorials – less easy to find (=a critical compliment). Jeremy goes a step further than the usual Hello World “Blink a led sketch”. I didn’t do what he does at 20 years old.
He starts with an introduction to Arduino:
Found through the use of a search engine and this blogpost.