Typewriter??

There's many more, like a lot of the clothes, or for instance when they are in the tavern you can hear in the background the commentary for a soccer match (in Italian), presumably coming from a TV.
I think it is about the things which never change; I find it was beautifully done. Young caravaggio wears a mod jacket at some point, and the calculator, for instance, you can think of it as a symbol of that person being valuing art only in a monetary sense.
So then, why not use an abacus and proper renaissance clothes, and all the paraphernalia? Because the movie is not really about the 17th century, much like Caravaggio was an outsider to his era. Likewise this is how Jarman possibly felt about this time that we live in. But that is just my take :)