Comment by RickS

This is great. There's a project that's the inverse as well: http://www.quantumpicture.com/Flo_Control/flo_control.htm

A door that only lets cats in, based on image recognition.

As an aside, I've really enjoyed the particle photon so far. It was a little wonky at first when they didn't have persistent storage of state changes, but now that's up and running, it's flawless. It runs the lights in my house (via a relay just like OP) and has recovered from a few power outages with no attention necessary from me.