Spiegel calls this Pet Door 2.0

Ghip happens to know such precise details about his cats’ behavior because he has figured out how to make the world’s first photo-tweeting cat door. Penny and Gus both wear collars outfitted with thumb-nail-sized radio-frequency identification (RFID) chips. The chips are passively sensed, which means they don’t require a battery and don’t weigh down the collar. Whenever a cat goes near the door, a small RFID reader scans the tag and determines whether the cat is authorized to go in or out.

If the chip tells the reader that the cat is authorized, it not only activates the door opener; it simultaneously also activates a camera and a program on an attached laptop that sends the captured image to a separate Twitter account, where it is automatically posted on the cats’ microblog with a simple, cute caption that is automatically generated, such as “Gus is out to get rid of a hairball” or “Penny is in to shred the chair.”

Very nice. I first wrote about this idea in October 2005 on Bruce’s blog