A programmer named ioan ghip has two cats Gus and Penny. Gus and Penny are indoor /outdoor cats. The cats' food is left for them in the garage, but, since the neighborhood cats noticed that the food Gus and Penny get is better than theirs, well, the food started disappearing at an alarming rate. ioan ghip decided to solve the problem with technology. First he modified the cat door. Then he added small RFID tags to Gus and Penny's collars. The tags send out low-level radio signals; these are the same kinds of tags to prevent shoplifting. When Gus or Penny approach the door, an RFID reader connected to an old laptop "sees" the signals from their collars, and a servo on the door opens the door to let them in. A cat without a tag on its collar, or a tag that the computer hasn't been told to authorize, can't get in.

But because ioan is a programmer, he had to go above and beyond the efficient, and add the "coolness" factor. If you pay much attention at all to the Web, you've probably read about, or use, or know someone who uses Twitter. It's a Web based service that sort of combines texting or "instant messages," with blogging. People get a free Twitter account and can then send short messages that are 140 characters or less to the Web. Their friends (and the general public) can "follow" them on Twitter, and respond. You can even send images to Twitter, from a laptop or a cell phone.

Every time Gus or Penny approach the door, so that a "cat event" takes places, the old laptop sends a Twitter text message, and a snapshot of Gus or Penny to the Web. You can read the details here, and you can follow Gus and Penny on Twitter.