I recall reading an article about 10 years ago describing a PARC research project in which networked computers with antennae were placed throughout a set of rooms, and the subject carried a small transmitter with them from room to room. As the computer in each room detected the transmitter, it triggered actions in each room. I think it was called "ambient computing."
Does this ring a bell for you? I have searched for this article recently and not been able to find it again.
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