Many technological problems require finding the identity of an object, determining its location, and learning something about its environment. Examples range from ID cards to inventory control to virtual reality interfaces to sensors in hostile environments. While it's possible to solve some of these problems by using conventional RFID techniques (radio-frequency identification chips that are powered by energy remotely coupled in), many of the most interesting applications have the added severe constraints that the tag can cost no more than a penny (so that it can be used on disposable items such as a piece of paper), and the tag must be extremely robust. Since fabricating, packaging, and wiring a silicon chip costs a minimum of about ten of cents, these kinds of tagging problems can not be solved by using conventional circuitry.
Our interest in the Physics and Media Group is to make use of nature's innate
capabilities, rather than rely on complex circuitry. We are studying
techniques to remotely excite and detect resonant structures (from kHz to
GHz), including tanks, cavities, mechanical oscillators, and atomic spins,
that use smart materials to encode identity and sensor information in the
properties of the resonator, and use antennas that can analyze the coupling to
the tag to determine its location. Some examples of these tags are show below.
Position and ID tags (4.8MB MPEG)
Pressure sensitive tag (2.2MB MPEG)
Temperature sensing tag (3.1MB MPEG)
Orientation sensing tag (1.1MB MPEG)
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