There is a good chance you have never heard of Radio Frequency Identification (RFID), but there is every likelihood that you have used it on more than one occasion. Whether it is through a name tag that allows a person to enter a secure part of a building, or a device that monitors library books, RFID has become very much a part of modern society.
The concept was first employed in military aircraft and had a single purpose—to broadcast a signal indicating if it was a friendly aircraft or an enemy. A similar rudimentary device was also in use in the security industry, to determine if an object being protected was indeed where it was supposed to be. Mario Cardullo was aware of both systems in 1969, when a chance meeting with an engineer lamenting the difficulties of using bar codes to track railroads caused him to advance RFID dramatically.
What Cardullo actually conceptualized was a relatively simple device. He conceived of an RFID that would consist of some form of tag that could be read electromagnetically by a reader. One of the earliest applications was in an unmanned toll booth for the New York Port Authority. At about the same time, a competing inventor, Charles Walton, figured out how to make a door lock that could be opened only when a certain radio frequency was broadcast—in other words a door opened by a key card.
Current applications have also expanded to fill a significant retail need. Although the bar code remains the gold standard for identification on inventory at present, RFID devices are in development and may supplant them, given enough time. RFIDs are already being implanted into household pets as a way to track them when lost.
