Steel, liquids, animals and people, among other things, can disrupt RFID (radio frequency identification), according to Visible Assets, the small company that developed RuBee. Visible Assets sponsored the development of the new IEEE 1902.1 standard along with Seiko Epson, one of its licensees. It took about three years to complete the specification, according to Visible Assets CEO John Stevens.
RuBee gets around some of the limitations of RFID by using magnetic or "inductive" waves rather than radio waves and using very long wavelengths, Stevens said. In addition, RuBee tags can both send and receive signals, unlike RFID tags, which can only be passively read by scanners, he said. That means RuBee tags can either communicate with a base station or form a peer-to-peer network. RuBee is a packet network protocol like Wi-Fi or ZigBee, according to Stevens.
RFID is used to identify and gather information about objects and people for shipping, asset management, security and other applications. RuBee can serve much the same purpose, but in conditions that hamper RFID, according to Visible Assets. For example, a RuBee tag can be built into a gun and send data through its steel body. That allows a base station at an armory to collect information about how many times the gun was fired while it was in the field, Stevens said. The same base station and tags can be used to keep track of which guns are in the armory at a given time, he said.
Another promising area for RuBee is in health care, where it can be used to track both patients and equipment around a medical facility, Stevens said. One company is using the technology to tag wine bottles. RuBee, which does not rely on line-of-sight communication, has also been used for livestock, parts and tool tracking. One set of base stations and tags can be used to track employees, tools and parts simultaneously, he said.
"RFID has given up on almost every application we're in," Stevens said.
Steel and other materials can block RFID signals and "detune" RFID antennas, preventing them from using the frequency they are supposed to use, according to Stevens. RuBee signals can go through steel, water and other materials because they use very long wavelengths with "near-field" communication, he said.
RuBee uses frequencies in the kilohertz range, far below those typically used for radio communications, where it's easier to use magnetic than radio signals, Stevens said. The wavelengths used in a typical RuBee network are about 1.5 miles (2.4 kilometers) long, while the wireless links between tags and base stations typically span less than 50 feet. With less than one wavelength between the elements of the network, the signals can penetrate materials more easily.
Another advantage of low frequencies and long wavelengths is low power consumption, according to Visible Assets. RuBee tags have been proven in the field to last several years on one coin-sized lithium battery, the company said.
Visible Networks, founded in 2002 and based in Chatham, New Hampshire, makes its own RuBee chips and licenses the technology to other vendors. Epson Seiko makes RuBee tags, and gunmaker Sig Sauer builds tags into guns for use with tracking systems. Visible's chips range in price from a few dollars to more than US$100, depending on how specialized they are, Stevens said. The company has demonstrated RuBee with steel and water in a YouTube .
The company licenses RuBee technology on a fair, reasonable and non-discriminatory basis, as required for IEEE standards, Stevens said. He expects the completion of the standard to expand the RuBee market. Most countries afford a wide latitude for use of the bands where RuBee operates, he said.