Radio Frequency Identification Device
Radio Frequency Identification (RFID), a technology that has been available for several decades, has attracted renewed attention as system costs have dropped, functionality has improved and new applications have been pioneered. RFID systems are not yet used in home building, but they are used for applications such as automobile ignition security and immobilization systems; identification of animals including livestock and pets; automated vehicle toll collection systems; and patron wristbands with "electronic wallets" at theme parks. In Hong Kong, millions of consumers have used an RFID-based electronic cash system since the 1990's to pay mass transit fares and for other retail transactions. Growing interest among retailers has raised the prospect that RFID tags will ultimately replace item-level barcodes for tracking inventory as well as for customer checkout. The power and flexibility of this technology suggest that it will find valuable uses in building product distribution, as well as in housing and the home building process.
Courtesy: Dynasys Technologies, Inc.
Courtesy: Auto-ID Center
RFID is one of a class of "auto-ID" technologies that allow collecting information about a product, place, time or transaction quickly, and without human error. The data link requires no physical contact and can generally be established without any need for line of sight, or concern about harsh or dirty environments that restrict other auto-ID technologies such as bar codes. RFID systems consist of several components, including (1) transponder chips bonded to antennas (see illustration), mounted on substrates and packaged as "tags"; (2) handheld or stationary tag readers and antennas, and (3) input systems for aggregating tag reader data and interfacing to back-end databases or business systems. The tags can be either "passive" or "active." A passive RFID tag is powered either by a magnetic field or a radio signal originating with the tag reader, while an active tag has its own power supply. The tags come in various shapes, sizes and read ranges including thin, flexible "smart labels" which can be laminated between paper or plastic, or mounted with an adhesive backing. Currently available tags and readers operate on frequencies around 135 kHz, 13.56 MHz, 900 MHz and 2.45 GHz. The operating frequency affects the read range (from a few centimeters to as much as 10 meters), the size and design of the tag and reader antennas, the potential sources of interference, and the cost of the reader hardware. Worldwide sales of RFID tags in 2002 were recently estimated at around 300 million units, most of which were passive tags.
The simplest transponder chips used in RFID tags contain small read-only memories (e.g., 64 bits) and are able to broadcast a unique ID code when energized. The analogy to a barcode is straightforward. More complex chips incorporate command sets to support functions such as collision avoidance (two chips broadcasting at the same time). Read-write chips with memories as large as 32 kbits are also available. These are highly versatile because data can be read selectively (in blocks), and can also be updated "on the fly" by the tag reader. The trend is for the newer, more powerful RFID chips to include security features ranging from basic password protection to public key encryption or even Java "virtual machines." These features are designed to prevent forgery, protect privacy and facilitate use in financial transactions.
The unit cost of RFID tags, which has historically ranged from around $1 to $20 (or more) depending on features, has been dropping with increased production, even as their performance improves. Volume pricing of less than $0.50 for passive tags has been reported. These trends have led some observers to predict the emergence of the "nickel tag." Lower tag costs clearly create opportunities for new and innovative applications of RFID technology on a very large scale, although the cost of readers can be high and the systems integration required to make full use of the potential of RFID is sometimes said to be the most expensive piece of all.
Several groups are strong proponents of RFID technology and sources of technical information. One is the industry-sponsored "Auto-ID Center" at the Massachusetts Institute of Technology, a consortium with over 60 members including several very large manufacturers (Coca-Cola, Johnson & Johnson, Kraft, Gillette) and retailers (Wal-Mart, Home Depot). It has sponsored research on topics such as a web-based infrastructure for documenting the properties of any item based on its "Electronic Product Code" (an enhanced version of the UPC) stored in the RFID tag. The goal is to allow users to perform sophisticated processing using the simplest, least expensive tags. Another trade group is AIM (Automatic Identification Manufacturers), the association for the automatic identification and data capture industry. Both groups are working to develop internationally recognized standards for the tags and receivers, since most current system components are proprietary and must be carefully matched to ensure reliability. The Auto-ID Center anticipates publishing a complete standard in the second half of 2003.
Application to PATH Roadmaps
The use of RFID technology is cited as one route to improved supply chain integration and management. RFID tags on pallets or cartons can be used to quickly identify shipments and deliveries. Tags on cartons or individual items can be read to keep track of wholesale or retail inventories, or for rapid point-of-sale transactions. The technology allows quick, accurate reading of large numbers of tags (hundreds per second under favorable conditions), which would be ideal for taking inventory or for point-of-sale checkout. In other words, using RFID tags a receipt could be generated and printed in about the time it takes to push a loaded cart past the reader antenna. "Smart shelves" with embedded tag readers have also been demonstrated, designed to allow retailers to identify out-of-stock conditions and locate misplaced items automatically. Wal-Mart recently announced that it will require its major suppliers to include RFID technology at the pallet level by January 2005. Building product retailers can expect to take part in any broader trend towards supply chain management and automated checkout built on RFID tags. Realizing efficiencies in this way will require significant coordination throughout the supply chain to ensure that items only need to be tagged once, tag readers can handle tags from multiple vendors, and the players share information. Information sharing is essential to achieving efficiencies across firms so that, for example, a supplier can track, aggregate and make plans based on inventory data for multiple customers.
Item-level tagging may ultimately find uses even beyond the end of the supply chain. One vision is the RFID-enabled refrigerator or kitchen cabinet that could evaluate items on hand and automatically generate the shopping list. Tags in clothing could be read automatically by the washing machine to determine proper settings. Tags in food packaging could be read to identify items with expired "freshness dates" or to set time and power level for the microwave. On the building site, individual products could be coded to indicate where in the house they are to be installed. For example, window properties could be optimized for each building wall (e.g., high solar heat gain for south-facing windows, low solar gain for east and west facing window) and the tag could specify where each window is to be installed. Kitchen cabinets could also be tagged for installation in specific positions. Ideally these tags would relate directly to the building plans. Complex structures that are prefabricated in many pieces for jobsite assembly could be similarly tagged. RFID chips with larger memories could potentially contain product installation instructions, material safety data sheets, warranty data, operating instructions or other information.
RFID is also finding uses in ID cards for tracking workers, including access control, timekeeping, and even location within a production facility. It can be used to mark equipment or other assets for loss prevention and control. These capabilities could be used in housing production facilities (modular or manufactured housing) as well as on commercial or other job sites where entry and exit is regulated. In automobile manufacturing, RFID tags of cars or car engines under assembly would document options and specifications for that particular unit and allow recording data along the line as an alternative to paperwork. An electronic "audit trail" documenting the manufacturing process could be created for each product. The same concept could apply in housing plants.
Ignition keys for new cars have used RFID technology for theft deterrence since the mid-1990's. The keys include transponder chips that broadcast an ID code when energized by magnetic coils in the steering column. Even if a new key is cut to fit the lock, it will not operate the vehicle until the on-board electronics is programmed to recognize the ID code broadcast by the new key. Entry locks for houses could use similar technology for enhanced security, or completely keyless entry systems could be used. This would require a power source (e.g., batteries) for the lockset. Prototypes have been produced and displayed by Dialock, a division of Häfele.
One very unusual prototype RFID application relevant to residential HVAC systems was described at a recent trade show. Timely replacement of HVAC filters, though often overlooked, improves system efficiency and prolongs equipment life. This particular application involved an active RFID system that used a sensor to monitor pressure drop across the HVAC filter, and an LED display to alert the occupant when it was time to replace the filter. It represents a simple, self-contained approach that separates the sensor and the display, and is appropriate for homes because it requires no network infrastructure. There is considerable interest in other applications that combine RFID chips and sensor technologies.
The best way to view RFID probably is as an enabling technology that enjoys broad potential application but faces challenges including cost, complexity, the need for security, and concerns about privacy. Although the "killer app" for RFID in homebuilding has yet to emerge, this is clearly an area where technology is expanding rapidly and creative new uses are emerging in unexpected areas. Its ultimate role in housing may simply reflect its applications in other sectors, or it may prove to be uniquely tailored to the industry.
AIM, Inc. (Association of the Automatic Identification and Data Capture Industry)
125 Warrendale-Bayne Road
Warrendale, PA 15086
Phone: (724) 934-4470
Mountain View, CA
Phone: (650) 934-8000
CECOM (Army Communication Electronic Command)
Research and Development Engineering
Fort Monmouth, NJ
Phone: (908) 532-0353
Texas Instruments, Dallas, TX - www.ti-rfid.com
Motorola, Rolling Meadows, IL - www.motorola.com
Intermec, Everett, WA - www.intermec.com
Alien Technology, Morgan Hill, CA - www.alientechnology.com
Philips Semi-conductors, Eindhoven, Netherlands - www.philips.com
SCS, San Diego, CA - www.scs-corp.com
AIM, Inc: Radio Frequency Identification RFID: A basic primer
Auto-ID Center Technology Guide brochure
Auto-ID Center Research Paper Repository
InfoWorld, RFID is About to Explode, January 31, 2003
InformationWeek.com, David M. Ewalt, September 30, 2002