ZigBee: ZigBee is a relatively new standard for wireless communications. It allows the tags and receivers to automatically form a “mesh” of communications, in which tags can talk to other tags as well as receivers. The advantages are significant in that if a tag cannot see a receiver, it can still send a signal to it by passing through another nearby tag. Beyond reliability, this has the effect of dramatically reducing installed cost, since fewer receivers are required and placement and installation is less critical. In fact, the receivers are often just plugged in to outlets in each room.
While location is often determined computationally using signal strength, it is possible for the system to periodically calibrate itself by measuring the signal between each receiver. This can result in good positional accuracy and resilience to changes in the environment. Because ZigBee was designed with battery operation in mind, battery life is also good. For an example of a ZigBee system, see Awarepoint (www.awarepoint.com).
All of the above systems are “active” systems. That means the tags contain a battery which provides the power for long-distance communication, and, in some cases, assisting to compute location. Of course, the downside of this is cost, size and maintenance headaches. The other option has been passive systems. The best-known example of this technology in the security would be our proximity ID badges, where the reader on the door sends power to the tag in the badge and no batteries are required. The downside historically has been very short read distances in a passive system.
This is changing, however. Over the last year, tags and handheld readers have emerged for retail and supply chain applications that can read up to 40 feet away. Called “UHF Gen2” technology, they are part of a large project to replace printed barcodes on all retail packaging with an RFID device. They are already priced well under a dollar and are headed much lower as volume grows.
Even with this tempting price, however, no one thought there was any possibility of doing RTLS applications with them over any great distance. That was until a company called Mojix (www.mojix.com) demonstrated a reader system last year that could read these tags at 300 feet away and has the technology to locate the tags within a 3-foot radius. They claim the reader will be specified to a 600-foot distance. This will be a great system for the retail environment with the potential for inventory and loss prevention in one.
Are We Ready?
Is it time for security to think about asset management again? It’s still not an easy decision — there are lots of choices, and while costs have dropped, they still can be tough to justify. The good news is there are also a large number of system choices now available which makes finding the right system for your needs more likely. If your company could benefit from the operational efficiencies of asset location, you could easily find that today’s technology could be just what you need.
Rich Anderson is the president of Phare Consulting, a firm providing technology and growth strategies for the security industry. A 25-year veteran of high tech electronics, Mr. Anderson previously served as the VP of Marketing for GE Security and the VP of Engineering for CASI-RUSCO. He can be reached at firstname.lastname@example.org.