IF YOU like a bit of high-tech fun while you’re out shopping, there are few better places to visit than the Prada store in SoHo, Manhattan. Pick a suit from the rails, step into the glass cubicle that serves as a changing room and the walls automatically turn opaque. Hang your suit on a hook and an LCD screen spontaneously lights up. It will tell you about the fabric the suit is made from, show you design sketches and pictures from the catwalk, tell you the other colours it comes in and which accessories to match it with.
How does the screen know what information to display? Simple. The suit carries a smart electronic label which shouts its identity to a reader embedded in the hook. The reader then contacts a central computer which sends the information to the screen.
The suit’s smart label is what’s known as a radio frequency identification tag – a transponder just clever enough to know its own name. As gadgets go, RFID tags are fairly humdrum. But thanks to a couple of technological breakthroughs, they are poised to move out of relative obscurity and become one of the most ubiquitous technologies in the world. Soon, every single manufactured item, from milk cartons to consumer electronics, will carry a tag.
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Just like the bar codes they’ll replace, RFID tags are principally there as an identifying mark. But the way they do their job leaves bar codes in the dust. The tags can be read from several metres away, at any angle and without being scanned manually. That means RFID tags are always on, ready to broadcast their identity to any reader within earshot. Set up a network of readers and you can automatically keep track of anything carrying a tag. Connect those readers to the Internet and you can keep tabs on anything, any time, finding out not just what it is but where it is too.
The first users of this “Internet of things” are likely to be manufacturers, distributors and retailers. Hardly a prospect to get pulses racing, admittedly, but a vital stepping stone. By installing readers throughout their supply chains – in factories, warehouses, lorries and supermarkets – they will be able to keep a constant eye on their stock. Soon you will be routinely carrying RFID tags home in your shopping bags. And then it will make sense to put readers in your house – in the fridge, say, to keep stock of your groceries. One day you could even keep track of personal items such as your wallet or keys this way.
A typical RFID tag consists of a microchip with a copper radio antenna spiralling round it like the coil of an electric hotplate (see Diagram). Chip and antenna are mounted on a flexible plastic square to produce a thin, flat tag that can be stuck on anything. The microchip can store up to 2 kilobytes of data, enough for a unique identifying code and a little more, in a modified type of read-only memory (ROM). The antenna enables the chip to broadcast this information to a reader when prompted by a radio signal. The tag doesn’t need its own power supply, as it can scavenge enough from the interrogation pulse to send its data back.
Who goes there?
The idea was first used by the Allies in the Second World War. The “identification friend or foe” system used bulky, high-powered transponders to identify incoming aircraft. Tags have since found their way into all sorts of places. Their most common use today is in the electronic cards that control access to offices. Airports also use them to keep track of baggage, and electronic tollbooths rely on them to automatically charge motorists for using a stretch of road. Museums use them to keep tabs on valuable paintings. Many cat and dog owners have them injected under their pets’ skin to identify them if they get lost, and a family in Florida, dubbed “the Chipsons”, have even had themselves implanted with tags to give medics direct access to their records.
The list goes on. But there are two things holding today’s RFID tags back. The first is that different manufacturers use different standards, so tags from one don’t register on another’s readers, and vice versa. Integrating all of them into a single system will be like building an electronic Tower of Babel. The second problem is cost. Tags cost 40 to 50 cents each and readers cost $1000 or more. So while it makes sense to stick a tag on a Rembrandt, it isn’t yet worth putting them on everything.
Not for much longer, however. At the Auto-ID Center, an industry-backed organisation jointly based at MIT in the US and the universities of Cambridge in England and Adelaide in Australia, teams of academics are tackling the standards problem. Meanwhile, a small company in Silicon Valley looks to have slashed the cost.
The Auto-ID Center won’t manufacture RFID tags and readers itself, but is developing standard specifications for their hardware and software. Companies such as Texas Instruments that already manufacture RFID systems are watching with interest.
At the heart of Auto-ID’s plan is an unique identifying number for each chip – a 96-bit electronic product code (ePC) that makes every tag different. The ePC is split into four sections. First comes an 8-bit prefix that identifies the type of ePC. Next is a 28-bit number that identifies the manufacturer of the product the tag is stuck to. The third part is a 24-bit number that identifies what the product is, say a bottle of Chardonnay. Last comes a 36-bit number that uniquely refers to that bottle and that bottle alone.
When a tag is interrogated by a reader, it sends back its ePC. The reader then feeds this code to a computer running a piece of software called a savant. The savant looks up the ePC, via a network connection, in a database called the object name service, which in turn locates an Internet address where information about the product is stored.
The 96-bit standard gives RFID tags an awesome capacity for information. “With 54 bits you can number every grain of rice produced in the world,” explains Sanjay Sarma, co-founder of the Auto-ID Center. “With 138 bits you can number every molecule on the surface of the planet.” A 96-bit ePC allows for 268 million different companies, each with 16 million product lines containing 68 billion individual items.
So what about making the system commercially viable? Auto-ID says a realistic target for the tag readers is $100. Chips, meanwhile, will have to cost less than 5 cents apiece to make it worth sticking them everywhere. Enter Alien Technology, a start-up in Silicon Valley that is sponsoring the Auto-ID Center and promises to bring the cost of RFID down to earth.
Cheap and cheerful
Alien produces the memory chip at the heart of the RFID tag and it’s here that they can make huge savings. Chips are currently cut with a diamond saw from 20-square-centimetre silicon wafers, each yielding approximately 15,000 microchips that cost about 40 to 50 cents apiece. Alien, in contrast, uses a process called wet etching in which thin lines of acid eat through the wafer. This method can yield up to 250,000 chips from the same size of wafer, making each chip considerably cheaper. Alien has already produced working chips that are 850 micrometres wide. Its aim is to shrink the chips to under 400 micrometres – about five times the width of a human hair.
But making small chips is only half the problem. Manufacturers have known about wet etching for years, but the robots that attach the antennas cannot yet handle the tiny chips that result. “The limits of silicon design have not been explored to any extremes yet,” says Tom Pounds of Alien, holding a vial of dust-like chips. The challenge with shrinking chips is not the electronic circuitry, he says – it’s being able to handle them.
Alien may have solved the problem with a process called “fluidic self-assembly”. It starts with something like a snow shaker. Alien suspends millions of chips in fluid, then passes the mixture over a plastic sheet perforated with holes the same size as the chips. Chips from the fluid fall perfectly into place, filling most of the holes. The ones left over are then recycled. It saves a robot having to pick and place chips individually. The end product is a flexible, chip-studded sheet that can be fitted with antennas and cut into individual tags. The process allows Alien to produce 200,000 tags per hour, compared with the 10,000 or so possible with conventional methods.
The company will deliver its first batch of RFID tags to the Auto-ID Center at the end of this year. The first batch will cost about 20 cents each. Alien believes it will be able to break the 5-cent barrier by 2005. Eventually it aims to churn out over 80 billion chips a year – that’s more than the number of RFIDchips of any kind currently in existence.
Back in the everyday world, here’s how the tags might work. Imagine you go to the supermarket and stack your trolley full of tagged items. When you reach the checkout a reader automatically scans the tags on your groceries. To prevent all the tags responding at once with a cacophony of confusing information, the reader speaks to each tag in turn. It basically says, “If your ePC begins with 0 respond now.” If more than one chip responds, it asks for those beginning with 00 and so on. It can read 50 tags per second, and in no time it has totted up your bill. One swipe of your debit card and you’re on your way.
Behind the scenes, the supply chain responds. The supermarket knows what you bought and updates its inventory, in turn prompting its reordering system to restock. This message filters all the way back down to the factory floor. The all-seeing system will then track goods in transit from the warehouse, as well as preventing the waste of an estimated 20 per cent of perishable goods left to rot in warehouses every year. The tags will also help prevent theft, and aid the recall of faulty goods by identifying where they are.
Meanwhile, you arrive home and fill your reader-enabled fridge. It immediately reads the tags on your shopping and finds out that, for example, the wine you bought is a 75-centilitre bottle of Chardonnay. It also knows when and where it was bottled, its best-before date, information on the wine region, what temperature to serve it at, perhaps even which foods in your fridge would go well with it.
With tag readers installed in everything from washing machines to refrigerators and cookers, clothes will be able to give their washing instructions, pre-packaged meals set their cooking times, and so on. They will tell you that the sour smell in your fridge is coming from the milk that went out of date last Tuesday. A portable interrogator in your mobile phone could call up product information on anything you scan. And tags in your clothes might solve the conundrum of where that missing sock is. The tags may even simplify recycling by making it easier to sort materials. The final cry from the tag on your empty wine bottle at the refuse site could be, “Hey, over here! I’m a glass bottle. Recycle me!”
Testing, testing
Numerous field trials are already under way to make this vision a reality. In September 2001, the Auto-ID Center remotely monitored the movements of pallets of paper towels in Missouri. Earlier this year the test progressed to tracking individual cases of items from distribution centres across the US to stores in eight states. The final phase is planned for the end of this year when low-cost tags from Alien will come together with a network of readers to track individual items such as razors.
But not everyone is pleased to see RFID becoming a reality. For one thing it will take the place of hundreds of jobs. What’s more, many people are also concerned about the privacy issues it raises. “There is a social change that happens when everything is given a unique serial number,” says Simson Garfinkel, author of Database Nation, a book that addresses privacy in the electronic age. “It creates a culture of control.” His view is echoed by Mihir Kshirsagar of the Electronic Privacy Information Centre in Washington DC. “RFID is passive,” he explains. “You can be interrogated without knowing about it.”
This gives it real potential for use in surveillance. If an insurance company wanted to collect information about a customer, for example, it could keep track of their movements via the tags in their clothes and possessions. “When you start identifying and linking the product to the person you are amassing all kinds of information,” Kshirsagar argues. “The question is how that information is treated and whether you have the option to remain anonymous. Maybe your refrigerator is wired so that it tells you when something has expired, but what if it’s also providing information about your habits to an unknown data agent?”
Sarma argues that this isn’t realistic, however. “Physics is a friend to the privacy of the individual. You cannot read tags through walls. At certain frequencies you cannot even read them through cardboard,” he explains. “Range is very limited. In one of our [frequency] bands I will be leaping for joy if we get a metre in air.” Even so, the Auto-ID Center is forming a policy council whose members, including Garfinkel, will be responsible for tackling these issues and recommending legislation or technical solutions. One drastic measure could be to “kill” the tags on purchase.
For now the Auto-ID team are concentrating on getting the basics right. “I sometimes joke that this is what the Internet was invented for,” says executive director Kevin Ashton. Maybe he is right. On the other hand, maybe it’s only a matter of time before people hack the network and take control of your kitchen. Burnt lasagne and warm Chardonnay, anyone?