Build a network with your body; Through-body communication

promises to turn us all into Vulcans. But can ever it

escape the lab?

David McNeill, Miguel A. Quintana.

IT WAS a Michael Jackson video moment. We had come to see Nippon Telegraph and 
Telephone's new killer technology at the Japanese telecom giant's Smart Devices 
Lab in central Tokyo. Our guide was the quietly spoken lead researcher, Mitsuru 
Shinagawa, accompanied by his equally intense colleagues - a group of men so 
cerebral we were all but physically warmed by their collective brainpower. So 
it was disconcerting that when the demonstration started what leaped into my 
mind was a dumb pop-culture reference.

Shinagawa and his team had rigged up a scene that came straight from Jacko's 
video for the 1983 hit Billie Jean . A securely locked safe was placed next to 
a perspex panel in the floor. As Shinagawa stepped onto the panel, it lit up. 
Then he reached out and tugged at the safe door - and it opened. He didn't 
moonwalk or spin on his heels, but the demonstration was impressive 
nevertheless. The safe had picked up a signal sent from a smart card hanging 
round Shinagawa's neck but, rather than relying on wires or radio waves, the 
signal travelled to the safe through his body. The lock recognised him merely 
by his touch.

In Star Trek , Mr Spock was famously able to use the "Vulcan mind meld" to 
download information just by putting his hands on people's skulls. Now 
Shinagawa wants us all to be able to transfer information this way. The idea 
first became practical in the 1990s, but early attempts to make use of the 
body's natural electrical conductivity proved disappointing. Our skin is not a 
very good conductor so transfer was sluggish, and having clothes covering most 
of our bodies only made matters worse.

Shinagawa and his group believe they have now solved the key problems. Their 
system, called RedTacton, borrows an important component of laser printers to 
turn the body into a resilient, high-speed data pipe with a capacity equal to 
that of a fast broadband connection. With a RedTacton card in your PDA or 
cellphone and your skin acting as a data cable, you can exchange business cards 
or documents with whatever or whoever you touch. It means a complete career 
resume can now be transferred in a quick handshake.

This is only the start. How about cars, photocopiers and cellphones that change 
their settings to your personal preferences the moment you lay hands on them. 
Or vaults and desk cabinets that open only when authorised people reach for the 
lock, drug bottles that sound an alarm if an ageing grandparent tries to take 
the wrong pill, advertising panels that explain themselves to punters who tap 
them, or vending machines that respond to soft skin rather than hard cash. We 
could swap reams of documents, photo albums or even home movies simply by 
pressing palms. So how close are we to this digital nirvana?

Since the 1990s, what techies call near-field intra-body communication has been 
one of industry's hot topics. The Massachusetts Institute of Technology's Media 
Lab investigated using the body to connect wearable computers and other 
gadgets, and even produced a prototype. IBM, Tokyo University and the Korea 
Institute of Science and Technology followed suit.

In 2004, Microsoft patented a system designed to transform a host of small, 
wearable sensors into a personal area network. The company suggested it would 
allow you to link things like blood pressure meters inside earrings, say, with 
a PDA so you could monitor your health in real time. (The patent suggests the 
technology could be used on animals too, though why Lassie might need a 
digitally enabled diamante clip-on isn't clear.) In future, it seemed, 
networking would be as simple as holding hands. That was the idea, but 
protracted problems got in the way.

The body is a poor conductor, so it is hard to make anything but small currents 
flow through it. Transferring these weak signals is made still more difficult 
by the fact that current will only flow through a complete circuit; if current 
is to flow down your arm to a door lock, it must also be able to flow from the 
door via the floor, say, back to your body. Also, unlike the components in a 
conventional electrical circuit, each of the elements in this circuit - things 
like your body, clothes, shoes and the floor you're standing on - have 
different electrical properties. Sudden changes in resistance caused by moving 
your feet, or simply sweating, can break the circuit. And electrical "noise" 
from nearby equipment can easily swamp the weak signal. Attempts to address the 
problems led to prototypes that consumed excessive amounts of power. They were 
also unreliable and worked little faster than an old-style telephone 
modem.Unleash the flood

Now NTT claims to have a better solution. Shinagawa and his team have boosted 
transfer speeds from a trickling 50,000 bits per second to a flood of 10 
million bits per second. They have also miniaturised the transceiver at the 
heart of RedTacton that transmits and receives these signals. The team is now 
working to shrink the device further still, to the size of a flash memory card 
- small enough to slot into a phone or other portable electronic device.

RedTacton's transmitter encodes a message such as an email into a high-speed 
stream of electrical pulses which it then sends to an electrode. This acts like 
a short-range radio antenna, and induces a matching pulsed electric field in 
your skin . When you touch someone else, the field in your skin induces an 
identical field in theirs, and the signal is picked up by the antenna of their 
RedTacton. Shinagawa says that neither the transmitter nor the receiver need to 
be in direct contact with the skin. They can operate at up to 10 centimetres 
away. This means the system will work if your RedTacton-enabled PDA is in your 
jacket pocket or shoulder bag.

RedTacton differs in that it doesn't rely exclusively on conventional 
electronics to detect and amplify the weak, high-frequency signals. Instead it 
uses an electro-optical crystal similar to those used in laser printers, which 
responds to an electric field by changing the polarisation of a beam of light 
passing through it. By using the data signal to provide the electric field, 
Shinagawa can encode the data in the polarisation of a beam of laser light. A 
light sensor detects these polarisation changes, and feeds this information to 
signal-processing circuits, which reconstruct the original data.

This might seem unnecessarily complex, but the design offers a number of 
advantages over conventional electronics. First, by converting the electrical 
signal into light, the electro-optical crystal provides complete electrical 
isolation between the user's body and the circuits that process the signal. 
This helps to stop electrical noise passing through the receiver. Also, the 
crystal can be designed to amplify signals at some frequencies more than 
others, which helps it to filter out noise.

With more signal and less noise getting through, Shinagawa's design works up to 
200 times faster than earlier through-body systems, and about three times 
faster than other short-range wireless systems such as Bluetooth. And as the 
demonstration showed, two-way communication works through thick clothing, shoes 
and even high heels. It can also pass through wood and metal surfaces, though 
it struggles with plastic.Watching you

So far so good, but the big-brother implications are obvious. Imagine 
productivity-obsessed bosses installing RedTacton sensors in walls and chairs, 
allowing them to monitor every move an employee makes, down to each opening and 
closing of a filing cabinet, door or safe. At the end of the day, a printout 
might reveal that you entered the building at 9.37 am, spent exactly 5 hours 
and 26 minutes sitting at your desk and 38 minutes in the toilet. Of course, 
conventional smart cards will already provide some of that information (though 
few employers have installed card readers in the restrooms), but unlike smart 
cards, RedTacton receivers can exchange information with other devices without 
a user's knowledge.

There was another sign of potential difficulty when we visited the lab. The 
demonstration looked foolproof, until we grabbed a startled Shinagawa by the 
arm, rerouting the current from him to us and opened the safe door ourselves. 
That could be less secure than old-fashioned smart cards.

Besides, surely wireless networks such as Bluetooth make this sort of approach 
redundant? Not so, says Shinagawa. "Wireless transmission can be intercepted by 
anyone within range. RedTacton only allows transfer with people in your 
immediate vicinity."

Yet technology that allows the transfer of information by touch is also 
uniquely vulnerable. Is that guy who bumped into you on the train just clumsy 
or is he rifling around in your personal files? Or uploading a virus into your 
system? Shinagawa says that while RedTacton will never be entirely secure, it 
offers unrivalled convenience, particularly in an environment where smart cards 
and keys are constantly used to get in and out of rooms or files. "It's 
primarily meant for tasks that are repeated several times a day," he says. "We 
know that people have concerns, but if the benefits outweigh those concerns we 
are confident they will use RedTacton."

If the technology is that promising, where are the other players? Sony 
experimented with a similar device before abandoning it a couple of years ago. 
In 2004, Matsushita Electric Works, a division of Sony's arch-rival, claimed to 
have developed the world's first practical application of what it called "human 
body communication". Its engineers produced a matchbox-sized device that was 
worn on the wrist. It could transfer data at 3700 bits per second when the 
wearer touched a "targeted communication terminal".

Matsushita announced an initial application that might one day replace the 
supermarket barcode scanner: a sales clerk wearing the device would merely 
touch a product to register it on a till. A barcode system would have done the 
job just as well and at lower cost, but Matsushita claimed its system was 
better because it was "sanitary and speedy". That sounds a weak hook for a 
product, so it is perhaps not surprising that the system was hardly used and 
Matsushita is not pursuing it. According to a spokesman, the company "feels a 
bit uncomfortable" about using the human body as a conduit for a data network. 
"There needs to be a lot more testing before the company is convinced that this 
technology is safe," he says, referring to the potential dangers of 
electromagnetic signals from mobile phones on the body.

NTT, meanwhile, insists RedTacton raises no such concerns. It claims the system 
produces a signal 1 million times lower than the safe exposure level, and does 
not interfere with pacemakers. "There is no question of safety issues," a 
spokesman says.

So NTT is ploughing on, and with its huge resources and world-class engineers 
few would bet against it succeeding. The rest of the pack appears to have taken 
a wait-and-see approach. "The benefits of touch communication without having to 
reach for smart cards are obvious," says Matsushita's new-business manager, 
Kenji Doi. "But for now we cannot find a commercial application." And until a 
killer product emerges, RedTacton will remain an entertaining but expensive 
toy. Shinagawa says NTT is "in discussion" with several firms - one a "major 
construction company" - and is edging towards commercialisation.

He and his colleagues have already demonstrated how RedTacton might be used. In 
2005 they constructed CarpetLAN, a floor made up of 22 carpet tiles, each with 
a built-in RedTacton transceiver. People or objects such as computers or home 
appliances standing on the floor become linked in a high-speed network. 
Shinagawa says that normal gestures such as touching objects or walking over 
the floor could trigger pre-configured processes such as opening a door or 
downloading new email messages. And in a paper on CarpetLAN presented at the 
2005 Ubiquitous Computing conference in Tokyo, Shinagawa stated his eventual 
aim: to embed transceivers in Japanese tatami - straw mats - and to connect all 
the floors of the world into a network.

Yet while we wait for our carpets to talk to us, we might begin to use our 
bodies to control our cars - at least if engineers at Ident Technology in 
Munich, Germany, have their way. Their system, called Skinplex, uses 
transceivers integrated into car seats to send signals through the bodies of 
car occupants. It can be used, Ident suggests, to stop passengers catching 
their fingers in electric windows and to automatically adjust seats or air 
conditioning to suit the car's occupants.

And how about using this technology as a way of paying for goods and services? 
In Japan, cellphones are already used as a virtual wallet to pay for drinks, 
train tickets, restaurant meals and a lot more. Thousands of retail outlets 
accept payment by customers who swipe their phones over a store sensor. Now 
imagine if you could embed a RedTacton device in those phones, turning your 
entire body into a communication device that glides through ticket barriers and 
turnstiles without you ever having to reach for a smart card or cellphone. "The 
mobile phone could become a Trojan horse for RedTacton," says NTT product 
manager Toshiaki Asahi. "Because so many people carry them we see it as the 
best way to get this technology out there." NTT already has a finger in this 
pie, thanks to its involvement in the Edy service, a virtual cash network for 
cellphones users in Japan.

A RedTacton device in every cellphone may still be a distant dream, but it's 
fun to speculate on what could happen if this technology ever leaves 
Shinagawa's laboratory. The NTT marketers may already be working on their sales 
pitch. Here we go, they could say, the world is about to become a lot more 
touchy-feely.

David McNeill is a freelance writer. Miguel A. Quintana is a researcher and 
translator. They are both based in Tokyo
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