The Skin Effect

A not-so-new technology has seen a resurgence in viability according to developments announced recently by Nippon Telegraph and Telephone (NTT). The technology is based on using the surface of your skin as a transmission medium. Your body would provide the communications path from a PDA in one hand to, say, a cell phone in the other. No, this is technically not wireless communications but a technology that depends on a weak electric field on your skin to send data from a transmitter to a receiver.

The technology has been plagued for years by the inability to transmit data more than a few centimeters at a very limited bandwidth of only tens of kilobits per second. Now, new developments enable data transmission from anywhere on the body at a maximum rate of 10 Mb/s.

RedTacton from NTT is a new human area networking technology that uses a super-sensitive photonic electric field sensor to achieve duplex communications over a body. As stated on the RedTacton website, the sensor enables weak electric fields to be measured by detecting changes in the optical properties of an electro-optic crystal with a laser beam.

In operation, a RedTacton transmitter and receiver must be in contact with your body (they even work through clothes and shoes). The transmitter induces a minute electric field modulated with data which is sensed by the receiver. The principle here is that the optical properties of the electro-optic crystal vary according to changes in the electric field. The laser beam in the receiver detects the optical changes in the crystal which are converted to an electrical signal corresponding to the transmitted data. One benefit of the technology is minimal or no interference from wireless devices in congested areas because the skin is the transmission medium, not air. Other than skin, various conductors and dielectrics also can be used as transmission media.

Applications of the technology are numerous since communications can be initiated by touching, sitting, standing, walking, or jumping, among others. A shared cell phone can be personalized to an authorized user just by picking it up. Persons with access rights can unlock doors just by touching the handle. Walking over a mat with an embedded RedTacton will let an authorized person enter a secure building. Checking out at your local grocery store merely requires touching a special plate, and your checking account is debited the amount of the transaction.

This all sounds really neat until you think about some of the possible consequences of using this technology in your daily life. What happens when some unscrupulous person gets hold of my RedTacton device? What happens if I lose or misplace the device and someone uses it to gain access to my personal and financial data? What happens if by just brushing against someone as I walk down the street my identification is stolen? It would seem relatively easy for anyone to extract this kind of data, especially in light of recent news reports where hackers accessed more than 40 million credit card accounts from one clearinghouse.

I m sure suitable safeguards will be implemented over time to minimize these kinds of attacks, but, by the same token, hackers are becoming quite sophisticated in finding ways to gain access to more and more so-called secure information. Not being an early adopter, I ll still use my trusty key to unlock the door on my car.

Paul Milo
Editorial Director
[email protected]

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