The NTT, the Japanese communications company, has developed a technology called RedTacton, which can send data over the surface of the skin at speeds of up to 2Mbps — equivalent to a fast broadband data connection. Using RedTacton-enabled devices, music from an MP3 player in your pocket would pass through your clothing and shoot over your body to headphones in your ears. Instead of fiddling around with a cable to connect your digital camera to your computer, you could transfer pictures just by touching the PC while the camera is around your neck. And since data can pass from one body to another, you could also exchange electronic business cards by shaking hands, trade music files by dancing cheek to cheek, or swap phone numbers just by kissing.

RedTacton uses the minute electric field emitted on the surface of the human body. Technically, it is completely distinct from wireless and infrared. A transmission path is formed at the moment a part of the human body comes in contact with a RedTacton transceiver. Physically separating ends the contact and thus ends communication. Communication is possible using any body surfaces, such as the hands, fingers, arms, feet, face, legs or torso. RedTacton works through shoes and clothing as well.

How it works

The NTT is not the first company to use the human body as a conduit for data: IBM pioneered the field in 1996 with a system that could transfer small amounts of data at very low speeds, and recently Microsoft was granted a patent for “a method and apparatus for transmitting power and data using the human body.”

But RedTacton is arguably the first practical system because, unlike IBM’s or Microsoft’s, it doesn’t need transmitters to be in direct contact with the skin — they can be built into gadgets, carried in pockets or bags, and will work within about 20cm of your body.

RedTacton doesn’t introduce an electric current into the body — instead, it makes use of the minute electric field that occurs naturally on the surface of every human body. A transmitter attached to a device, such as an MP3 player, uses this field to send data by modulating the field minutely in the same way that a radio carrier wave is modulated to carry information.

Receiving data is more complicated because the strength of the electric field involved is so low. RedTacton gets around this using a technique called electric field photonics: A laser is passed though an electro-optic crystal, which deflects light differently according to the strength of the field across it. These deflections are measured and converted back into electrical signals to retrieve the transmitted data.

Using a new super-sensitive photonic electric field sensor, RedTacton can achieve duplex communication over the human body at a maximum speed of 10 Mbps.

1. The RedTacton transmitter induces a weak electric field on the surface of the body.

2. The RedTacton receiver senses changes in the weak electric field on the surface of the body caused by the transmitter.

3. RedTacton relies upon the principle that the optical properties of an electro-optic crystal can vary according to the changes of a weak electric field.

4. RedTacton detects changes in the optical properties of an electro-optic crystal using a laser and converts the result to an electrical signal in a optical receiver circuit.

The transmitter sends data by inducing fluctuations in the minute electric field on the surface of the human body. Data is received using a photonic electric field sensor that combines an electro-optic crystal and a laser light to detect fluctuations in the minute electric field.

The naturally occurring electric field induced on the surface of the human body dissipates into the earth. Therefore, this electric field is exceptionally faint and unstable. The photonic electric field sensor developed by NTT enables weak electric fields to be measured by detecting changes in the optical properties of an electro-optic crystal with a laser beam.

RedTacton has three main functional features

Touch

Touching, gripping, sitting, walking, stepping and other human movements can be the triggers for unlocking or locking, starting or stopping equipment, or obtaining data.

Duplex, interactive communication is possible at a maximum speed of 10Mbps. Because the transmission path is on the surface of the body, transmission speed does not deteriorate in congested areas where many people are communicating at the same time.

Taking advantage of this speed, device drivers can be downloaded instantly and execute programmes can be sent.

Any media

In addition to the human body, various conductors and dielectrics can be used as transmission media. Conductors and dielectrics may also be used in combination. A communication environment can be created easily and at low-cost by using items close at hand, such as desks, walls, and metal objects.

Some futuristic applications of human networking are:

(e) Connect to N/W just by putting laptop on table: An electrically conductive sheet is embedded in the table. A network connection is initiated simply by placing a laptop on the table. Using different sheet patterns enables segmentation of the table into subnets.

(f) Just touching a make it yours: Your own phone number is allocated and billing commences. Automatic importing of personal address book and call history.

(g) User Verification and unlocking with touch: Carrying RedTacton capable device in one’s pocket, ID is verified and the door unlocked when the user holds the doorknob normally.

(h) Touch a printer to print: Print out where you want just by touching the desired printer with one hand and a PC or digital camera with the other hand to make the link.

Conclusion

Human body networking is more secure than broadcast systems, such as Bluetooth, which have a range of about 10m. With Bluetooth, it is difficult to rein in the signal and restrict it to the device you are trying to connect to. You usually want to communicate with one particular thing, but in a busy place there could be hundreds of Bluetooth devices within range. As human beings are ineffective aerials, it is very hard to pick up stray electronic signals radiating from the body. This is good for security because even if you encrypt data it is still possible that it could be decoded, but if you can’t pick it up it can’t be.

In the near future, as more and more implants go into bodies, the most important application for body-based networking may well be for communications within, rather than on the surface of, or outside, the body. An intriguing possibility is that the technology will be used as a sort of secondary nervous system to link large numbers of tiny implanted components placed beneath the skin to create powerful onboard or in-body computers. So we can conclude that this technology will change the future of wireless communication.

Mr Parteek Bhatia, Faculty, Department of Computer Science & Engineering, Thapar Institute of Engineering & Technology, Patiala.

Mrs Sanmeet Bhatia is doing Masters in Enginnering at Thapar Institute.

Why Named RedTacton?

Because with this technology, communication starts by touching (Touch), leading to various actions (Act on) and the colour red to convey the meaning of warmth in communication. Combining these phrases led to the name, "RedTacton".

How does RedTacton differ from other communication systems that use the human body?

Several “human body communication” technologies using the human body as a transmission medium have been reported in the past. But RedTacton employs a proprietary electric field/photonics method which uses a sensor which measures faint electric fields by using a laser beam to detect fluctuations in the optical properties of an electro-optic crystal that are caused by peripheral electric fields.

www.tribuneindia.com/2006/20061124/science.htm#1