I Transceive the Body Electric
By Mark Frauenfelder, Wed Apr 06 08:15:00 GMT 2005

A new technology being developed by NTT turns people into data busses.


Costa Rica, 2012: After spending a day walking through the magnificent rainforests, you return to your hotel with a digital camera full of photographs of monkeys, army ants and exotic flowers. You walk up to a photograph printing kiosk in the lobby and place your finger on a silver-colored button. Instantly, the camera in your pocket comes to life. A special frequency modulator in the camera encodes the data in its flash memory, sending the data across the surface of your body at a rate of 10Mbps, where it jumps off your fingertip and into the transceiver circuit in the printer kiosk. Thumbnail images of your photographs appear on the screen, allowing you to pick out the ones you'd like to print or e-mail to friends. At the same time, the kiosk has queried the Web site of the camera's manufacturer, and has discovered a new software driver for you camera. After you click the "OK" button, the driver update travels from the kiosk to the camera, and is installed.

The above scenario isn't necessarily as farfetched as it sounds. If Japanese telecom giant NTT has it's way, RedTacton, a personal area networking (PAN) technology that makes use of the electrical field that naturally surrounds the human body, will be surrounded your body in a few years. NTT has already made RedTacton transceiver prototypes, and this month the company will begin loaning them to potential partners to develop devices using the technology, which work using standard TCP/IP protocols.

NTT believes there are many uses for RedTacton beyond being a replacement for certain Bluetooth or IR applications. It could for example, be used as a kind of RFID. When you touch a door handle at a secure facility, the RedTacton transceiver would look at the ID number stored in the mobile device in your pocket and decide whether or not to let you in. Or a bottle of medicine might sound an alarm if you are not the person to whom the pills have been prescribed.

NTT's RedTacton is just one of several research efforts looking at using the human body as a data transmission conduit. IBM and the Massachusetts Institute of Technology Media Lab demonstrated a skin-to-skin PAN at Comdex in 1996, in which two people exchanged business card data by shaking hands. And in 2004, Microsoft was granted a patent for a "method and apparatus for transmitting power and data using the human body".

Microsoft's patent suggests that users wear a pair of electrodes to ensure good electrical contact with a user's body, the thought of which could make some people's skin crawl, even though it is highly unlikely that you could ever feel a shock from the tiny amount of current the system would send through your body.

NTT's technology represents a major improvement over earlier "skin-to-skin" networks because it doesn't require direct contact between a device and the user's skin. It works through clothing, and from a distance of 8 inches. Instead of passing a current through your body, RedTacton modulates the existing electric field on a body's surface. The body's electric field is extremely weak and is difficult to measure directly; however RedTacton uses a component in the receiving circuit called a photonic electric field sensor, which makes it possible to sense minute changes in an electrical field by measuring the changes in the optical properties of a photosensitive crystal. RedTacton has other uses apart from human-to-human and human-to-device data transfer. Cars, furniture, water, and other surfaces could be used as transmission media as well. One possible application would allow you to place your notebook computer on a table and have it connect to a high-speed network.

The limited range the of RedTacton may actually be more desirable than Bluetooth or Wi-Fi in some cases, because it would be more difficult for someone to eavesdrop on the signal. Also, because the data is transmitted over the surface of the body, the transfer speed doesn't get bogged down in places where there's a lot of wireless congestion.

If the idea of using electricity on your body is a little shocking, remember this -- our nervous systems couldn't function without electricity.