Our Bodies, Our Wires

In his gadget-filled office at Tokyo Medical and Dental University, Prof. Kohji Mitsubayashi tells a visitor to touch a transmitter with one hand and a receiver with another. Voila! A jaunty TV jingle blares from attached speakers. The visitor releases her grip, and the music stops. Becoming a human circuit--with electrical signals coursing from fingertip to fingertip--is so fascinating that visitors usually repeat the act. "Fun, isn't it?" says Mitsubayashi.

Japan is abuzz over such body-based technology as the ultimate wireless tool. Some Japanese companies are experimenting with systems that exploit the weak currents that pass through the skin itself, while others, including telecom giant NTT, use electrical fields on the surface of the body. Sending signals this way is more secure than with existing wireless systems like Wi-Fi, because the signals can be intercepted only through touch. Products are on the way. In 2004, Matsushita Electric Works released an electrical food scale, the first appliance based on so-called touch technology. Food trays were embedded with chips that transmitted the price per gram through a clerk's fingers to a device that looks like a watch, which flashed the price of the order.

Further possible applications abound. Some companies are working on a device that could open doors automatically by transmitting an ID code through the skin to a receiver embedded in the doorknob. The real killer app for such technologies may be in the medical industry, says Mitsubayashi. A patient who needs constant monitoring could wear a finger sensor to collect data (body temperature, heart rate, etc.) without all the wires. NTT has a prototype medicine bottle that prompts a personal digital assistant in your purse to beep a warning about possible side effects. "This can liberate people with health problems," says Mitsubayashi, who's working with interested companies in the field. "In an aging society, it's very important." Not to mention very cool.