Microsoft Obtains Patent for Use of Human Body as Power And Data Transmitting Medium

On June 22, 2004, the US Patent Office issued a patent (serial no. 6,754,472) to Microsoft Corp for a method for networking devices coupled to a human body by using the body as both a power conduit (providing power to the devices) and a data bus (for data exchange to and between the devices).Microsoft Obtains PatentThe patent document refers to numerous devices now worn by people, such as wristwatches, pagers, PDAs and even small displays mounted on headgear. The goal is to reduce the multiplicity of input/output devices and power sources. The basic idea is to transmit one or more power signals (of differing frequencies) over the body. Each device is configured to reject all power signals except the signal at its selected frequency. In this way, a number of devices can simultaneously be serviced by a combination signal of different frequencies transmitted over the body. Digital data and other information signals, such as audio signals, can be modulated on the power signal using frequency and/or amplitude modulation techniques. Electrical power may be generated for the entire network by a device for converting kinetic to electrical energy, such as a shoe-borne device. Human data input can then occur via a number of means, including a keyboard defined on a region of skin making use the electrical resistance of the body. Larger networks may be constructed by two or more persons physically touching each other. Microsoft's patent document concedes that its approach is but one attempt at implementing a personal network, known in the industry more generally as a personal area network (PAN). Others have implemented systems making use of radio signals, infrared communications signals, and near-field, intrabody communication signals. In order to minimize the physical sensation resulting from the transmission of signals, the patent document asserts that the signals may be limited to less than 100 volts. Given the continuing controversy over mobile phone radiation, even at such low voltage, the health effects of prolonged exposure to electromagnetic fields may be the subject of future concern. For another report on this subject, see: http://makeashorterlink.com/?W23E42BB8. Summary by: Peter K. Wang