Articles
A wireless communication technique that works by sending magnetic signals through the human body has been demonstrated by engineers at the University of California in San Diego. The technology could present a more secure way to communicate information between wearable electronic devices through the body, providing an improved alternative to existing wireless communication systems.
The researchers built a prototype to demonstrate the magnetic field human body communication technique – using the body as a vehicle to deliver magnetic energy between electronic devices. The prototype consists of copper wires insulated with PVC tubes. On one end, the copper wires are hooked up to an external analyser. At the other end, the wires are wrapped in coils around three areas of the body: the head, arms and legs.
The coils serve as sources for magnetic fields and are able to send magnetic signals from one part of the body to another using the body as a guide. An advantage of this system according to the engineers is that magnetic fields are able to pass freely through biological tissues, so signals are communicated with much lower path losses and potentially, much lower power consumption.
The researchers believe the prototype can be developed into an ultra low power wireless system able to transmit information around the human body, suitable for use in applications such as full-body health monitoring.
According to the researchers, the technique overcomes several barriers to the wider adoption of wireless communications systems. For example, Bluetooth technology uses electromagnetic radiation to transmit data. However these radio signals do not easily pass through the human body and therefore require a power boost to help overcome this signal obstruction.
The signal obstruction associated with magnetic field human body communication is upwards of 10 million times lower than those associated with Bluetooth radios.
Patrick Mercier, professor in the Department of Electrical and Computer Engineering at the University at the University of Californica, said: “In the future, people are going to be wearing more electronics, such as smart watches, fitness trackers and health monitors. All of these devices will need to communicate information with each other. Currently, these devices transmit information using Bluetooth radios, which use a lot of power to communicate. We're trying to find new ways to communicate information around the human body that use much less power.”
Despite its abilities, a limitation of the technique used by the prototype is that magnetic fields require circular geometries in order to propagate through the human body. Devices such as a small patch, which may be stuck on the chest and used to measure heart rate, would not work because the wearable application needs to wrap around a part of the body.
The findings were presented at the 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society in Milan, Italy.