JUST WHEN BLUETOOTH looked like the ticket
to a wireless lifestyle, the power of magnets
could make it a thing of the past.
Electrical engineers at UC San Diego recently
demonstrated a technique that sends low-power magnetic fields through the human body,
proving a concept that could one day enable
better communication between wearable gadgets,
such as a smart watch or fitness wristband.
The technology came from the lab of Professor
Patrick Mercier, co-director of the Center for
Wearable Sensors and affiliate of the Center for
Wireless Communications. Mercier says the method
could yield a lower power and more secure alternative to current Bluetooth wireless technology.
Most mobile and wearable devices transmit
information wirelessly using Bluetooth radios,
which work well when communicating over short
distances—until a body stands in the way. Since
Bluetooth radio signals don’t travel easily through
biological tissues, they require a battery-draining
power boost to overcome the obstruction. On the
other hand, magnetic fields travel freely through
biological tissues, allowing signals to be communicated with little interference.
To demonstrate magnetic field human body
communication, Mercier and his team wrapped
insulated coils of copper wire around the head,
arms and legs of one of their lab members. They then
ran an electric current through the coils to produce
magnetic fields and measured how well magnetic
signals transmitted from one part of the body to
another: arm to arm, arm to head and arm to leg.
They found that the signal losses were as much as
10 million times lower than those using Bluetooth.
“This technique will allow us to build much lower
power wearable devices,” says Mercier, who also
believes that magnetic communication through the
body could provide more security than Bluetooth
networks, which are vulnerable to hacking because
they transmit data over the air.
For those worried about potential health risks
associated with passing magnetic signals through
their bodies, Mercier also points out that the
technique transmits signals much weaker than
those produced by the Earth’s natural magnetic field.
The work is still a proof-of-concept demonstration,
yet researchers envision developing the technology
for applications such as wireless sensor networks that
could one day allow for full-body health monitoring.
Signals sent through the body
could be the future of wireless.
BY LIEZEL LABIOS, M.S. ’ 10, PH.D. ’12
co-director of the
Center for Wearable
Sensors and affiliate of
the Center for Wireless
Signal losses were
as much as 10 million
times lower than