University of Washington researchers have introduced a new way of communicating that
allows devices such as brain implants, contact lenses, credit cards and smaller wearable
electronics to talk to everyday devices such as smartphones and watches.
This new “interscatter communication” works by converting Bluetooth signals into
Wi-Fi transmissions over the air.
Using only reflections, an interscatter device such as a smart contact lens converts Bluetooth
signals from a smartwatch, for example, into Wi-Fi transmissions that can be picked up
by a smartphone.
Due to their size and location within the body, the smart contact lenses are too constrained
by power demands to send data using conventional wireless transmissions.
That means they so far have not been able to send data using Wi-Fi to smartphones and
other mobile devices.
The team of UW electrical engineers and computer scientists has demonstrated for the first
time that these types of power-limited devices can “talk” to others using standard Wi-Fi
communication.
Their system requires no specialized equipment, relying solely on mobile devices commonly
found with users to generate Wi-Fi signals using 10,000 times less energy than conventional
methods.
The team’s process relies on a communication technique called backscatter, which allows
devices to exchange information simply by reflecting existing signals.
Interscatter communication uses the Bluetooth, Wi-Fi or ZigBee radios embedded in common
mobile devices like smartphones, watches, laptops, tablets and headsets, to serve as
both sources and receivers for these reflected signals.
In one example the team demonstrated, a smartwatch transmits a Bluetooth signal to a smart contact
lens outfitted with an antenna.
To create a blank slate on which new information can be written, the UW team developed an innovative
way to transform the Bluetooth transmission into a “single tone” signal that can be
further manipulated and transformed.
By backscattering that single tone signal, the contact lens can encode data — such
as health information it may be collecting — into a standard Wi-Fi packet that can
then be read by a smartphone, tablet or laptop.
Beyond implanted devices, the researchers have also shown that their technology can
apply to other applications such as smart credit cards.
The team built credit card prototypes that can communicate directly with each other by
reflecting Bluetooth signals coming from a smartphone.
This opens up possibilities for smart credit cards that can communicate directly with other
cards and enable applications where users can split the bill by just tapping their credit
cards together.