University of Washington engineers have created a new wireless communication system that allows devices to interact with each other without relying on batteries or wires for power.
The new communication technique, which the researchers call “ambient backscatter,” takes advantage of the TV and cellular transmissions that already surround us. Two devices communicate with each other by reflecting the existing signals to exchange information.
The researchers built small, battery-free devices with antennas that can detect, harness and reflect a TV signal, which then is picked up by other similar devices. The technology could enable a network of devices and sensors to communicate with no power source or human attention needed.
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Transcript
00:00:01
>>In this project we introduce a new wireless primitive called
Ambient Backscatter that enables interactive devices that compute
and communicate without any batteries.
>>To create a visual sense of what we have set out to do,
we created devices that have no batteries and yet can
interact with users and communicate with other devices.
>>Here the user initiates communications by swiping the
touch sensor on the left device. The right device blinks an
LED to confirm reception.
>>The cool thing here is that neither of these devices
have any batteries.
>>Ambient Backscatter enables wireless communication by
leveraging the signals all around us, instead of generating our own.
>>Say two devices, Alice and Bob, need to communicate.
Alice can send a message to Bob by either absorbing
or reflecting signals from a nearby TV tower.
>>So for example, Alice sends a 0 bit by absorbing all
the incident TV signals and a 1 bit by reflecting these TV signals.
>>Alice and Bob do not generate their own RF signals,
and they use no batteries. Thus Ambient Backscatter enables
wireless communication out of thin air.
>>Here we demonstrate an offline payment application.
Each card has some onboard value.
>>This battery-powered payment terminal reads and displays
the initial value in card 100. Its initial balance is 110.
00:01:27
>>Then with no terminal present, touching a button on card
#209 transfers funds directly to card 100; the entire transaction
is powered by ambient RF.
>>Now we use the payment terminal to check the new balance on
card 100. It has increased to 130.
>>This is just one example of what we can enable by using
existing wireless signals as both a source of power
and a communication medium.
>>Now imagine a world where everyday objects such as
keys, wallets, and sunglasses are enabled with
Ambient Backscatter tags.
>>These tiny battery-free devices can leverage ambient
WIFI, TV, or cellular signals to communicate with each
other and localize themselves.
>>For example, if a person loses his keys
the couch can use Ambient Backscatter to communicate
with the lost keys and alert the user.
>>This technology will enable smart homes, smart cities
and an internet of things.
>>Tiny Ambient Backscatter devices can also be embedded deeply
into inaccessible sites such as concrete walls, floors, or roofs.
>>Since the embedded devices have no battery, they last forever and
require zero maintenance.
>>Such tags can leverage ambient signals for sensing and
communication, and enable long-term home monitoring and
industrial applications.
00:02:47
>>Beyond these example applications, what we are doing
is transforming existing ambient RF signals into a source
of power and a communication medium.
>>This new functionality can create opportunities
in multiple application domains.
