Most days, you have to work to find crazy-cool tech stories, but some days they seem to fall from the sky like the foodalanche in Cloudy with a Chance of Meatballs — stories like “Wireless devices that function without batteries.”
Some engineers at the University of Washington have managed to create several such devices, allowing users to interact or communicate with each other battery-free by repurposing existing radio signals.
It’s called ambient backscatter, a technique whereby a device appropriates wireless signals already bouncing around in the atmosphere and uses them both as a power source and a way to communicate with other devices. Ambient backscattering has similarities to RFID, but differs in that it doesn’t require a high-power signal source, has a relatively small footprint and can communicate device-to-device — unlike RFID, where tags have no ability to detect each others’ existence.
I’m going to borrow the example in
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