Will Battery-Free Ambient Backscatter Power the Internet of Things?

Researchers built a device that modulates ambient TV and mobile signals to create new wireless networks.


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The internet of things refers to an increasingly connected network of everyday objects like appliances, gadgets, vehicles, storefronts, even medication. The term itself is ambiguous and outmoded—it's just the internet, only not on a computer—but the idea is real and important.

It’s perhaps not very surprising that the smart homes, grids, and offices that such technology enables require large amounts of energy, the extent of which renders many applications impractical. This has been a major hurdle for scientists and engineers alike.

But a new discovery by researchers at the University of Washington promises to recycle existing energy in an ingenious way. Scientists developed a wireless network that draws power from ambient TV and cellular transmissions, and modifies their signals with its own data. “Ambient backscatter,” as it’s called, creates a separate network that can be read by other devices.


This transponder "harvests" ambient TV signals and repurposes them to be read by a separate network.

“Our design avoids the expensive process of generating radio waves,” researchers explained in the study. “Because ambient backscatter avoids the maintenance-heavy batteries and dedicated power infrastructure of other forms of low-power communication, it enables a bevy of new applications that were previously impossible, or at least impractical.”

Ambient backscatter requires no additional power source or battery. The prototypes researchers developed are only about the size of a credit card, and while their connective capabilities are at this point somewhat limited, they are cheap and easy to build, the report claims.

Ambient backscatter requires no additional power source or battery.

Not surprisingly, researchers see this technology as a promising stepping stone toward a more efficient, sustainable “internet of things.” Just imagine: checking your smartphone to see if the oven is on, or knowing precisely when a pill has been disolved in your stomach. Such technology requires an inexpensive and energy-efficient way of broadcasting wireless signals—something traditional Wi-Fi networks mostly lack.

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So this is good news for the internet of things, even if practical applications of the technology are a ways away. In the mean time, let’s hope someone can come up with a more inspired name for the trend of broadening the internet beyond computers. And please, no more using “smart” as a prefix for every new invention. How about just “the internet?”

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