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Ambient backscatter tech allows devices to communicate, sans batteries


August 14, 2013

Two ambient backscatter test devices are able to communicate, despite having no batteries ...

Two ambient backscatter test devices are able to communicate, despite having no batteries or power cords

In order for the Internet of Things to become a reality, devices will need to be able to communicate with the internet and with one another. If they have to be powered up in order to so, however, a lot of electricity is going to be wasted. That’s where a new technology known as “ambient backscatter” comes into the picture. Developed by engineers at the University of Washington, it uses ever-present existing TV and cellular signals to provide the power and medium for battery-less communications.

Each device utilizing the ambient backscatter system is equipped with an antenna that picks up TV or cellular signals and converts them into electricity, which it then uses to reflect a Morse code-like version of that signal. Similar antennas on other devices in turn detect that coded, reflected signal, and can respond accordingly. No human intervention is required.

Not only would the technology let devices communicate without being turned on, but it would also allow for things such as structural sensors to be embedded in concrete or other materials, where they would be impossible to access for battery-changes – as long as the signals could reach through the material to their antennas, they could communicate.

Led by Prof. Shyam Gollakota, U Washington researchers added the antennas to credit card-sized circuit boards. Each device had an integrated LED that illuminated when it received a signal, but no battery. It was found that pairs of the cards placed several feet apart could communicate with one another, even when up to 6.5 miles (10.5 km) away from the nearest TV transmission tower. The rate at which they could exchange information was reportedly sufficient to relay data such as sensor readings or text messages.

This, in turn, leads to another possible use for the technology. In the future, smartphones might be able to use ambient TV and cellular signals to transmit text messages, even once their battery has died. Additionally, ambient backscatter tags on those phones (or on anything else) could be used to transmit their location if they were misplaced.

More information is available in the video below.

Source: University of Washington

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth

I remember in the early 1950's a theme and variation of this device was available in kit form for a battery free radio albeit a crystal set with a set of horrible "brown's headphones. Sold by Levinsons a hobby store in Sydney, Australia.

It consisted of 2 tuned circuits, one set to the strongest RF field from an AM radio station. The output was rectified through a bridge rectifier to provide DC to amplify the second variable tuner output to a set of phones. One of the earliest transistors was used as the amp. Not quite the same but a variation on the "free power" concept. Another variation available was a low powered transmitter for morse code - had a range of about 3 metres, not very useful when you could yell across the room...!!!

14th August, 2013 @ 06:40 pm PDT

Nifty. I have seen one-way communication without power, such as a crystal radio, but never two-way communication without power before.

14th August, 2013 @ 07:10 pm PDT

Transmit texts? Improbable. User input is impossible once the device is powered down, which defeats the entire purpose, though the location tagging might be useful.

Except that the range is only several feet.

I think the uses would most likely lend themselves to areas like non-smart item retrieval, google-glass style VR, sensors, and credit cards.

Racqia Dvorak
14th August, 2013 @ 07:26 pm PDT

Hope that this doesn't create interference or noise in TV or Cellular signals. Great idea otherwise, would love to see this used for vehicles and license plate tags.

Facebook User
14th August, 2013 @ 10:43 pm PDT

a long time ago, people lit up their garden lights from high powered AM transmitters in Germany

- which was illegal there and then!

nothing new under the sun (moon)

Hans Schaefer
14th August, 2013 @ 10:44 pm PDT

and we wonder why the insects and bee's are dying

science ninja
15th August, 2013 @ 09:42 am PDT

As none of us live in deep caves completely devoid of light, whats wrong with a button sized solar panel on the device that can gather extra power from the ambient light in a living room.

It would certainly provide more power then this.

15th August, 2013 @ 03:17 pm PDT

science ninja: I don't wonder. It's Monsanto's chemicals.

Don Duncan
15th August, 2013 @ 05:59 pm PDT

Wow! This is very interesting! I wonder how much this cost. I see this as a very important tool most specially if there are emergency cases where our cell phone batteries are dead.

Rita Adams
15th August, 2013 @ 07:40 pm PDT

in the late 50's my brother had a aprox 3" red missile shaped radio the silver top was a antenna you pulled up to tune in the stations am i think, used ear buds, no volume control but loud enough and no batteries used in it at all ! it sure would be nice if that company was still around making that product with both am/fm. would be great for power outages storms and free energy radio !!!!!!!!!

16th August, 2013 @ 11:04 am PDT


Was it this?


19th August, 2013 @ 06:41 am PDT
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