Ambient Backscatter

In an effort to bring you the most obscure technology news with some potential future military application I have stumbled across communications using ambient backscatter.

No, I don’t understand it either but watch the video

So, some clever chaps have from the University of Washington have discovered a way for electronic devices to communicate with each other without using batteries or other on board power source, instead, they use the power of other electronic emitters, TV transmitters for example.

Low bandwidth devices can be used for all manner of applications, position information, remote movement sensors, smart power grids or even simple text messaging.

Read more at Gizmag


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Rocket Banana
August 17, 2013 4:51 pm

Great title.

At a lesser level people’s Oyster cards (and my dog) have been doing this for a decade.

Just goes to show how little power is needed to power a chip nowadays.

August 17, 2013 5:52 pm

If I’m understanding this correctly they are using the ambient signals as a communication medium, which is… astonishing. Way beyond standard RFID / NFC comms (such as the Oyster card), or even low power devices using ambient RF as a parasitic power source.

August 17, 2013 8:48 pm

Supposedly the first ARM prototype booted off inductive current before they even attached the power rail :-)

John Hartley
John Hartley
August 18, 2013 9:50 am

A decade ago, I was briefly scared silly, when home alone, ghostly voices reverberated around my lounge. Turns out some boy racer with an illegal CB/mega stereo in the pub car park next door, was radiating to such an extent that it was picked up by the speakers in my (off) home CD.

Red Trousers
Red Trousers
August 18, 2013 10:51 am

I have a tenuous level of understanding of this sort of thing, but I think the scientific principle is reasonably established, it is the engineering of it into reliably working product that will probably prove difficult.

Rocket Banana
August 18, 2013 11:58 am

John Hartley,

I remember one of the cooking pans we had in student accommodation talking to us once. I kid you not. God knows what power the cabbie’s transmitter was who was admittedly parked just outside (20m or so from the pan).

Brian Black
Brian Black
August 19, 2013 6:01 am

” I remember one of the cooking pans we had in student accommodation talking to us once.”

Did you use a lot of drugs as a student, Simon?

August 20, 2013 3:25 pm

I don’t think what they are talking about here is really about either induction transmission or inductive powering I.e. your talking pots oyster card.

they are talking about transmission information via the relative absorption of an ambient signal ????
see 30 seconds ish to 1:10 ish

I think this related to a new anti-stealth radar system based on ambient signals
And relies on the HOLE in EM signals where the plane is, and where “static should be”
a silhouette if you will of an F22

now apparently this works,

but the above concept take this one step further is what i think we are saying ?!?!

Rocket Banana
August 20, 2013 5:56 pm


I got the impression that the device was powered by ambient RF otherwise it would need batteries. After that, yes, I agree they’re either talking about the “holes” in the RF or re-transmitting a 180 degree out-of-phase signal to give the effect of an absorbed signal (superposition).

I suppose it’s a bit different to RFID but not by much, besides I can’t quite see how a relatively insignificant absorption can affect the local RF field enough to detect, unless the detector is highly directional which goes against much of what they were saying when they come to “find their keys”.

August 21, 2013 8:02 am

Hi Simon,

Agreed it has to get its power from somewhere. Its never going to be able to extract more energy than the incomming wave at the very best though ?

Out-of-phase will work at short distance, or in line with the transmitter, but if reciever “B” is at 90 degrees geographically the waveforms wont add up correctly.
Like you said a very directional solution. like your thinking tho.

Im quite facinated by this. Im wondering if its using something like passive sonar, Statistical analysis of background em radiation over time to find significant frequencies. i think i might have to go a hunting for more info.