
First battery-free cellphone makes calls by harvesting ambient power - the_duke
http://www.washington.edu/news/2017/07/05/first-battery-free-cell-phone-makes-calls-by-harvesting-ambient-power/
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camtarn
Previous:
[https://news.ycombinator.com/item?id=14659236](https://news.ycombinator.com/item?id=14659236)

It's not a cellphone. It's basically an backscatter analog audio bug which
doesn't even operate on cellphone frequencies, and which has a range of only
~15 metres.

~~~
Animats
True. If they could make a Bluetooth earpiece powered this way, though, they'd
have a product.

~~~
throwanem
Would they? Those drop out often enough already, without being subject to the
vagaries of the local microwave environment in order to power themselves at
all.

Don't get me wrong - I love my Rowkin Mini, and a self-charging Bluetooth
earbud would be an awesome thing to have! I'm just not sure how realistic a
prospect that really is.

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TD-Linux
It seems that this operates on the same principle as The Thing:
[https://en.wikipedia.org/wiki/The_Thing_(listening_device)](https://en.wikipedia.org/wiki/The_Thing_\(listening_device\))

Several devices in the ANT catalog also rely on radio reflection, for example
this video transmitter:
[https://en.wikipedia.org/wiki/NSA_ANT_catalog#/media/File:NS...](https://en.wikipedia.org/wiki/NSA_ANT_catalog#/media/File:NSA_RAGEMASTER.jpg)

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pp19dd
Hmm. Think this is a far stretch from being a cellphone prototype. What I'm
seeing is a wireless microphone with a number pad prototype.

I get that the implied concept is to take power hungry components and offload
them to a nearby transmitter device, but we have that already: a wireless
phone.

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IncRnd
"The team designed a custom base station to transmit and receive the radio
signals. But that technology conceivably could be integrated into standard
cellular network infrastructure or Wi-Fi routers now commonly used to make
calls."

This is not a cellphone. It is not groundbreaking or new technology. They've
made a radio.

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jankotek
> "power gathered from ambient radio signals transmitted by a base station up
> to 31 feet away"

Seems pretty useless. Better would be to use capacitor and crank handle.

And first GSM phones were also battery free. It was van stuffed with equipment
powered by a generator ;-)

