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by chris0x00 3192 days ago
So this uses vibrations caused by our voice to change the effectiveness of the antenna to absorb power from the base station right? Base station then interprets the varying current draw as amplitude modulated audio and Bob's your uncle? If I'm correct (no sure that I am) wouldn't this require being pretty close to the base station?
2 comments
jdmichal 3192 days ago
Even if it was transmitting instead of using a side-channel like current draw... With only 3.5 microwatts, the phone would still have to be very close to the base station. As a comparison, "normal" cellphones transmit something around 100 to 1000 milliwatts, so at least 10^5 more powerful.

EDIT: This Wired article has a lot better information:

https://www.wired.com/story/this-cell-phone-can-make-calls-e...

"... Some key components of Talla's phone are housed remotely to save power. A nearby basestation has circuitry for converting and connecting to the digital cellular network, currently via Skype. The prototype basestation uses an unlicensed frequency, limited to low-power transmissions. Because the phone relies on those signals for its energy harvesting, it has a range of just 15 meters from the basestation."

And it looks like they use backscatter, which would be "transmitting" signal and not using a side-channel.

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agumonkey 3192 days ago
Thinking about this I wonder why there's no kinetic charger.
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bduerst 3192 days ago
I'm suddenly picturing a shakeweight or crank cell phone
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agumonkey 3191 days ago
Hehe that would work, and is in store. I had something a little more subtle in mind. I remember Seiko selling "Kinetic" watches with internal counter weights. Maybe it's possible to scale up a similar mechanism in a phone case (granted you accept the doubled width) and enjoy the free energy. Of course this came to mind when running yesterday.

Youtube has some videos about a thing called ampy, a tiny case you attach on you. I'm not sure it made it to market though.

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fish_fan 3192 days ago
I would definitely buy a crank cell phone if I were allowed to clone my sim (for emergencies).
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radarsat1 3192 days ago
https://www.amazon.com/Peach-Dynamo-Charger-Emergency-Supply...

3.99 with free shipping.

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