
With Nanogenerators, Cellphone Use Powers Itself - Parbeyjr
https://edgylabs.com/2016/12/15/nanogenerators-power-cellphone/
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legulere
You only get tiny amounts of energy out of energy harvesting in general. The
press release [1] links to a video that drives a black and white LCD display
[2]. You really should look at that video to see what the tech can do. You
can't power smartphones with that.

Still energy harvesting is pretty interesting for e.g. sensors. There already
are zigbee light switches that work through energy harvesting (e.g. [3])

[1]: [http://msutoday.msu.edu/news/2016/flexible-device-
captures-e...](http://msutoday.msu.edu/news/2016/flexible-device-captures-
energy-from-human-motion/)

[2]:
[https://www.youtube.com/watch?v=TS2thXzbSek](https://www.youtube.com/watch?v=TS2thXzbSek)

[3]: [http://www.nxp.com/video/nxp-enocean-energy-harvesting-
wirel...](http://www.nxp.com/video/nxp-enocean-energy-harvesting-wireless-
switch-at-ces-2014-zigbee-nfc:ENOCEAN-ENERGY-HARVESTING)

~~~
brudgers
I'd think of as energy recovery more than energy generation. The analogy would
be to regenerative braking on an electric vehicle. Thermodynamics still
applies, but the device becomes more energy efficient at the macro scale. Here
the relationship to energy recovery seems to be that what is displayed on the
screen is related to the amount of swiping.

I'm not sure it's going to change the world, but I'm not certain it isn't
worth pursuing either.

~~~
legulere
The power generated by this is probably several magnitudes smaller than what a
phone uses. What's the use when your phone gets e.g. 0.1% more energy
efficient?

Regenerative braking makes sense because it's a lot of energy and you can use
the motor as a generator.

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teilo
Energy harvesting is essentially heat reclamation.

This makes for a trivial smell test for claims such as these: Think about how
much heat is generated as you discharge your phone battery. Now imagine how
long it would take you to generate that same amount of heat by swiping on your
screen.

Cars, for instance, generate a LOT of heat when you hit the brakes. This makes
them an excellent target for energy reclamation.

Now if they can reclaim the heat radiated from a CPU/GPU, that would we worth
talking about.

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gubby
I find it exceptionally unlikely that the statements in this article are
correct. I suspect a phone with the screen lit uses somewhere in the range
0.5-2W continuous. The amount of energy you'd get from a light touch on the
screen is, at an educated guess, in the order of a few millijoules at best.

