
Battery-free Game Boy runs forever - lelf
https://techxplore.com/news/2020-09-battery-free-game-boy.html
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wk_end
> Most importantly, it impersonates the Game Boy processor. Although this
> solution requires a lot of computational power, and therefore energy, it
> allows any popular retro game to be played straight from its original
> cartridge.

It's not clear whether they're emulating the Game Boy in software and this is
just running on an ARM or something, or if this is an FPGA-based hardware
recreation (or even custom silicon, since schools can have the resources), or
if they actually harvested the hardware from an old Game Boy. Aside from the
custom silicon, none of these would be maximally energy efficient (the real GB
would've been done on ancient processes), so it's exciting to think about what
a battery-less gaming system could be if the market demanded it.

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derefr
You could get pretty close by doing a static recompilation of Gameboy Z80
software (ala
[https://andrewkelley.me/post/jamulator.html](https://andrewkelley.me/post/jamulator.html))
to target an ESP32-based system.

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xwdv
Oddly enough there was a Gameboy game in Japan with a sensor on the cart that
required sunlight to play. The intent was to get kids to be outside more.
Guess they didn't think about a standard desk lamp.

~~~
j4nt4b
Standard desk lamps wouldn't work for Boktai, but a UV light always maxed out
the meter. Kids are way less likely to have one of those lying around.

~~~
cptskippy
What kind of UV lamp? Sounds like it could potentially be dangerous to cheat.

~~~
j4nt4b
Well, seeing as it was attached to a keychain...

What kind of sunscreen are you using right now, by the way? Sounds like it
could potentially be dangerous to go outside.

~~~
cptskippy
Someone could buy a UV-B Lamp off ebay and do some serious damage.

~~~
xwdv
To do their in-game enemies mostly.

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Avtomatk
Why did they put the solar panels on the front? I personally prevent sunlight
from reaching the screen due to the annoying reflection, putting it on the top
and back seems a better option.

I found it ingenious that they used the console's own buttons as an additional
source of power (I don't know of any console that does the same)

~~~
chomp
Probably because it can barely power itself as it is - it sounds like it needs
to stop for a second every 10 seconds so it can harvest power.

~~~
willis936
If this is true then the save of the installed cartridge is in danger. Gameboy
cartridges are saved in volatile SRAM that run off of watch batteries when
unplugged from the console. When plugged into the console the SRAM is supplied
power by the console. If you had a watch battery die while plugged into this
perpetual gameboy you would never be able to save the game. You’d have to
leave the cartridge plugged into the gameboy to keep the state.

~~~
dole
The lag is due to it dumping state before it switches power sources, then
reloads.

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nanomonkey
Reminds me of Playdate [[https://play.date/](https://play.date/)], a handheld
game device, that had a crank on the side. Unfortunately, I don't think you
could charge the batteries by winding the crank.

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pwinnski
"Forever" so long as solar and kinetic inputs are effective.

