Tiny ARM-Based Sensor System Makes Battery Replacement Obsolete 96
An anonymous reader writes "University of Michigan researchers have crammed an ARM Cortex microcontroller, a thin-film battery, and a solar cell into a package that is only 9 cubic millimeters in volume. The system is able to run perpetually by periodically recharging the on-board battery with a solar cell (neglecting physical wear-out of the system)."
THIS is how you get "infinite" battery life (Score:5, Informative)
I think this is the first time I've ever actually seen a legitimate claim of a device drawing less power than it can charge from ambient sources.
Re:THIS is how you get "infinite" battery life (Score:5, Informative)
Never had one of those nifty solar calculators?
Re:neglecting physical wear-out (Score:2, Informative)
Use a capacitor instead of a battery (Score:3, Informative)
For something that small, a capacitor would be better than a battery. Better utilization of short peak light to stored energy. Short term high current draw (e.g. for a transmitter). Much (much) longer life than a rechargeable battery. It could run for hundreds of years.
Re:Bogus logic (Score:5, Informative)
"Neglecting physical wear" when it comes to batteries is like saying "This car runs forever (neglecting its need for fuel)"
No, neglecting physical wear is like saying this car will constantly fuel itself, so it can run forever, until the engine or other components physically break down hundreds of thousands of miles later.
Re:neglecting physical wear-out (Score:5, Informative)
And lack of sunlight....
RTFA: "...periodically exposed to reasonable lighting conditions, even indoors"
A more modern equivalent (Score:3, Informative)
That's called an automatic movement. They're quite common.
Less common is a watch like this one, [amazon.com] which is a quartz analog watch powered by five independent, shock-dampened micro-sized motors. It does chrono, world time, and alarms. Every night it syncs with the FM radio signal from the atomic clock in Fort Collins, CO (or at least it tries to, several times over several hours) so it always has the correct time. AND the entire face of the watch is a solar panel, which it uses to charge a battery, allowing it to essentially run forever (much like the device in this story).