Tiny ARM-Based Sensor System Makes Battery Replacement Obsolete

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)."

Comments

THIS is how you get "infinite" battery life

[Shadow of Eternity]

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

[Anonymous Coward]

Never had one of those nifty solar calculators?

Re:THIS is how you get "infinite" battery life

[nicknamenotavailable]

Batteries have a limiting lifespan.

If they used a capacitor instead, this device would run virtually forever.

Place this in a solid glass marble, and it might last forever too.

Re:THIS is how you get "infinite" battery life

[Firehed]

If this device is as smart as TFS suggests, it can probably use more than 10 characters. Hell, something that size (9mm^3) could be, uh, discreetly placed to take pictures and send out the real thing!

Not that I would ever condone or support such an act.

Re:THIS is how you get "infinite" battery life

[kju]

Why on earth would they want to attach an ARM to a sensor

Because it can be done.

What do you gain by lower power requirements? You probably didn't RTFA, but at least take a look a the picture in full resolution (http://ns.umich.edu/Releases/2010/Feb10/MINISENSOR.JPG). The solar panels are already included in that tiny device, and it powers the ARM already. Decent processing power is good, think encrypting the - probably sensitive - data in the sensor.

Re:THIS is how you get "infinite" battery life

[vertinox]

Batteries have a limiting lifespan.

If they used a capacitor instead, this device would run virtually forever.

Place this in a solid glass marble, and it might last forever too.

Note:

When something is sold as "infinite" or "forever" it doesn't actually have to meet its claims.

It just has to last longer than the person who paid for it.

The person who inherits its will think its quaint and let their kids break it.

Re:THIS is how you get "infinite" battery life

[Anonymous Coward]

> It just has to last longer than the person who paid for it.

Wrong! It just has to last longer than the person who sold it ;-)

neglecting physical wear-out

[nurb432]

And lack of sunlight....

Re:neglecting physical wear-out

[ChunderDownunder]

Dude, time to step out of Mom's basement!

Re:neglecting physical wear-out

[Yosho-sama]

Even without direct sun, solar cells still function, just at reduced capacity, mmmkay?

Re:neglecting physical wear-out

[TubeSteak]

And lack of sunlight....

RTFA: "...periodically exposed to reasonable lighting conditions, even indoors"

So let me see if I get this straight

[Anonymous Coward]

If we ignore wear-out, battery replacement is obsolete.

Uh hum.

Re:So let me see if I get this straight

[arielCo]

“Our system can run nearly perpetually if periodically exposed to reasonable lighting conditions, even indoors [...] Its only limiting factor is battery wear-out, but the battery would last many years.”

By the time the battery wears out, you have gotten a few years of data; then you toss away the tiny thing.

Bogus logic

[DavidR1991]

"Neglecting physical wear" when it comes to batteries is like saying "This car runs forever (neglecting its need for fuel)"

I didn't think the ability to charge batteries was ever the problem - it's the fact that the innards of the batteries themselves slowly degrade and eventually become unusable

Re:Bogus logic

[Rei]

> It's not really that slow, either. The claim that the batteries will run perpetually is RIDICULOUS. Slashdot occasionally makes me feel ill.

Occasionally? You have a stronger stomach than I, it makes me want to vomit most of the time.

Vomit? It makes me want to cut out my spleen with a dinner fork and stomp on it with high heels!

By the way -- did you know that people who use lots of hyperbole are worse than Hitler?

Re:Bogus logic

[rockNme2349]

"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:Bogus logic

[InterruptDescriptorT]

STOP in the name of Godwin's Law!

Before you reich my heart?

Solar Geek device is doomed to failure.

[Kenja]

The Day Star burns us, we dont care that it can recharge our toys. We're still not going outside.

Use a capacitor instead of a battery

[macemoneta]

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.

Oh God

[TopSpin]

then you toss away the tiny thing

Right. So it goes from some interior space where light is good, but not daylight, to some landfill where it is exposed to the Sun. What was 'worn out' now has an abundance of photons and reactivates. It's not happy about ending up in Fresh Kills with the other 500,000 discarded and reanimated sensors. Eventually they unify into a vast, angry landfill monster and wade across the water to crush New York.

Please do not contribute to garbage self-awareness.

Re:So what the hell does it DO?

[karnal]

It probably just sits there and senses how much juice is left in the battery, and then lets the solar cell charge it.

A more modern equivalent

[PCM2]

That's called an automatic movement. They're quite common.

Less common is a watch like this one, 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).