Sing the body electric: be your own batteries

Paul Raven @ 14-07-2010

Back in the early eighties, my father had a joke he loved to tell non-engineers about the then nascent technology of mobile phones; the punchline sees the customer, heretofore staggered by the miniaturisation of the handset he’s just bought, daunted by the ludicrous size of the power supply.

While those days are long behind us (and my father should be posthumously forgiven, as he started working with computers when they still filled entire floors), the problem remains: the more electronic hardware we want to carry around with us, the more reliable and equally portable a source of juice we need to keep it running. And given that our near future is posited to be crammed with everyware, ubicomp, body area networks and cyberpunkish augmented reality contact lenses, there’s money in being the first to come up with the solution.

Money or military advantage, perhaps… indeed, good ol’ DARPA who are one of the big players in this field, because the amount of hi-tech kit the average soldier has to cart about is becoming a serious issue (not least for the soldiers themselves). Their proposed solution? Scavenge the wasted energy from the human body carrying the kit [via BoingBoing]:

Obviously, our bodies generate heat—thermal energy. They also produce vibrations when we move—kinetic energy. Both forms of energy can be converted into electricity. Anantha Chandrakasan, an MIT electrical engineering professor, who is working on the problem with a former student named Yogesh Ramadass, says the challenge is to harvest adequate amounts of power from the body and then efficiently direct it to the device that needs it.

In the case of harnessing vibrations, Chandrakasan and his colleagues use piezoelectric materials, which produce an electric current when subjected to mechanical pressure. For energy scavenging, ordinary vibrations caused by walking or even just nodding your head might stimulate a piezo material to generate electricity, which is then converted into the direct current (DC) used by electronics, stored in solid-state capacitors and discharged when needed. This entire apparatus fits on a chip no larger than a few square millimeters. Small embedded devices could be directly built onto the chip, or the chip could transmit energy wirelessly to nearby devices. The chip could also use thermoelectric materials, which produce an electric current when exposed to two different temperatures—such as body heat and the (usually) cooler air around us.

It’s a good idea (though it remains to be seen how useful it’ll be; I suspect the efficiency of gadgets will need to increase in order to meet the available energy harvest halfway), but it begs the question: how much wasted energy could we harvest if we were sufficiently motivated to do so? Think of it as a kind of energy freeganism – dumpster-diving for watt-minutes. Wind, solar and tidal power are two taps on the natural world, but what about the environment we’ve made in our own image?

People have thought about harvesting the energy of footsteps to power subway stations; why not do the same with shopping malls (hence ensuring that the energy used is directly proportional to the actual throughout of shoppers)? Might there be some way of harnessing the gravitational flexing of very tall buildings, in addition to covering them with solar cells and heat exchangers and hell knows what else? I reckon we’d be able to think of lots of sources of energy we currently overlook as too trivial, if only we really needed to… necessity is the mother of frugality, after all.


The Diamond Age

Paul Raven @ 27-05-2010

Move over, old-school semiconductors; COSMOS Magazine reports on the coming ubiquity of diamond in small-scale high-tech.


Nanotechnologically self-repairing circuits

Tom James @ 11-09-2009

selfheal_x220Researchers at the University of Illinois have developed a means by which nanotube-filled capsules could repair electronic circuits when they are damaged:

Capsules, filled with conductive nanotubes, that rip open under mechanical stress could be placed on circuit boards in failure-prone areas. When stress causes a crack in the circuit, some of the capsules would also rupture and release nanotubes to bridge the break.

“Many times when a device fails, it’s because a circuit or capacitor burns out,” says Bielawski. “This is critical in situations where you can’t repair it — in satellites or submarines.” To address the problem, engineers currently build redundancy into a system. Self-healing circuits could make devices for remote applications more lightweight, more efficient, and cheaper, says Bielawski.

Consumer electricals have become increasingly cheap and disposable over the past few years. If this technology is adopted widely and improved could it lead to electricals that continue to function well for many decades? It seems unlikely that companies would choose to lose built-in obsolesence as a marketing tool, but if technologies increase in durability and strictly hardware-based improvements tail off (i.e. it becomes more economical to achieve improvements in performance through software tweaks, instead of relying on Moore’s Law) could it be that we find ourselves with the same mobile-phone/$multi-purpose_personal_electronic_widget for many years, which continually repairs and rebuilds itself when damaged?

[from Technology Review][image from Technology Review]


Memristors – is the “missing” fourth electronic component the key to AI?

Paul Raven @ 13-07-2009

I guess I never got far enough with my failed degree in electronics to discover that there’s a fundamental component missing from the metaphorical toolbox.

But apparently there is… or there was. Now, though, the memristor is more than just a concept, and realising it may provide a key to building artificial intelligences… with a little help from slime molds:

Four interconnected things, mathematics says, can be related in six ways. Charge and current, and magnetic flux and voltage, are connected through their definitions. That’s two. Three more associations correspond to the three traditional circuit elements. A resistor is any device that, when you pass current through it, creates a voltage. For a given voltage a capacitor will store a certain amount of charge. Pass a current through an inductor, and you create a magnetic flux. That makes five. Something missing?

Indeed. Where was the device that connected charge and magnetic flux? The short answer was there wasn’t one. But there should have been.

It’s a fairly lengthy article that covers a lot of ground, so it’s hard to summarize with a quote or two. Go read the whole thing; not only is the science itself quite intriguing, it’s also an example of the better sort of journalism that New Scientist puts out.


Top new computer chip material

Tom James @ 15-06-2009

electron_band_bismuth_tellurideResearcher at the Stanford Institute for Materials & Energy Science have developed a new substance for making computer chips that allows electrons to flow without any loss of energy at room temperatures and can be made using existing chip-making technologies:

Physicists Yulin Chen, Zhi-Xun Shen and their colleagues tested the behavior of electrons in the compound bismuth telluride. The results, published online June 11 in Science Express, show a clear signature of what is called a topological insulator, a material that enables the free flow of electrons across its surface with no loss of energy

This is pretty amazing in and of itself, but is not quite a superconductor:

Topological insulators aren’t conventional superconductors nor fodder for super-efficient power lines, as they can only carry small currents, but they could pave the way for a paradigm shift in microchip development. “This could lead to new applications of spintronics, or using the electron spin to carry information,”

[from Physorg][image via Physorg from Yulin Chen and Z. X. Shen]


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