Published on June 26th, 2011 | by Jo Borrás


Coming Soon: the Laptop You Power by Typing

June 26th, 2011 by  

Solar powered laptops are barely here, and — if the hype is to be believed — already headed for obsolescence.

Why so?  Because a team of researchers at Australia’s Royal Melbourne Institute of Technology (RMIT) have successfully demonstrated a new, “nano-scaled” piezoelectric film’s capacity for turning mechanical pressure into electricity — bringing the (admittedly geeky) dream of perpetually-charged laptop batteries one small step giant leap closer to reality.

Piezoelectricity“, as a phenomenon, was discovered in the 19th century and is currently employed in things like electric cigarette lighters.  Piezoelectric materials (like crystals or ceramics) have been studied thoroughly over the last century, but research on thin films is relatively new, according to the team’s research lead, Dr. Madhu Bhaskaran.  “Our study focused on thin film coatings, because we believe they hold the only practical possibility of integrating piezoelectrics into existing electronic technology,” she explains.  Dr. Bhaskaran hopes to implement her research findings into consumer electronic form factors on a wide scale — but doesn’t stop there.  “The power of piezoelectrics could be integrated into running shoes to charge mobile phones, enable laptops to be powered through typing or even used to convert blood pressure into a power source for pacemakers — essentially creating an everlasting battery.”

Now that the experimental films have proven to produce quantifiable electricity, the only road-blocks to industry acceptance will likely come from the material’s initial cost and resistance from the manufacturers of conventional “rare-Earth” battery packs.

Source:  Advanced Functional Materials (journal), via Gizmag.

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About the Author

I've been involved in motorsports and tuning since 1997, and write for a number of blogs in the Important Media network. You can find me on Twitter, Skype (jo.borras) or Google+.

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  • John

    Multiplying a couple of estimates together is hardly a deep dive into mathematics, it’s just basic numeracy. Energy harvesting is a topic where too often wishful thinking overrides realism. I have shut down projects where regrettably that realism was absent.

    My figure was for the oldish laptop I’m currently using – it’s what the power gauge is reading. I could imagine the power consumption being reduced to a tenth or less, say to that of a PDA-type device, smart phone or MP3 player. This would make energy harvesting easier: now we are only three orders of magnitude away, i.e. we need to type at an average of 1,000 keystrokes per second. It helps.

    However, reducing the power requirement now makes it easier to achieve satisfactory operating life using a battery: in our example, it increases battery life by a factor of ten, from 4 hours to 40 hours. A further factor of ten reduction in consumption gives a battery life of 400 hours; somewhere near this point power stops being a major issue!

    Kindle-type devices with passive E Ink screens already have a battery life in weeks if not months, with no need to type continually on some Keyboard of Death.

    Anyway, eReaders and iPads don’t have keyboards.

    The difficulty with the laptop application is that there is not enough power going into the keyboard by typing, however it is harvested. Our fingers simply don’t deliver enough power, just a millijoule or so per keystroke. And the lower the power consumption of the computer, the more attractive (i.e. smaller, cheaper, longer lifed) batteries become.

    This is the bind in which energy harvesting technology so often finds itself. On one side, the energy available in the environment tends to be rather too scarce to be useful, that is, it is too widely dispersed and therefore has to be gathered over too large an area or volume to be convenient and cost effective.

    On the other hand, if the power requirement is lower, then batteries start to look more attractive. Usually they can deliver more power at less cost in a smaller package. But they do need to be recharged or changed periodically.

    There are definitely niches where energy harvesting works very well, though they are quite rare. Wireless sensors are an example, as there is no wire to power the device. But the power consumption of modern chipsets can be so low that the sensor may have served its purpose or become obsolete before its battery is flat.

    Anyway, the abstract refers to ‘integrated microscale energy scavenging systems’; ‘micro’ i.e. millionths, very little. I’d guess that early applications for the thin piezoelectric films that RMIT University is developing are more likely to be as integrated sensors for motion detection and other sensing, and maybe for generating a few microwatts for very low-powered circuits.

  • John

    No. No, no, no, no, NO!

    First, Dr Bhaskaran has not invented a product for charging laptops or anything else. What she has done is develop a nanoindentation technique to assist in the characterisation of thin piezoelectric films. No doubt this is very useful research, but it is nowhere near being a product.

    Next, a typical keyboard key force is 45g and key travel is about 3.5mm. The energy from a single key press is therefore F x s = 1.5mJ. My laptop is currently consuming about 15W. Therefore, assuming all the energy from each keystroke is converted into useful power, which it can’t, I would need to average 10,000 key strokes per second. I can’t type that fast.

    Even with reduced power consumption and stiffer keys with greater travel, it is clear from this simple sum that this is several orders of magnitude away from a feasible invention.

    For example, if the keys had 35mm of travel and required a key force of 450g (i.e. about one pound-force), and the laptop used only 1.5W, it would require ‘only’ 10 keystrokes per second, still assuming no losses. But at 1.5W, my existing batteries would last 40 hours instead of 4.

    The energy harvested from the environment (after all the losses) must exceed the power consumption of the device.

    Many energy harvesting ideas fail as soon as this basic arithmetic is done. Too often there is simply not enough energy in the environment available to be harvested. If there were, the world would be unbearably noisy, shaky, lossy, windy, hot, bright or whatever.

    Reducing the device power consumption of course reduces the energy that needs to be harvested. However, this then makes it easier to achieve acceptable life from batteries. Thus there is a rather narrow window of opportunity for energy harvesting where it is not more cost effective, compact and reliable to use batteries instead.

    I am not against energy harvesting in principle. Sometimes there are reasons why energy cannot be stored (e.g. plants that are subject to explosive atmosphere regulations) and battery changing or charging is difficult, that create an overwhelming case for energy harvesting.

    There are some good products where energy harvesting works well: PV powered calculators, torches with solar battery chargers, bike lights with dynamos, where the power requirements and duty cycle match the available energy. But in practice, good opportunities are scarce and most do not stand up even to basic engineering scrutiny. Like this one.

    • Anonymous

      Wow, that looks like a pretty powerful debunking of its usefulness & promise
      (unless i am missing something). Thank you for that.

      • Jo Borras

        I think what you’re missing is that power consumption of laptops is dropping with new display technology, and that “laptop” doesn’t necessarily equate to “2GHz processor w/ 2GB RAM …” etc., and could well mean E-Ink display running a simplified Linux/Chrome OS with drastically reduced power consumption compared to current “overkill” devices.

    • Jo Borras

      VERY well-said and a thorough deep-dive into some of the maths involved, but I think you’re overstating the power requirements of a usable device. The latest E-ink devices, for example, are certainly proving their use in a number of Android and e-reader systems, and measure power usage in millivolts, which would certainly change the equation, I would think (though, I could be wrong).

      I’m thinking this would be less a conventional laptop and more of an e-ink device that could also save word processing documents, spreadsheets, etc., and serve primarily as an e-reader/commuter tool that’s a little more type-friendly than the current generation of eReaders and iPads.

      What do you think?

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