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Body Powered Batteries -- Thermoelectrics 309

An Anonymous Coward writes: "According to this story on Yahoo, the folks at Applied Digital Solutions have "developed a miniaturized thermoelectric generator -- a half-inch diameter ceramic-based `battery' that converts low gradient body heat flow into electrical power." Right now they can power watches or small medical devices. How long before these things can power my handheld?"
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Body Powered Batteries -- Thermoelectrics

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  • It's the first step towards "The Matrix", I'm warning you!
  • Better question. (Score:2, Insightful)

    by jiheison ( 468171 )
    How soon before this technology is co-opted and run into the ground by manufacturers of existing energy technology?

  • I hope it's not where I'm thinking, like how they used to take your temperature as a kid.
  • powering a Beowulf cluster of anything?

    " Dance, you silly little freak, dance!"
  • yAH! (Score:3, Funny)

    by davey23sol ( 462701 ) on Monday October 01, 2001 @03:16PM (#2374955) Journal
    Now your sexual escapades can create REAL electricity.

    ha cha!
    (I doubt this comments applies to any of us...)
  • Matrix (Score:5, Funny)

    by Dark Paladin ( 116525 ) <[ten.lemmuhnhoj] [ta] [lemmuhj]> on Monday October 01, 2001 @03:16PM (#2374956) Homepage

    Now, isn't this how the Matrix started? All these watches and Palm Pilots trying to take over the human bodies for more warmth, covering people at night like kittens on your bed? I can see it now:

    The Future:
    People walk down the streets, scurrying between allyways, keeping out of the light. One man stands in the middle of the street, trying to grasp a piece of cheese left in the alley.

    Before suddenly, he is swarmed by little Palm Pilots, hurtling down the street like killer bees.

    Trinity: Run, Neo! Those are the ones with the ARM processors! They need even more body heat than the old Dragonball ones! And - *gasp in horror* they have wireless antennaes!

    The last thing we hear is one quick "Woah", then the sounds of millions of AvantGo processes launching.

    Of course, I could be wrong.

    • Re:Matrix (Score:1, Offtopic)

      by yellowstone ( 62484 )
      Before suddenly

      Wow! That's quicker than fast!
    • Re:Matrix (Score:3, Informative)

      by NitsujTPU ( 19263 )
      It's always bothered me, in "The Matrix," the way that they harvest humans as batteries. If the AI was all that intelligent, they would have known that the energy investment in farming humans would be greater than the output. YES, the human body does output X joules of energy, but in order to output that energy in a harvestable form an even greater amount of energy has to be invested. Without the sun's energy all of life on earth would die, farming like that would not be practical.
      • I was bothered by the same thing.

        I figured that there was some residual programming in the computers to help humans, so they went out of their way to use people, despite the inefficiencies such a system implies.
      • Re:Matrix (Score:3, Insightful)

        Of course the Matrix doesn't work exactly right. Any decent scientist could come up with dozens of things that can't quite work in the real world, but that's not the point.

        IT'S A MOVIE.

        As far as I'm concerned all the details of the world outside the matrix are just fantastical psuedo-science to justify the story they want to tell about and inside the matrix. It's a story about preceptions of reality and the nature of intelligence. The details of the technology aren't important to the points they are really trying to make. Get over it.
        • Re:Matrix (Score:2, Funny)

          by Anonymous Coward
          Oh, sure....that's just what THEY want you to think!
      • I always got the feeling that the so called AI in The Matrix was actually more of an Artificial Malevolence. While it could have (nearly) exterminated humanity at any time, it chose to go use extraordinary means to keep them under its heel for some revenge / retribution / punishment motive that a true AI would not have deemed a logical choice.

        Basically, it was insane. And it reminded me a lot of the AI in Harlan Elison's "I Have no Mouth and I Must Scream."

      • The only things that I'd add into the whole mess:

        1. Didn't Morpheus mention something about "a certain form of fusion"? I'm assuming something biological is required for that to work. (Hey, it's called science fiction for a reason.

        2. Without sunlight, we can assume that most of the life on Earth got zapped (humans always watching out for themselves). From there it would have been pretty logical to go from "destroy humans" to "capture/harness for fusion system/keep trapped in system". (Maybe the Matrix requires some sort of neural net to run - aka, the machines *need human brains to keep their own programs running*, which makes them even more dependant on us as we are on machines (which lets Morpheus's comment on the irony of humans using tools make sense).

        You'd have to assume that by the future, other sources of power (nuclear, oil, etc) are also depleted (which may have launched the whole humans vs AI war to begin with - maybe they didn't *want* to have the energy star label on their monitors...)
    • A new kids toy B.I.O Bugs [] was first advertised on the premier of the new Star Trek series. These BEAM robot toys seek out IR signals to 'feed' on, but there are other such experimental robots that convert sugar to electricity. Consider a toy of this sort with thermolytic batteries where it seeks out body heat to 'feed' on. I can see it now. "Jonny, don't let that bug shove his antena up your..." Oh, damn!

      OK, this technology has potential but it could also make for some really creepy toys.

    • One thing I hated about The Matrix was that stupidity about dying for real just because you died in virtual reality. It's just complete and utter crap. The worst thing that would happen is you'd go into shock.

      Other problem: what do you mean you can't pull the plug without winding up dead? Think about it: my computer doesn't explude just because I unplug the ethernet connection. I'm sure you could easily invest some time in making the Matrix interface safe.

      Of course, without these major flaws, the movie is no longer an "adventure", since there's no danger.

  • by n8willis ( 54297 ) on Monday October 01, 2001 @03:16PM (#2374957) Homepage Journal storage.

    What happens when you take your wristwatch off for 8 to 10 hours? Sure, generating electricity from body heat is fine when its a pacemaker... take that off and you're likely going to miss it before the eight hour mark.


    • by Anonymous Coward
      seiko has a bunch of kinetic watches that go into a low power mode when they stop moving. The hands freeze, but time is still kept. when it realizes that it is being moved again, it puts the hands in the correct place and continues on it's way. I believe the latest ones will keep time for up to a year without movement.
      • by whydna ( 9312 )
        I have one of these; they're pretty neat. First of all, they can maintain time for about 2 weeks without being worn/moving. They store energy in a small capacitor, but when it gets low it only ticks every other second to conserve power. It's pretty sweet
    • no no no, that's why the company will sell you a low grade bed side heater box than you put all your goodies in.

      think ways to get you to spend $$ if you don;t have to feed it batteries.

    • IBM is already working on a magnetic form of RAM called MRAM which won't need a constant flow of electricity to store information. I'm not sure if or how it would be used in such PDA's but it's a possibility. ra m/
    • Existing "automatic" mechanical watches generate energy with an eccentric rotor, and store it using a spring. I don't see why the same tried and true storage can't be used.
    • "Is he dead?"

      "Yes, see, his watch stopped."
  • they have had this kind of stuff for watches for a long time.

    you will not be able to power your handheld unless it is somehow connected to your skin... and it probably still wont work unless you are soaked and holding a bare electrical cord.
    • thermoelectric batteries are totally new...
      You're talking about kineto-electric batteries - the ones that charge when you shake them or otherwise move them about.
      • by mmontour ( 2208 )
        thermoelectric batteries are totally new...

        Link to the Citizen Eco-Drive Thermo [] watch...

        "Eco-Drive Thermo converts the temperature difference between the user's body and the surrounding air into electrical energy to power the movement. [...] The original Eco-Drive Thermo was launched to great acclaim at the 1999 Basel Show."

        Don't know if it's shipping to consumers yet, but the technology's been around for a while.
  • Now you can pleasure yourself with no physical motion, nor any batteries to change!
  • other factors? (Score:1, Redundant)

    by FortKnox ( 169099 )
    I dunno about you, but I don't sleep with my watch on, nor do I wear one in the shower. Does it store energy very well? What about outside tempature fluctuation? How well does it handle in the winter? Does the amount of fat on your arm matter?
  • microns? (Score:5, Informative)

    by egomaniac ( 105476 ) on Monday October 01, 2001 @03:19PM (#2374975) Homepage
    I assumed the release was just written by a clueless person when I saw "10 micron amps". Poor fool just meant "10 microamps".

    Then later down I see a quote by the *chief scientist* saying that they plan to develop a battery "capable of generating 3 volts of electricity with 10 microns".

    Maybe I'm just an idiot, but the only definition I know of "micron" is a unit of linear measure. I have no idea how this would relate to anything electrical. I'm still cautiously assuming they meant "microamps", but does anyone have any other ideas?
    • maby 3 volts with 10 microns of serface area? Dunno how feasable that is, but thats how I read it.
      • I had similar thoughts, but a micron is a one-dimensional measure. Certainly couldn't be measuring surface area, let alone volume, and 10 microns is *really* small for a device like this in any case.

        It mainly scares me because this is a press release, rather than an article, and the quote is by their *chief scientist* who hopefully should know better. You'd think a press release would get proofread, but maybe not...

    • Probably just misquoted by a tech-clueless reporter. They should have said microamps like you stated.
      • Check the article: "SOURCE: Applied Digital Solutions, Inc."

        That's right, this is not a Yahoo article, despite what the Slashdot summary says. It's a press release by the company in question. It really scares me to see glaring, repeated factual inaccuracies in press releases by tech companies...
    • Well it is written that way on the press release [] on their website as well.

      I thought perhaps it was just a different meaning for "micron" that I had never heard before, but a quick search on google for "micron amps" [] turns up no relevant references. More than likely, some clueless PR person "corrected" the what the scientists had given him.

      Of course, as important as this is you'd think they'd have one of the developers check the final draft of the release, but guess not. Technical illiteracy strikes again.
    • by MarkusQ ( 450076 )
      I believe the issue is thickness; at least, from basic physics I'd expect voltage to be linked to the thickness (and the difference in temp. between the two sides) and amps to be linked to area (and the degree of coupling).

      Thus, it would be meaningfull to talk about any of these or any products (e.g., area x thickness --> volume, voltage x amps --> watts, etc.) and micron amps would be some sort of effectiveness metric (backed, presumably, by some assumptions about body temp, room temp, etc). If this interpretation is correct, for device rated at x-and-so micron amps, total power would be proportional to total area.

      On the other hand, it might just be a typo.

      -- MarkusQ

  • You have to wonder about the technical insight of the company, when their own press release (this IS a press release, not a news story, after all) when they report "1.5 volts of electricity with 10 micron amps". Is that a "microamp"? Next time, folks, let's get the spelling and grammar straight before you talk to the world.
  • by TaleSpinner ( 96034 ) on Monday October 01, 2001 @03:20PM (#2374981)
    How long before these things can power my

    Screw that. How long before they can power an
    artificial heart!?

    A completely self-contained, reliable, artifical
    heart available off-the-shelf and requiring no
    external battery pack or management would be a
    sea change in modern medicine. Jean-Luc Picard
    lives! Wonder what brand he uses?

    • obviously nothing of this solar system. Who in their right mind would buy anything from Earth? You want to goto the Blahblah galaxy and get all your hardware there. They are known for their blahblahs and blah.

    • A completely self-contained, reliable, artifical
      heart available off-the-shelf and requiring no
      external battery pack or management would be a
      sea change in modern medicine.

      I can just imagine the Tech Support Call for this one...

      "Press 1 if you're having trouble installing your BeatFree Artificial Heart. Press 2 if your Heart will not start..."

      Of course, that'll lead to all kinds of 911 calls...

      "Help! My husband's heart isn't beating!!!"
      "Ma'am, please calm down. If your would turn your husband over and look at the Service Tag on his left ass-cheek...."
      "Ok, Ok! Here it is... 615-CU-OEM-5YE"
      "Ma'am, I'm sorry but you'll have to call the vendor for support. You're husband has an OEM heart."

      Or even better...

      "Sir, your heart is working fine. You'll just need to replace the power supply!"
      "How would I do that?"
      "Well, take you wife into the bedroom...."

      Seriously, this type of thing has been mentioned in numerous sci-fi novels as an imminent invention. I would love to get a wristwatch display installed underneath the skin on my left wrist, with luminous hands which glow through the skin. It would be cool, it'd never run out, you'd only have to set it once, you could upload new hand-designs onto it, and you'd only see it when you needed it. If it broke, it's a small incision, but it never breaks because it's under the skin. Sign me up!

      • >I can just imagine the Tech Support Call for this one...
        >"Press 1 if you're having trouble installing your BeatFree Artificial Heart. Press 2 if your Heart will not start..."

        And of course, those with a Microsoft ArtificalHeart XP would be paying for a SERVICE and wouldn't actually OWN their hearts.

        Caller: Oh NO! My husband's heart just stopped! Please help! What do I do?!
        Microsoft Rep: Well, did he just install anything new or make any large configuration changes recently?
        Caller: Well, he has gained a lot of weight lately... with the holidays and all...
        Microsoft Rep: Yes, I see, that would do it. You need to apply for a larger license. Perhaps a 5-seat license. How much does your husband weigh?

    • See the Economist article (22SEP01 issue), "Atom Heart Father". It's available in your library or on-line either free for subscribers or for a $3 one-off reading -- not worth three bucks, if you ask me.

      Basically, an artificial heart is being developed which works on the steam engine principle. Rather than water/steam, another solution is used which will boil around body temperature and, even more importantly, condense close to that temp as well, allowing for the return stroke.

      Neat stuff. Too bad it's "premium content" only.


  • I didn't see an efficiency of the energy conversion listed in the article. I wonder how these compare to photovoltaics.
  • All options (Score:3, Interesting)

    by Docrates ( 148350 ) on Monday October 01, 2001 @03:21PM (#2374989) Homepage
    As always my memory fails me, but I read in Wired Magazine, about a year ago, about this guy that stored the energy generated by your footsteps and then used it to power all sorts of devices. It turns out he was doing pretty well, but I don't know what came out of it.

    Now, if we were to identify a real demand for personal power generation, I'm sure there's a combination of strategies we could use, like those footsteps, body heat, chemicals, heck, even blinking!.. If you consider how many calories are burnt every day by our bodies in order to make it work, and how much energy is released in all sorts of ways, I'm sure we could power our cellphones and PDA's forever.
  • scary stuff? (Score:2, Interesting)

    by jptxs ( 95600 )
    small devices, with their own power which can be placed on/in any person and run off of them for an indefinite amount of time... tagged at birth, tracked in secret... never off the screen for even a nanosecond...
  • ...for instance, pacemakers and artifical organs. The latest breed of artificial hearts has to be charged through the skin several times a week. With a few improvements to this new design, the mechanical heart could be TRULY self-contained. A very practical and useful application if you ask me...
  • This sounds like all those sci-fi terrorists.

    "Don't shoot me. If my heart stops, this thing will explode."

    On a more serious note, this thing would be great for my wife. She has had to have numerous pieces of equipment plastered to her to monitor her EKG. That stuff is heavy. I hope this gets into production soon.
  • I just had a funny idea for a short story: Someone with a lot of electronics on them dies because they didn't eat breakfast and they were sucked dry of energy by their "personal helpers."

    Well, if someone writes that, email it to me. :)

  • by exceed ( 518714 ) on Monday October 01, 2001 @03:22PM (#2375000)
    This article at NY Times [] has an interesting article on other methods of using body energy to power things.

    It mentions methods such as cranking and pumping, and of course, stride (i.e. stride-powered watches). One company created a human-powered electricity generator which creates electricity by hand pumping. If you pump one of these for a few minutes, it can power a cell phone for around 20 minutes.
    • It mentions methods such as cranking and pumping...

      I once had a hand powered torch (flashlight); probably late 70's or early 80's. You squeezed the handle in to spin up a flywheel attached to a dynamo to generate electricity to power the bulb; the handle sprung out again when released. Pumping the handle a few times to get the flywheel up to its top speed took a few seconds, and you got around 10-15 seconds of light out of it before it needed to be pumped again. The only catch was you could only use it for short durations before your hands became too sore to drive the torch!

      A clockwork mechanism where you wind up a large spring with a handle would be much more ergonomic, and using LEDs as the light source should make it long-lasting. The "Dolphin" torches (waterproof, using a large rectangular 6 volt battery) would seem an ideal form-factor for a clockwork torch.
  • by hillct ( 230132 ) on Monday October 01, 2001 @03:23PM (#2375008) Homepage Journal
    And you thought falling into a frozen lake was a health hazard before... just wait until you have an artificial heart run by your body heat.

    Even after the EMTs pull you from the lake they couldn't restart your heart for at least half an hour until your body temperature increased. Bad news.

    Seriously, it doesn't mention what's the minimum temperature the device requires.

    • And you thought falling into a frozen lake was a health hazard before... just wait until you have an artificial heart run by your body heat.

      Even after the EMTs pull you from the lake they couldn't restart your heart for at least half an hour until your body temperature increased. Bad news.

      Good point. If my heart ever fails and they offer to put in a body-heat-powered heart, I'll just tell them "No thanks, I'd rather die now than risk that frozen-lake scenario."

  • Not much info (Score:4, Insightful)

    by Shotgun ( 30919 ) on Monday October 01, 2001 @03:24PM (#2375010)
    How expensive is the material to create these small batteries? It's a ceramic, so would it be feasible to create bricks which could be used to line or even build smokestacks? Could this be a replacement for solar cells (the article indicates a temperature gradient as a power source, and those are everywhere). Obviously, these don't produce much energy, but ceramics are notoriously easy to mass produce and fashion into all sorts of artsy shapes.

    • make ceramic heat sinks that absorb the damn heat from CPUs and power the whole house. I know that if I had one of this on my little Alpha UDB (space heater) I wouldn't have to worry about my $90/mo electric bill. :)

      At least the little box would be worth more than the MP3 server it is now.
    • Re:Not much info (Score:2, Insightful)

      by NCamero ( 35481 )
      According to Thermodynamics, the maximum amount of energy that could be obtained by such a device is related to a few things:
      1. The temperature difference between skin contact area and the air.
      2. The surface area of the device.
      3. The ability of the skin to supply power by reheating the chilled area in contact with the device.

      The efficiency of thermoelectric devices was pretty low in my engineering school days. I would assume they have increased like that of solar cells has.

      And such devices could be used in general for smokestacks and other (waste) heat sources. The problem is that the property of insulation is really desirable for such things. And thermoelectric devices like to conduct heat so that more energy can be extracted.
    • Similar systems are available commercially. Here [] is one that:

      [...]will produce a maximum power of 12 watts. This system contains a unique DC/DC boost voltage converter and charge control adjustable from 5 to 14.8 V.and can be used to charge a battery and provide over 200 watt-hr per day of energy for various uses. It can be installed in 6" and up, firetube type heating systems with a minimum 125,000 btu. rating and is completely hidden with-in existing equipment.
    • Ceramics is likely just the closest familiar idea. The overwhelming majority of the good bulk thermoelectrics (and all of the nanostructured ones I'm aware of) are made of semiconductors. Not Si or GaAs, but more exotic ones like bismuth telluride (Bi2Te3), bismuth antimony (Bi-Sb, an alloy), &c. In general they come from the bottom right f the periodic table and are pretty toxic and expensive to make -- about equivalent to the CdTe in solar cells.

      That said, there are already thermoelectric devices being used to reclaim waste heat in power plants. Also, the NASA Voyager space probes use thermoelectric devices coupled to a radioactive Pu source to generate their juice - mostly because thermoelectrics are pretty reliable devices.

      More applications are in cooling -- using the opposite physical effect for localized cooling, especially for applications where vibration or noise are problematic. Laser diodes and some other IC devices use thermoelectrics for cooling (or at least temperature regulation). Larger applications, like household refrigeration, aren't practical (despite the environmental benefits) because the efficiency is ~10%, compared to 30% or so for your fridge and ~90% for the enormous air conditioners in office buildings.
      Current research is largely driven by electronics folks -- wouldn't it be nice to get rid of those noisy, bulky fans in your computer?- and is focusing on, of course, nanotechnology as the answer for improving the thermoelectric figure of merit.

      Is it really obvious this is the subject of my (ongoing) chemistry PhD work?
  • by RobertFisher ( 21116 ) on Monday October 01, 2001 @03:25PM (#2375020) Homepage Journal
    Nicholas Negroponte [] of the MIT Media Lab has a related article [] online on this topic.


  • by DudeTheMath ( 522264 ) on Monday October 01, 2001 @03:26PM (#2375029) Homepage
    Gee, I only need 33,333,333 of those advanced 3V, 10u-amp "batteries" to generate a kW. Put on the suit, hook it up to the microwave, and 20 minutes of dancing gives me dinner!
  • Use poor people to solve California energy crisis!
  • How long will it be before this technology can power a self contained artificial heart? If you can keep one of those running 24x7 on body heat, that'd be a huge step forward. The next step past that would be having the heart change its level of pumping based on how much you're exerting yourself and you could have a device that could feasibly be left in a human for the rest of his life AND have that span be 5-10 years or more.
    • by Arlet ( 29997 )
      The problem is that you need a temperature gradient. Inside the human body there is hardly any gradient, so this wouldn't work without part of the device being outside the body. Even then, I am sure there's no way this method comes close to generating the power needed for an artificial heart.
  • With the mention of wristwatches I'm reminded of a Seiko watch I saw advertised a few years ago that had some kind of internal mechanism for capturing kinetic motions (via ratchets?) into a windup spring that subsequently would provide sufficient electric power to run the wristwatch.

    So I'm wondering how much electric power can be reasonably gotten from each source.

    You'd have to set limits, so the thermoelectric generation doesn't consider an extreme case of someone naked sitting in artic temperatures full encased with thermo electric generators sucking off the terrific temperature gradient at their disposal. Likewise, a kinetic watch that weighs many kilograms and requires that it be shaken vigorously and constantly at 2 Hz in order to provide many watts is kind of a ridiculous proposition as well.

    So what's next - hemoelectric generators powered by little turbines in major arteries?

    • Actually, I own one of those (Seiko Kinetic) watches. The one I have does not store power by winding a spring, but rather by charging a small capacitor. With a fully charged capacitor, the watch can go on for about 3-4 days without any movement what so ever - a great plus for someone as lazy as I am ;)
    • URL for that watch (Score:2, Informative)

      by dbCooper0 ( 398528 )

      Shockwave Version here [], and Non-Shockwave version here. []

      Another post in this thread correctly states that the energy is stored electrically in a capacitor, not a spring.

      I had a summary of the concept all set to submit, but like an idiot I tested my url with the same browser session I was submitting with, and lost it! No time to re-type it. The links tell all.

      My kid in the Navy brought a fake one home last winter, and I'm going to take it apart to see how close the knock off is to the real one :)

  • I think some of the techs in my building could be our backup UPS if they designed these into s3x toys....

    also, how would these things work for those of us who are cold blooded (son of two lawyers)?
  • by hoggoth ( 414195 ) on Monday October 01, 2001 @03:29PM (#2375057) Journal
    I can see it now:

    The Boston Marathon becomes a Beowulf Cluster!
    WWF wrestlers finally produce something worthwhile!
    Japanese Corporate Sararymen power their buildings by energy generated during morning calesthenics!

  • by AsbestosRush ( 111196 ) on Monday October 01, 2001 @03:30PM (#2375062) Homepage Journal
    Hearing aids. Not quite as mission critical as a heart, but still good to use as a sort of field test, IMO.
  • Now all we have to do is pump up the voltage! Then cybernetically implant a cell phone in/on you, earbud installed into your skull, NO better yet, hardwired into your brain, microphone grafted to a tooth, and you are WIRED BABY!!

    Patch a PDA into it, figure out how to pipe the display to your retina, and we're Cyborgs! All wired, all the time.....

    Now where does the antennae for 802.11 go? WAIT!! I know just the place!! :)

  • by Amazing Quantum Man ( 458715 ) on Monday October 01, 2001 @03:33PM (#2375083) Homepage
    Just stack one of these babies on top of a P4! That amount of heat'll generate enough electricity to solve California's power crunch!

    Tags included for the humor impaired to comply with the Americans with Disabilities Act.
  • Since everyone's brought up the matrix, it's obvious that the movie industry thought of this idea first and will be the appropriate content holders. Everyone will have to pay a tax to generate body heat and will no longer be allowed to share body heat without paying royalties.
  • Admittedly this post is about passively generated electricity, but there's also been some work on electricity generated by harnessing activity such as walking []. This company [] for example, has been using peizoelectric devices to generate a few milliwatts of power from walking/running activities. For the most part the energy produced is insufficient for anything other than trickle-charging batteries.

    For most of us here on /. putting little piezoelectric generators under each key of the keyboard, and under those mouse buttons would beat those peizoelectric shoes anytime!
  • Since this works off of body heat, this requires you to burn more calories! So now the overweight nerds out there can all have a GREAT excuse to (a) buy more gadgets and (b) not excercise!

    "Aww, but I am exercising, I'm playing VirtualQuakeVII on my Palmiot! You have any idea how much processing juice that takes? I can feel myself getting thinner by the minute!"
  • a lot of people keep saying, 'oh no, if you have a self powered artificial heart and swim in freezing water near the polar cap, you're dead.'

    ever notice how much more heat you generate whilst you sleep or excerise? just store the extra and use while you're 'swimming with polar bears', because i know just how popular it is to swim with polar bears.... sheesh.
  • by morcheeba ( 260908 ) on Monday October 01, 2001 @03:49PM (#2375190) Journal
    >How long before these things can power my handheld?

    Yes! They can provide 100's of watts!

    These have been used for years to power deep-space satellites such as Pioneer 10 (solar power tends to not work too well when you get away from the sun). Plus, no moving parts to fail. They use radioactive decay as their heat source.

    They use plutonium-238. It half-life is 87.8 years and emits primarily alpha particles, a non-penetrating type of radiation which requires little shielding.
    Here's a good page from nasa [] and another from the doe []

    Power ranges from milliwatts in 1964, to "multi-hundred-watt" in 1977 (the sole power source for voyager), to 208 Watts electrical (+4500W thermal!) in 1990, to 507 Watts (electical) in 1997.

    Practically, there's that whole radiation thing, plus some costs to enrich the material, and then also disappating the thermal energy released (it operates on a gradient, so you've got to have a cold end to counter the hot end)
  • All of this has amusing similarities to the wonderful 6th grade science experiment of making a potato powered clock. You know - just shove the wires into a standard red russett and watch with amazement as the clock goes. Same principle, really, save that potatos are lumpy, brown, relatively sedentary items that seem to be more agreeable when fried, and people are... oh, wierd.
  • I see a double requirement here folks which can make such a tech. not much usable.

    In order for those devices to function they need body energy. The way to get body energy is to "exercise". In order for us to keep exercising, we must "eat".

    Now tell me, is an already over-weighted, under-exercised society, are really willing to appreciate such a device, when it will constantly remind them to "wake-up and move" when it is low on battery? I think not!

    We are a society looking for comfort, those "body-energy-devices" won't appreciate such an attitude.
  • Ever since i actually tried using laptops on my lap for any reasonable period of time I decided that they really should run cold, using my body heat for power...
  • <soccer mom voice> You don't have a fever, Timmy. You're just a little thermo-electrically abundant right now. </soccer mom voice>

    But seriously, will Tylenol® makers Johnson & Johnson now be at odds with the energy companies? I wonder how long before Informed Experts appear on TV commercials to let us know that a fever is a good thing, or the D.E.A. shows up at raves to pass out free thermoelectric generators with handfuls of PMA...

  • by tcc ( 140386 ) on Monday October 01, 2001 @04:15PM (#2375370) Homepage Journal
    That's a few watts... you'd need something to convert BioGasses into energy...

    ... and a lot of beans...

  • We could have clothes that generated power integrating these things into them. Then we could plug in various devices into a plug in our clothes, like handhelds, watches, cellphones.
    But wait, is the price that these things will be selling at be feasable? Why not make panels out of these things, put them across a black panel surface and use them as solar panels that take in the heat from the sun and produce energy, but will it produce more than solar panels? will it be cheaper?

    ideas = thoughts = mind = thinking = knowledge, control of one = control of the others

  • The upper bound on efficiency of these things is governed by the Carnot cycle limit; so for a temperature gradient from T2 down to T1, your upper bound is (T2-T1)/T2. So, I the power generation is limited by the surface area of the thing (governing the wattage of heat going through it) and the temperature gradient itself.

    I guess if we assume a skin temperature of 34 celsius (307 K), and an ambient temperature of 20 C (293 K), then our efficiency is bounded by about 4.5%. Given that we dissipate on average 64W/m^2 at idle, and a "fingernail" sized device (1.5 cm^2), we should have about 0.001 W available to us, or 0.4 mW assuming 100% of Carnot cycle efficiency. At 1.5V, this gives a maximum current output of 0.27 mA. Since they are getting about 10 microA, then we can assume they see an efficiency of about 4% themselves. So, it seems like there's room to grow!

    Maybe they'll be able to power those PDA's after all!

    There's a quick discussion here [] with regards to human-body-power available for wearable computing.

    Also, there's another company that builds thermo-ionic power generating chips (cleverly named PowerChips) called Borealis []. They see them being used as a second-stage on typical gas turbine/etc.. generators. They claim to see 20% efficiency wrt the Carnot cycle limit, a few orders of magnitude better than most thermo-electric (Peltier based) generators.

    BTW: All these calculations are very "back of the envelope"!

    • I dunno. Those Borealis people sound like a scam. They claim a new type of electric motor, a new type of solar cell, a new thermoelectric cooler, and a really big magnetite deposit ready to be mined. And somehow none of these things is actually in production.
  • Wow, just think what this could mean for the personal vibrator industry!
  • Great potential... (Score:2, Informative)

    by Bagheera ( 71311 )
    This is one of those technologies that could have great potential both in the biomedical field and in the portable device field. Unfortunately, the article doesn't give much detail - and has a couple of strangely glaring errors (10 microns?)

    From what I remember of RTGs (Radio Thermal Generators - like those used on Deep Space probes) rely on a temperature differential to generate power. With a body powered unit, you'd be looking at drawing power from the difference between human body temperatute and the ambient temperature outside.

    If it's 98 degrees outside, hope you have -real- batteries around to provide power.

  • by Anonymous Coward
    I will be glad to host your power needs. I'm a large male with virtually no body hair. Order now for prime power locations:

    Rolls on Back of Neck: $0.25/hr
    Underarms: $0.50/hr
    Between Butt Cheeks: $5.00/hr
    Back Side of Balls: Call for latest price.

Make it myself? But I'm a physical organic chemist!