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Portables Toys Hardware

Crowdfunded 'PowerWatch' Runs on Body Heat, Never Needs Charging (engadget.com) 81

Engadget reports on a new watch that suggests the possibility of a future without chargers: This thermal-powered wearable doesn't need one -- it gets energy by converting your body heat into electricity. It's been a year since I saw an early prototype of the PowerWatch -- a smart(ish) watch that tracks basic fitness metrics. Now, the self-proclaimed energy-harvesting company is finally ready to ship PowerWatches to the early adopters who backed its Indiegogo campaign...

Because its functions are pretty basic and its LCD screen is relatively low-powered, it doesn't take too much electricity to keep the watch running... The PowerWatch can not only tell the time, set alarms and timers but also track your activity and sleep... Matrix co-founder Douglas Tham said the PowerWatch will keep running for up to 12 months if you don't wear it, and a PowerSave mode kicks in to conserve energy by killing non-timekeeping functions.

Crowdfunded 'PowerWatch' Runs on Body Heat, Never Needs Charging

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  • And (Score:4, Informative)

    by Anonymous Coward on Saturday November 11, 2017 @01:39PM (#55531577)

    It's also been a year since the debunking video existed [youtube.com]

    • yeah, I can't imagine the physics behind this work... and you'd have to wear it tight as shit..

      • All these 'energy harvesting devices' cheat. They find a microuniverse and suck the energy out of it. Eventually the microuniverse being energy sucked implodes with the death of all its inhabitants and they just move on to a new one. The bastards.

        They're also the reason you need to wear a hat, coat and scarf inside your Tardis despite setting the climate control to 'temperate'.

        • "All these 'energy harvesting devices' cheat."

          I got a watch 50 years ago that harvested its power, not from the heat, but from the movement of my arm.
          And it still works and doesn't need any upgrades or patches.

          • I got mine, a Casio, for ~$30, several months ago, and it has both a battery and a this thing called a 'solar cell.' Turns out, most people need light to read a watch face, and will be outside at some point during the three months or so that it might take to discharge the battery...it can also charge just fine indoors, using ambient light. Like a solar calculator, doesn't need much to run...

      • Doesn't the efficiency of conversion depend on the temperature difference between the source and the sink? Which, compared to a classical steam engine, is going to be not much Fahrenheit (in metric: bugger all Celsius).

        Thermodynamically speaking, heat to something else is uphill; it's possible but a lot harder than the other way round.

      • yeah, I can't imagine the physics behind this work... and you'd have to wear it tight as shit..

        Even then, it won't work for people with Raynaud's Syndrome [wikipedia.org]. My spouse has Raynaud's, and in the winter her hands (and feet) are so cold that there would be a negligible thermal gradient.

    • The biggest trouble with this seems to be the difference between what it's priced at and what it's worth. A $199 price tag on something worth, maybe $70 over the expected usage of the product (guessing at time saved estimating calories spent doing other things of potential value after 30ish years of use), is a tough sell.
    • by Anonymous Coward

      I don't need youtube. I radiate approximately 100W. You have about 20 ft^2 of skin, figure about 1.5 in^2 for the watch, that means you can get (with 100% conversion) 0.5 milliwatts. Forgive the non-metric units -- I am an American. It's going to be tough to charge a battery with that and power the watch.

      Personally, i think you could do better with self-winding. I could do the potential energy generation for a rotating weight but I will leave that someone else.

  • by no-body ( 127863 ) on Saturday November 11, 2017 @01:47PM (#55531607)

    what are cool guys/gals doing then with such a device?

  • I find it dubious that low-value heat would be more suitable for powering a watch than, say, a flexible solar cell in the watch strap.
    • by msk ( 6205 )

      My solar-powered, WWV-listening Casio analog/digital watch has been running for eight years and these days remains on an always-shaded windowsill for a week or two at a time.

      While a body heat-powered watch is nifty, mine is niftier.

      • Those things seem to last forever. Presumably eventually the Lithium Ion battery will need to be replaced due to this effect

        https://en.wikipedia.org/wiki/... [wikipedia.org]

        Loss rates vary by temperature: 6% loss at 0 C (32 F), 20% at 25 C (77 F), and 35% at 40 C (104 F).

        Still mine's still going strong after 7 years.

      • And my Seiko Kinetic has been running continuously for almost 10 years not needing any www connection to keep good time, nor battery changes, winding etc. All it needs is that I wear it at least 10 days every month.

        • And my Seiko Kinetic has been running continuously for almost 10 years not needing any www connection to keep good time, nor battery changes, winding etc. All it needs is that I wear it at least 10 days every month.

          Or one special Saturday night every now and then.

        • But it's doing a whole lot less than your thing is.

          This thing has an LCD display and active senors that seem to be constantly running. Both of which are far bigger energy sinks than moving a mechanical watch hand once a second.

    • I find it dubious that low-value heat would be more suitable for powering a watch than, say, a flexible solar cell in the watch strap.

      Exactly. I would guess that an "invisible" solar panel behind the watch face or even a small disc a few millimeters wide could generate more energy from ambient light in an office than you could ever generate from waste body heat.

    • I would assert that some type of flywheel that uses the motion of one's arm, similar to self-winding watches, would bring in more energy over time, and one can use a self-winding watch case to keep the watch at full charge when it is not in use.

      For body heat to work, the watch needs a hot side, and a cold side... and a reverse Peltier junction. However, the surface area of the watch just doesn't seem up to the task, especially if the watch is worn in a jacket.

      I would rather go with a solar panel (perhaps t

      • The flywheel is mechanical, though, and probably breaks more easily than a (solid-state) solar cell. A solar cell really seems ideal for this, not to mention its very high possible output compared to any other energy scavenging scheme.
        • I would agree that because it is a moving part, it eventually may have issues. However, there are many self-winding watches out there that have long lifespans. Seiko, Bulova, and other brands have been making self-winding watches for many years, and their failure mode rarely is the mechanics involved.

          • I don't question that it's possible, but at what cost (and price to the customer)? The solid-state solution will be cheaper than a solution that is both mechanical and reliable. It will also offer more power to the device.
    • Re:Huh? (Score:5, Informative)

      by hey! ( 33014 ) on Saturday November 11, 2017 @06:32PM (#55532695) Homepage Journal

      Watch geek here.

      A watch doesn't take much power at all. Digital watches can run for years on tiny, tiny batteries. The classic Casio F-91w, also known at the "al Qaeda watch [wikipedia.org]" runs for seven years on a CR2016 cell which delivers 100 maH at 3V: in other words roughly 1000 joules. That translates to a power draw of 5 microwatts.

      Now a smart watch is going to draw a lot more power than that, because it has a processor and probably a part time on luminous display to power. But "a lot more than 5 microwatts" leaves a lot of headroom.

      Now there are mechanical watches that are powered by photovoltaics, but combining this with a display could be tricky. But another possibility might be a small dynamo powered by wrist action. Of course non-electronic "automatic" watches have been doing this for decades, but every since Seiko introduced it's "kinetic" watch movements in the mid 80s there have been quartz watches powered by mechanical generators with capacitive storage. Currently Seiko and Swiss manufacturer ETA produce "mechanical quartz" movements.

      The question is whether you get more power out of a mechanical generator or a thermoelectric generator. I believe Bulova introduced a thermoelectric quartz watch in the 80s, but it never caught on, where as kinetically powered and photovoltaic powered quartz watches remain quite popular. Undoubtedly the technology has improved since then.

      • Even if you're going for low power "non-smart" watch, chances are that a solar cell would be much cheaper to build and integrate. They're a "less-specialty" item than a thermoelectric generator nowadays. And the comparison is better for a solar cell even when comparing it with a TEG for a high temperature differential. I don't even need to see the price/power difference for body heat levels.
  • by guruevi ( 827432 ) <(evi) (at) (evcircuits.com)> on Saturday November 11, 2017 @02:08PM (#55531693) Homepage

    When this first came out, the makers promised a fully fledged smart watch. Now this thing could easily be powered for 5-10 years with a button cell and many âoeregularâ models like it have existed for at least a decade.

    Watch the thing dying on everyone after 13 months, right outside the warranty.

    • by AmiMoJo ( 196126 ) <mojo&world3,net> on Saturday November 11, 2017 @05:56PM (#55532605) Homepage Journal

      There are many bullshit claims on their page. "Accurate calorie count" via thermal management... No, skin temperature is not correlated with calorie burn to any useful extent.

      They are extremely vague about how they will monitor your sleep quality too. It's not really a smart watch either, it doesn't have any connectivity.

      My guess would be that it's a basic LCD watch with step counter built in. The calorie burn and sleep monitor are faked from the step counter data.

      • by Nethead ( 1563 )

        And who the hell wears a watch to bed? I don't even like one when I'm typing. Besides, I have a phone that tells time. I haven't had a need for a watch in over a decade.

  • by TheOuterLinux ( 4778741 ) on Saturday November 11, 2017 @02:23PM (#55531763)
    that you wind only every few days or so (some five on a single wind)? No batteries. Tells time. Crazy." **Rolls eyes and looks at his grandfather's "antique" watch.**
    • âoeFar out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-two million miles is an utterly insignificant little blue green planet whose ape-descended life forms are so amazingly primitive that they still think [fitness tracking] watches are a pretty neat idea.â -- Douglas Adams, Hitchhikers Guide quote in context. George Orwell would think it's funny. "Arms bending and st
    • My grandfather gave me this crazy high tech invention:

      https://en.wikipedia.org/wiki/... [wikipedia.org]

    • No batteries. Tells time. Crazy.

      So what you're saying is it is completely and utterly worthless. Time is free. You right now are in the vicinity of at least two devices that can tell you the time.

      A watch must do more or show off. They are either a fashion accessory or a functional gadget. Being able to tell time is it's least desirable feature, which is kind of why the more money you spend on a watch the less likely it is to keep as accurate time as a $10 Casio.

  • It's solar, it get NIST time, sure body heat charging would be fine, but as far as I'm concerned solar is proven.

    • as far as I'm concerned solar is proven.

      [citation needed]

      I live in my mother's basement, you insensitive clod!

  • What if you're dead? Does it still work?
  • The only reason to buy a watch in 2017 is as a fashion accessory or if you're hiking/camping. And if you're doing that then why aren't you buying a wind up or if you're really well to do one of those expensive ones that 'wind' while you move?
  • https://www.watchonista.com/ar... [watchonista.com]

    This talks about two watches that are powered by body heat, in the 1980s. I remember one in the ate 1980s for a digital watch powered by body heat.

  • Seems to me if humans as batteries worked in The Matrix, that means it would have to work in real life. Or do I have that backwards?
    • The Matrix would make more sense if the captive humans were being used as computation devices. Brains manage full consciousness in only a few Watts. Apparently the original script did say that but they thought it would be too hard for the audience to understand.

  • My dad had a "self-winding" watch (analog, obviously) that drew its energy from your motion. This was probably around 1970. I guess this new watch is the same thing, only for people who don't move around much.
  • by Neuronwelder ( 990842 ) on Sunday November 12, 2017 @12:34PM (#55535783)
    IF this article is true. It's finally using science to do something positive for us. They could progress this heat energy to cell phones and more. It's very depressing and sickening to see science to track us, know what we are doing, hide extra charge on bills, and software to "look over our shoulders" to "ensure" we sweat hard every second at work, One example: You would not believe how sophisticated, they track truckers! Have respect for them and stay out of their way of their way! Today's truckers almost literally drive with a gun behind their heads. I have many other examples of negative software but I don't want to drone on.

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