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Smart Watch Will Charge Itself Using Heat from Your Skin
- Seebeck 10y agoWow, so great to see this on the front page of HN! I work here, any questions, just ask!
- asadm 10y agoJust skimmed the article. Do you think this tech can be used to power phones too somehow in near future? I always imagined that in future, devices wouldn't need charging.
- Seebeck 10y agoRight now, even a low-end smartphone has power requirements that are about an order-of-magnitude too high for that to work, so we would probably need both better thermoelectrics (we're working on that!) and more power-efficient smartphones to close that gap. The other issue is that since, unlike a watch, you don't "wear" your phone on your skin, we would need a clever approach to collecting body heat, perhaps in concert with some kind of tether.
- jonahrd 10y agoDon't pockets get pretty warm?
- sbierwagen 10y agoIt depends on a temperature gradient. One side has to be warm, the other side has to be cold. If you put it in a pocket it stops generating power.
- rasz_pl 10y agotry 4 orders of magnitude
- bassislife 10y agoIf you are Seebeck, where are Peltier and Thomson? ;)
- z2 10y agoThis looks exciting! Did you consider solar at all, or were you always a thermoelectric group from the start? What was the thought process behind making a watch as your first product?
- Seebeck 10y agoWe've been a thermoelectric company from day one. We'd like to see thermoelectrics not only in wearbles, but also in smart sensors, medical devices, various IoT devices, etc. The watch just seemed like a good place to start because we would hear about people who would stop wearing them because they forgot to charge them.
- jscheel 10y agoAre you confident in generating enough power from the watch body alone, or are you evaluating the strap as a contact point as well?
- hyperpape 10y agoIf it requires temperature differentials so that the cold side of the watch is away from your skin, what happens when the external temperature gets somewhere above 90F/32C?
- Seebeck 10y agoThe technology is able to harness a temperature gradient regardless of its direction, but you're right that the larger the gradient the better it works.
- gnicholas 10y agoDo you expect to see different performance (and therefore adoption rates) in different regions of the US/world? Folks in sunny California saw optimal performance of their Tesla batteries, compared to folks in the chilly northeast—perhaps this is the flip side of the coin?
- rasz_pl 10y agohave you been suckered into equity instead of good wage? A good quality TEG should be able to sustain sharp memory LCD, but is that useful? Who wears watches anymore? People demand connectivity, you can forget any form of active transmission on recovered thermal energy of the body.
- stcredzero 10y agoHow about just operating a sensor, then using skin conduction to network with another worn device with a transmitter?
- rasz_pl 10y agoThe very fact you can buy $0.1 watch(heh) battery that would operate said potential sensor for _two years_ while being smaller makes this startup irrelevant.
- sbierwagen 10y agoHow much power do you actually get out of the TEM?
- blacksmith_tb 10y agoAlso, does the watch charge in any other way? I could imagine using the TEG to top off a normal usb or induction charge. Even if that only doubled the time between charges, that would be a significant improvement.
- jawns 10y agoDoes the side of the watch that's against your skin make your skin feel any different (e.g. colder)?
- deleted 10y ago[deleted]
- fisherjeff 10y agoSo if a human burns ~2000 calories per day and has 1.5-2 m^2 of skin, that means that a reasonable upper bound on (mean) thermal flux density of human skin is around 65 W/m^2. So if a watch makes contact with an area of, say, 2 square inches, that comes out to... 85 mW of available thermal energy? Am I missing something?
- theophrastus 10y agoTo a first approximation that looks fine[1]. To a second approximation one might consider that heat doesn't exit any endotherm in remotely equal surface fashion[2]. And if anything the wrists appear as local minima. [1] https://en.wikipedia.org/wiki/Spherical_cow https://en.wikipedia.org/wiki/Spherical_cow [2] http://i.stack.imgur.com/CsnO5.png http://i.stack.imgur.com/CsnO5.png
- Retric 10y agoAir and clothing vs a metal plate in skin contact makes that slightly less important. The real probably is you probably get 2% efficiency due to minimal temperature differences involved, and people take their watches off.
- rasz_pl 10y agoyou can divide that by ~100, unless you manage to keep temperature difference at 100'
- nickff 10y agoNot a direct response to you, but if you calculate Carnot thermal efficiency with a skin temp of 37 C (likely too high), and ambient temperature of 20 C (probably about right), you get 5.5%.[1] Using this result (combined with yours), the watch has to run on less than 5 mW of electrical energy. [1] http://calistry.org/calculate/thermalEfficiencyCalculator http://calistry.org/calculate/thermalEfficiencyCalculator P.S. It would also be interesting to see how much waste heat is removed in breathing.
- nom 10y ago
- duskwuff 10y ago"Launched […] on Indiegogo" This should be a huge red flag. Indiegogo is notorious for hosting fundraisers for technology projects that are impractical, overpromised, or even physically impossible. Unlike their competitor Kickstarter, Indiegogo performs almost no fact-checking on projects, which has resulted in a number of high-profile scams (like the Skarp laser razor, the DragonFly FutureFon smartphone, and the Triton Gills breathing apparatus). The fact that their fundraiser is operating in Indiegogo's "flexible funding" mode -- which allows them to receive funds even if their goal is not met -- should be an additional warning sign. Real hardware projects have financial targets that must be reached to make them break even.
- rasz_pl 10y agobut a writeup on ieee.org has to mean they are vetted! oh wait, its some blog hosted on ieee domain :), certain Australian is bound to make a video about this.
- devindotcom 10y agoSpectrum is a great publication actually. They cover a lot of stuff fresh out of the lab, but I'm surprised to see this on there. I can't remember the last time I covered something launching on Indiegogo, it always turns on my BS sensor.
- Seebeck 10y agoWoah, we didn't realize launching on IndieGoGo would be such a red flag. Thank you for the lesson learned. Please believe me when I say that we are a real company with real facilities, not a scam. Some other things that may help reassure people: *Our 8-person team has 5 Ph.D.'s, including our founder who did his graduate work in thermoelectrics. Feel free to Google the rest of the team: http://matrixindustries.com/#team *We have funding from Khosla Ventures and 3M, among others *We have real prototypes in the lab right now that generate power when you put them on
- simonbarker87 10y agoTemperature differential is the hardest aspect of this, even if they somehow manage to pipe the heat around the edges any time the user is wearing long sleeves you're going to wreck the heat dissipation - if they could use the top surface of the strap as a heat sink then at least they could get the surface area. Using a Marlow TEG harvester is out of the question as they are too big (and work best at much higher temperatures) but I guess one of the micro scale TEGs made by Micropelt could maybe possibly work - last I checked they were still in beta and when I referenced them in my lit review 7 years ago they were just getting going so it's been a long slog. Even then, as others have said, the harvestable energy from the surface of the skin is so small that it would have to be pretty limited in capability. The best bet would probably be an arsenal of energy harvesters, micro-scale vibration energy harvesters (mems piezo maybe), a magnet in a coil to get walking energy and then also TEG. Could land up being pretty huge. Either way, so long as this isn't a scam, good luck to them.
- ourcat 10y agoI love that they're called "Matrix". Turning us into batteries.
- capote 10y agoWhy don't they just use kinetic energy from the movement of your arm like mechanical watches have been doing for many decades now? Surely it's easier and more of it.
- drzaiusapelord 10y ago>“We see ourselves as a thermal energy harvesting company,” Anne Ruminski, Matrix’s head of engineering told me, not a watch company. Harvesting humans for energy? I guess the Matrix name is fairly tongue-in-cheek here. Curious to know how plausible this is considering how little heat we produce. I wonder if there's a catch like "needs weekly charging" on top of the heat based charging or also has a charger from the kinetic movement of our wrists with the heat charging being a gimmick to get attention and VC money. I'm also concerned this watch will have way too many energy saving compromises to be practical. How often will it pool its bluetooth connection for messages? If it all? The indiegogo page doesn't show any integration with your phone other than fitness stuff, which can be synced infrequently. What about alerts and messages? I don't even see that addressed. Sorry, but its not a smartwatch if it can't integrate with my phone for alerts and messages. Its just a fitness device with a clock then.
- gumby 10y agoPelting devices are pretty expensive and relatively low efficiency. I'm surprised nobody has made a small MEMS oscillator to generate power the same way self-winding mechanical watches work. Perhaps arms smply don't move enough.
- kodis 10y agoI see the same problem here as with self winding watches -- the idea works well enough so long as a person has only one watch which they wear daily. Otherwise, the watch may lose enough energy that it stops keeping time and has to be reset the next time it's worn. Watch collectors can buy "watch winders", a motor driven storage case that will keep their self-winding watches going when they're not being worn. I suppose that now the manufacturers will have to add little heating pads to keep these body heat powered watches going as well.
- beambot 10y agoSeiko built similar thermoelectric harvesters for their (very!) limited run of Thermic watches in the late 1990s: http://www.travisdeyle.com/blog/2007/03/12/thermo-electric-generator-energy-scavenging http://www.travisdeyle.com/blog/2007/03/12/thermo-electric-g...
- digikata 10y agoCitizen, Seiko, Casio all seem to offer a wide range of solar powered watches now. I wonder what the ranges are for energy collected by watches for various thermal, kinetic, and solar methods? I've had a Citizen EcoDrive (solar) for over a decade now.. it just keeps going.. Edit: I see now Citizen also started (1999) and stopped making thermal powered watches... https://en.wikipedia.org/wiki/Eco-Drive https://en.wikipedia.org/wiki/Eco-Drive