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Hardware Technology

Researchers Develop a Non-Toxic Thermoelectric Generator For Wearable Tech (ieee.org) 27

Researchers from the University of Massachusetts, Amherst, have developed a new method of harvesting electricity from body heat to power wearable devices. "The new, wearable thermoelectric generator is also sourced from non-toxic and non-allergenic substances, making it a viable candidate for wearable technology," reports IEEE Spectrum. Furthermore, "the substrate on which the generator is built is plain old cotton fabric." From the report: More precisely, it's a vapor-deposited strip of cotton fabric -- coated with a material called, brace yourself, "persistently p-doped poly(3,4-ethylenedioxythiophene)" a.k.a. PEDOT-Cl. One end of the fabric touches a person's skin and is thus at a person's body temperature. The other end, ideally, is exposed to the open air. The greater the difference in temperature between the two ends, the greater the electrical output. [...] The innovation here was to vapor deposit their polymer only onto the surface of the cotton fibers -- and not soak the entire cloth in the polymer.

By keeping the semiconducting material on the surface, they could allow for charge to flow through the material while still thermally insulating one end of the generator from the other. This stems from the competing demands of a good thermoelectric conductor. The ideal material must somehow keep one side hot and the other side cold -- in other words, the material must be thermally insulating. However, it must at the same time conduct electrons. Electrical current needs to flow, or it's not a very good generator. With this vapor deposition trick, she says, "The polymer can be really, really electrically conductive." And PEDOT-Cl fills that bill. However, because the polymer is only coated on the outer surface of the cotton fibers, the bulk of the material (i.e. the cotton) is still able to perform its thermally insulating role.
The research has been published in the journal Advanced Materials Technologies.
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Researchers Develop a Non-Toxic Thermoelectric Generator For Wearable Tech

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  • by Anonymous Coward

    Let the CEO of the company wear that material on his ball sack for 25 years and we'll see what happens.

  • by markdavis ( 642305 ) on Wednesday February 06, 2019 @08:00PM (#58081662)

    You could wear THIS monster: https://spectrum.ieee.org/imag... [ieee.org] in order, under ideal conditions, to generate "millivolts" :) I don't think that is going to work out for smart watches or most devices. Seems like just adding a solar element on the strap and bezel would work better in most cases. Still, kinda neat.

    Maybe add that thermal stuff, plus solar, plus WiFi harvesting, plus a kinetic weight spinner and together it could give a 1/100th charge (and cost three times as much and weigh four times as much). I think I will just throw my wearable device on a wireless charger once a day for a short time.

    • Re:Milli! (Score:4, Interesting)

      by Immerman ( 2627577 ) on Wednesday February 06, 2019 @10:24PM (#58082054)

      Keep in mind that, as an end user, you don't actually care about the voltage, it's the wattage that matters. If you can generate 1 million amps at 1 milliVolt, then you've got 1kW of power - the rest is just a matter of stepping the voltage to the desired levels.

      Granted, that's pretty unlikely, but I hate hearing people cite information that's so incomplete as to be basically useless.

      • Close to useless. The voltage is actually pretty important as it is in a sense a measure of efficiency, S = dV / dT (see Seeback Coefficient) [www.fzu.cz]. The power is scalable by surface area. For reference a 1 inch square TEG will give you maybe 7W @ 300C/30C (572F hot vs. 86F cold).
        • Note that your formula does not actually involve voltage - only the ratio of voltage differential to temperature differential. Now, it's probably safe to assume the voltage given is actually the differential between the ends of the thermocouple, but without being given the corresponding temperature differential, the information is still useless. (You probably also want to know the absolute temperature, since S for a given thermocouple may vary with absolute temperature even if the temperature differential

  • by fahrbot-bot ( 874524 ) on Wednesday February 06, 2019 @08:25PM (#58081734)
    ... wearing that through airport security.
  • How does it work during a lightning storm?
  • 'More precisely, it's a vapor-deposited strip of cotton fabric -- coated with a material called, brace yourself, "persistently p-doped poly(3,4-ethylenedioxythiophene)" a.k.a. PEDOT-Cl.'

    Better that, than a p-doped poly fluorinated-indium laminar extrusion - a.k.a. PEDO-FILE.

  • Vibrators.

  • Oh if this isn't the first step to the Matrix I don't know what is...

    Step 1: Generate power from human bodies to operate wearable technology.
    Step 2: Create AI to inhabit wearable technology (probably to help you decide what type of chicken to buy).
    Step 3: Find Neo...

    • I'll offer another film-based analogy:

      Dr. Kynes: It's a high efficiency filter and heat exchange system. Perspiration passes through the first layer, and is gathered in the second, Breathing and walking provide the pumping action. ... With a Fremen suit in good working condition, life can be sustained for weeks, even in the deep arctic, sire. With your permission. (motions to Paul)

      Dr. Kynes: You've worn a heatsuit before.

      Paul Atreides: No.

      Dr. Kynes: Your suit is fitted antarctic fashion. Who told you how to

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