Wearable technology has been around for some time now but most electrical forms have one common unifying limitation, their batteries. These batteries tend to have limited capacities that directly impact their long-term use and once drained, the tech just becomes a fancy piece of jewelry.
Several talented individuals around the world have been developing methods of harvesting power from an unlikely source - you. They range from tapping into your biochemistry to using your own motion to generate enough electricity to power electronic devices.
If this technology can be mastered we may see a time when batteries, at least for small personal devices, are a thing of the past.
1. Bionic Power Generates Power from Walking
Initially designed and built for use by the U.S. and Canadian Armies, Bionic Power has created a wearable technology, PowerWalk, for charging batteries. They believe that this technology will have great utility in disaster zones and remote working sites as well as recreational activities.
PowerWalk is a light-weight piece of kit that generates electricity from the mechanical movement of the wearer whilst walking. This is much the same way as regenerative braking systems work.
Generated power is then used to recharge the equipment's Li-ion (NiMH) batteries.
2. Piezoelectric Quartz Watches Are Still Some of the Best
Piezoelectric Quartz Watches, sometimes termed 'automatic quartz', have been around for some time now but remain one of the best, and stylish, wearables that generate power.
They work by generating electricity using a piezoelectric quartz crystal and self-winding rotor. Electricity is generated from a rotating pendulum attached to a 'large' gear and small pinion setup that spins the pinion at high speed when the wearer moves.
This motion is then translated to a miniature electrical generator that charges either a capacitor or rechargeable battery.
3. Solar and Motion Generating Cloth Could be the Future
Researchers at the Georgia Institute of Technology are developing a purely motion-generating electricity harvesting textile. Technically, it is bi-generational as it also integrates solar generation.
Apart from direct solar generation, the textile generates electricity from the motion of the wearer from triboelectric nanogenerators. These generators work by combining the triboelectric effect and electrostatic induction to generate electricity from any movement that agitates the textile.
4. Could Mini-Solar Cell Textile Be the Future of Wearables
Researchers around the world, including in China, are developing polymer solar cell textiles that are able to generate small amounts of electricity. Like other entries on this list, successful creation of this kind of material could make batteries a thing of the past.
Invented by Huisheng Peng, professor of macromolecular science at Fudan University in China, the polymer has an energy-conversion efficiency that varies less than 3% after bending for more than 200 cycles, researchers said.
5. Thermoelectrical Power Generation Makes Electricity From Your Own Body Heat
Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have been working on a power generating wearable technology that harvests your body heat to make electricity.
Using flexible thermoelectric (TE) power generation, it could be used to power future wearable devices.
6. iTeng Could Be the Future of Medical Devices
iTeng is another form of triboelectric nano-generation that harvests energy from the principle of static electricity. One interesting application of iTeng is that it produces electricity to power small medical devices like heart monitors.
This kind of device has massive implications for future implantable devices and could, perhaps, be used in the future to self-power healthcare monitoring systems.
7. Yarn-like Rechargeable Zinc Batteries Are Almost Here
Researchers are currently developing a form of rechargeable zinc-ion battery that comes in an elastic yarn form. It is able to generate electricity whenever the yarn is bent, stretched, washed or cut.
This material could, conceivably, form the basis for future 'smart clothes'.
8. Electric Eel Inspired Fiber Capacitors
Chinese scientists have managed to produce a synthetic fiber that mimics bio-electrical abilities of electric eels. These stretchy eel-inspired fibers could be used to make self-powering wearable devices of the future.
Being capacitors, they are able to store electrical charge on the surfaces of the conductors and can capture and release energy much more quickly than batteries can, although they usually store less energy than batteries do.
Other researchers have found a way to print capacitors directly onto textiles too.
9. The Future of Shoes Could be Triboelectric
An obvious application of the principle of wearable power generation is to integrate the technology into the soles of your shoes. This is exactly what researchers at the Georgia Institue of Technology succeeded in creating.
They were able to put piezoelectric technology into the heels of shoes that could harvest energy as the wearer walks or runs.
Tests of the technology have shown that this a TENG-based shoe insole could produce a maximum output voltage and current density reached up to 220 V and 40 mA, respectively.
10. Your Sweatband Could Generate Electricity in the Future
An interesting potential future wearable technology could generate electricity as you sweat at the gym or on a hot day. Sweating releases lactate which can be used as 'fuel' molecules by enzymes to generate a small electrical current.
These enzymes can be stuck onto nanotubes and formed into biofuel cells. These can then be woven into garments such as headbands and wristbands which can then readily generate enough electricity from chemical reactions with sweat lactate to power devices, like a watch.
Other researchers have a similar concept using bacteria instead.
11. You Could Power Devices With Your Underwear or Trousers in the Future
Researchers have developed wearable piezoelectric energy harvesters that could be worn on your elbow or knee joints or trousers and underwear. Such wearable technology will enable the user to generate electricity whenever they move.
Scientists note that we might not want to make these kinds of generators too efficient. Less is more, as the adage goes. MIT materials scientist and engineer Canan Dagdeviren explained that "it might do so by placing more of a load on the body, and you don't want it to make you tired".
So there you go 11 of the best wearables in development that could create power.