Wearable Power is a hot topic in the Wearable Electronic field. A recent announcement made by a team of researchers at the University of Michigan puts this topic back into public view.
Their concept, a Electricity – generating knee brace is a wearable mechanism that works much like regenerative braking charges a battery in some hybrid vehicles, said Arthur Kuo, an associate professor of mechanical engineering at the University of Michigan.
“We’ve demonstrated proof of concept,” Kuo said. “The prototype device is bulky and heavy, and it does affect the wearer just to carry. But the energy generation part itself has very little effect on the wearer, whether it is turned on or not. We hope to improve the device so that it is easier to carry, and to retain the energy-harvesting capabilities.”
First test showed the energy amount that can be produced is around 5 watts on average and can be up to 13 watts by brisk walking., enough to deliver power for all of your personal electronic devices at the same time.
A practical use in sight could be to operate a portable GPS, a cell phone, a motorized prosthetic joint or an implanted neurotransmitter. Stylish and fashionable integration into street wear might be a bit further off into the future but the potential of this concept is undeniable.
Wearable power generators that eliminate the need of bulky and heavy batteries have been on the research agenda since the early days of Wearable Electronic.
A similar Wearable Power concept that has been around for a long time is the Power Generating Shoe investigated by different groups at MIT. The idea is to transform the theoretically huge forces generated by walking or running into electrical power.
The most investigated technology for power generating shoes involves the use of piezoelectric materials. Those materials give off electrical power when deformed like stretching or compressing. The advantage: only very few mechanical moving parts are involved which allows a robust system design. The disadvantage: the power output of such system is too low to be of practical use at this moment.
Another Wearable Power concept is under investigation by Researchers at Michigan Technological University, Arizona State University and NanoSonic Inc.
This team is working on harvesting the ambient energy of walking and carrying a backpack. The backpack has straps made of a piezoelectric material that can convert the mechanical strain on the straps into electrical energy that may power or recharge portable electronics.
Using a backpack to generate wearable power was taken up by a team of biologists at the University of Pennsylvania as well. They created the Power generating Backpack that converts mechanical energy from walking into electricity – up to 7.4 Watts.
The ‘Suspended-load Backpack‘ is based on a rigid frame pack, much like the type familiar to hikers. However, rather than being rigidly attached to the frame, the sack carrying the load is suspended from the frame by vertically oriented springs. This movement is used to generate power which is then stored in batteries.
Last but the most interesting technology for wearable power are flexible solar panels. Products using this technology are already commercially available such as bags ranging from outdoor gear like backpacks to fashion bags.
Even clothing with flexible solar panels reach the fashion market. The energy performance of flexible solar cells are good enough to charge most of our hand held devices like audio player and cellphones. The ‘limitation’ of this wearable power source is the sun factor. No sunshine means no electricity generation.
But even this limitation makes flexible solar cells a very interesting option to ‘top-off’ the power of portable devices when away from the power grid.
Generating power for e-textiles and small electronic devices for our daily needs is one of the most challenging but will also be one of the most rewarding areas in the realization of truly wearable electronic products.
To speed up and focus the research efforts in finding the best solution for Wearable Power, the Department of Defense Research and Engineering set out a bounty of $ 1 Million for the team or person that comes up with the best solution. The runner up will still be awarded $ 500K for the efforts.
The submission date ends in fall 2008, it is still time to start looking for THE killer solution of Wearable Power.