How gadget in shoes could use foot power to run up cell’s battery
 
  The nightmare of your mobile phone running out of power mid-conversation  could be over. Scientists say they can turn the spring in your step  into the power in your mobile phone by harvesting the kinetic energy  from walking, reported the Daily Mail. Researchersat the University of  Wisconsin have invented a device that, placed in a shoe, captures the  energy of moving microscopic liquid droplets and converts it into  electrical current. Scientists have been working for years on trying to  harness the energy produced from walking, which theoretically is  sufficient to power a light bulb, smart phone or even a laptop. But  until now their solutions have been too cumbersome, or have not produced  enough power to be useful. Now, engineering experts Tom Krupenkin and  Ashley Taylor say they have come up with a technology - known as  “reverse electrowetting” - that can produce as much as a hefty 10 watts  of power. After testing various liquids, the researchers chose a metal  alloy called Galinstan. Used in thermometers, it is similar to mercury  but not poisonous. Two small pouches, placed in the bottom of a shoe,  are filled with the fluid and generate a current whenever they are  compressed by the foot’s up and down motion. Prof Krupenkin said humans  were generally “very powerful energy-producing machines” that could  produce as much as a kilowatt of power while sprinting. Transferring the  energy from a device in a foot to a phone in the hand presents an  obvious hurdle. Rather than plugging a cable into a shoe, the Wisconsin  researchers suggest installing a wireless transmitter in the heel. This  could make radio contact with mobile phone base stations, a task which  typically accounts for most of a phone’s battery use. daily times  monitor
 
source : http://www.dailytimes.com.pk/default.asp?page=2011\08\26\story_26-8-2011_pg9_6