This article first appeared on October 20th, 2011. 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. Researchers at the University of Wisconsin
have invented a device that, once placed in a shoe, captures the
energy of moving microscopic liquid droplets and converts it to
electrical current. 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 motion. According to Professor
Tom Krupenkin, humans are generally “very powerful energy-
producing machines” and can produce as much as a kilowatt of
power while sprinting. But transferring the energy – from a
device in the foot to a phone in the hand – presents an obvious
hurdle. The researchers suggest installing a wireless
transmitter in the heel. The researchers have taken the first
step towards commerciali