London: A device that fits inside a pair of shoes saves the energy generated when someone walks and successfully uses it to charge watch batteries, scientists say.
The shoe insole was created after scientists at the Center for Research in Advanced Materials (CIMAV) in Mexico decided to "capture" the energy produced by people walking.
They designed a pill-shaped cylinder adapted to a shoe in order to store the mechanical-vibrational energy the person generates when walking.
With the captured energy they have been able to recharge clock and AAA batteries. The prototype designed by CIMAV adapted the 'pill' which has a diameter of two inches and a thickness of three millimetres to the sole of a shoe.
Abel Macias Hurtado, head of research and specialist in materials science, said that the pill is a device called piezoelectric measuring pressure, force and acceleration, placed in the sole, and by means of a circuit converts mechanical energy into microwatts; once connected to the batteries, it was tested with good results.
Piezoelectric is a term that comes from pressure and electricity. When walking, mechanical force is generated which is "captured or harvested" to generate the energy that is "stored" in the pill for further use.
Hurtado said the prototype was implemented in an ordinary shoe with a wide sole.