Walk and Charge

Consider this scenario. You’re out on a morning walk, and

as you walk, your shoes generate power by which you can run your cellphone,

handheld, Walkman or MP3 player, without batteries. Sounds out of a James Bond

movie? It’s now in the realm of the possible.

Two technologies have been tested so far to convert energy

used in walking into electrical power, and more are on the anvil. The first one

uses piezoelectric material, which is either incorporated in discrete devices

within the boot, or is an integral part of the structure of the boot. This gets

compressed while you walk and generates a substantial voltage, which when

combined with appropriate electronics, can be used to charge a mobile phone

battery.

The other one involves placing small electro-mechanical

devices, such as a dynamo, in the heel of the shoe. The dynamo spins every time

your heel strikes the ground, thereby generating a small amount of current.

The piezoelectric device generates about 150 milliwatts of

power as of now, which is not sufficient to run a cellphone, but would be enough

to charge the battery slowly. The dynamo technology has the potential of

generating much more power than this, but the design would be more complex, and

hence more costly.

The boots were tested by Trevor Baylis–the inventor of a

radio that ran on windup technology–and a companion, in a trek across the

Namib desert. The trek was in support of a British anti-land mine charity. A

pouch was built on the outside of the boots, which held the PCB with the

electronics and connector for a cellphone battery and wired this directly to the

device in the heel that generated electricity. By the end of the walk, Baylis,

who wore the piezoelectric boots, was able to generate enough power to place an

international call to Richard Branson–the head of the Virgin empire–in

London.

The future outlook is for the boots to generate about 1-3 W

of power, so that they can power future microelectronic devices, like MP3

players, Global Positioning Systems, etc. More technologies will be tested for

this, and the issues of how much power can be generated, and how it can be

stored and distributed, will be addressed.

More information is available at the Website of The Electric

Shoe Company–www.theelectric shoeco.com–which is exploring the commercial

possibilities of the technology.

So, here’s to a future where you can listen to music on

your morning walk, or catch up with calls on your cellphone, without worrying

about dying batteries.