Charge your iPod while you trek the countryside, page 1

This is a pretty cool technology:

Backpack straps harvest energy to power electronics

All that rubbing of your backpack straps on your shoulders may be put to good use, now that researchers have designed a novel type of energy harvesting backpack. The pack 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.

The piezoelectric backpack straps are the latest innovation in the area of “energy harvesting,” where otherwise-wasted, ambient energy is converted into electrical energy to prolong the life of electronics. Mechanical engineers Jonathan Granstrom and Joel Feenstra from Michigan Technological University, Henry Sodano from Arizona State University, and Kevin Farinholt from NanoSonic, Inc., have published their results in a recent issue of Smart Materials and Structures.

The group’s intentions in designing the energy harvesting backpack were to make a device that was transparent to the user by not interfering with the user’s flexibility or endurance, as well as providing enough energy to reduce the need for carrying heavy batteries to power portable electronics.

The article continues by explaining how if the straps were to be applied to a typical soldier's backpack, it could generate 45.6 mW of power, all by simply walking.

Neat!