As soldiers, hikers and students can testify, it takes energy to haul around a heavy backpack. Now, researchers have developed a backpack that turns that energy into electricity.
It doesn’t crank out a lot of juice — just a bit more than 7 watts — but that’s enough to run things like an MP3 player, a personal data assistant, night vision goggles, a handheld global positioning system or a GSM cell phone.
The development could eventually allow field scientists, hikers, explorers, soldiers and disaster workers to produce their own electricity.
The researchers used a backpack fastened to the carrying frame by springs. The up-and-down motion caused by walking powers a small generator, producing electricity that can be used directly or stored in a capacitor or battery.
The electricity-generating frame weighs about 10 pounds, researcher Lawrence C. Rome, of the University of Pennsylvania, said in a telephone interview. He’s working to lighten it, so it will weigh only a couple of pounds more than a standard backpack. Power generated increases as the load in the backpack gets heavier, he said. Tests ranged from loads of about 40 pounds to about 80 pounds.
