THE NEXT BIG THING?

There is no shortage of interesting, green-friendly ways to charge your cellphone, starting with solar chargers. But there aren’t many peripherals that promise to take inches off your waistline while providing an easy and portable power source. Uncharted Play’s Pulse energy-harnessing jump rope works by transforming kinetic energy into usable electricity. A few minutes of skipping rope will generate a few hours of power that’s stored in the handles and is transferred with an adapter to run cellphones, lights, and other gadgets. The device isn’t exactly cheap, however: An initial, limited run of the Pulse will set would-be rope skippers back around $129 per unit. The company’s eventual hope, said Derek Markham at TreeHugger.com, is to reduce costs “so that they are more affordable for people in the developing world.”