There is increasing concern among many (and that includes me) about the potential harm to the environment caused by batteries. With feature-packed gadgets requiring an increasing amount of power, disposal and recycling of batteries promises to become a global headache. So it's always heartening to see companies innovate and bring out devices that are powered by the good ol' "human effort + mechanical wizardry" combo. After launching hand-crank radios, Sony has now turned it's attention to digital cameras. It recently unveiled a hand-powered digital camera equipped with a wheel that can be turned to generate enough power to take photos. Shaped like a pizza cutter, an effort of 15 seconds on the wheel will generate sufficient juice to take one photo. So apart from the tree hugger effect, you have the added advantage of never worrying about running out of batteries for this camera. However, there are two major downers. There is no LCD to preview the photos and the camera is still a prototype. Though Sony currently has no plans to launch this camera commercially, increasing interest may spur it to do so in the future.