Researchers at Texas A&M University are conducting research they hope one day will lead to being able to charge your cell phone using just your voice. Their research centers around piezoelectric materials that generate electricity when a mechanical stress is applied. Piezoelectric technology is currently used in devices such as fireplace lighters and watches. The Texas A&M team is aiming to take the concept down to the nano level and has discovered that barium titanate crystal achieve greater power efficiency when manufactured at 21 nanometers. At this size, the materials become much more sensitive to pressure waves that even the sound of your voice could be used to generate electricity to power devices such as MP3 players, cell phones and even laptops. Researchers caution that it could be decades before the technology advances to the point where it can be used in consumer devices.