Also, if you apply a charge it will deform shape in the same way. As MP3 players, cell phones, and other mobile electronics get more popular so will the demand for better charging and battery life. Another idea is using piezoelectric materials to capture sound waves due to the vibration they would cause in the material. This vibration could come from a busy street, a concert, or anything really.

In simple terms a piezoelectric material is one that can be mechanically deformed and will generate an electrical charge. One day you might be able to turn. These kinds of generators require no additional work on the part of the user and simply capture existing waste energy for reuse. Discovered over a hundred years ago piezoelectricity is only just starting to reach its full potential. The solution could be shoes with a piezoelectric sole that charge these devices as you walk. This has been used in a variety of ways in both old and modern electronics but only recently has it been discussed as a possible energy source.

One possible use would be as personal electrical generators.