Push-To-Charge Cell Phones
Piezoelectricity is a property of certain materials to produce a voltage when mechanical pressure is applied on it. Thus when we press such materials, it produces a voltage and hence a current can flow. A push-to-charge cell phone is one of the latest applications of piezoelectricity. Whenever you press a button, it presses against a piezoelectric material which in turn produces a voltage that can be fed back into the battery of the phone. In this way we actually charge the phone while typing out a sms rather than draining its battery. This is an inexpensive method that helps to cut down electric energy if applied on a large scale.