I am planning to do a small project based on piezoelectric effect. The idea is to sandwich a piezoelectric crystal in-between metal plates and use it as a school bell or a small calling bell. I am planning to use a battery (need not be full, which holds charge enough to ring the bell for the first time). The battery rings the bell and vibrations are produced. The vibrations would be converted to electrical energy which is utilized for re-charging the battery. And by doing so a bell which does not depend on the consumer electricity is produced. The main idea is to make it work during power cuts. I am planning to implement the circuit http://ej.iop.org/images/0957-0233/23/1/015101/Full/mst399991fig10.jpg The battery in-turn is connected to the PZT crystal. Using switch, charging and discharging operation can be established. Will this idea workout? Are there any flaws?