A novel battery charger operated from random sound sources or air pressure

Design and implementation of a novel cell phone charger using renewable energy is reported in this work. Conventional cell phone charger takes main line ac source as input, then rectify it and step it down to charge the battery. The cumulative power taken per day from the main line by all the mobile phone users over the world or in a single country is not a small amount. So, if there is alternative way of charging mobile batteries, a significant amount of power can be saved. Here, random sound energy or air pressure is proposed as a new source of renewable energy which can be easily used to charge a mobile phone battery through suitable energy conversion circuit. Piezoelectric material is used here as the transducer to convert sound energy or air pressure into electric energy. The produced electric energy is then processed through simple circuit to make suitable output which can directly charge any commonly used cell phone battery. The proposed set up is simple, portable and especially useful in rural areas where there is no electric power at all. It is also helpful during natural disaster when electric power may not be available in a particular area. The performance of the circuit for different frequencies of sound was tested. Some ways to improve the overall performance of this circuit were also prescribed.