Weapons Response Group

The idea of capturing the energy surrounding an electronic system and converting it into usable electrical energy that could extend the lifetime of the power supply or provide an endless supply of energy has captivated many researchers and brought much attention to power harvesting. One method of obtaining the energy surrounding a system is to use piezoelectric materials. Piezoelectric materials have the unique ability to interchange electrical and mechanical energy. This property allows them to be uses to absorb the mechanical energy around a system, usually ambient vibration, and transform it into electrical energy that can be used to power other devices. However, the amount of energy generated by piezoelectric materials is far smaller than that needed by most electronic devices. Therefore, methods of accumulating and storing the energy generated until sufficient power is captured must be developed. This paper quantifies the amount of power generated by a piezoelectric plate and investigates two methods of accumulating the energy produced. The first uses a capacitor, which has been a common method of accumulating the energy produced and the second method is the use of nickel metal hydride batteries. The advantages of each method are discussed and the rechargeable battery is found to have more desirable qualities than the capacitor. It is shown that the power output of piezoelectric materials is compatible with that needed by a rechargeable battery and that a 40mAh battery can be charged in slightly under one hour.