by Emil Morhardt
In the Internet-of-Things, distributed sensors that collect data and transmit it to each other (and ultimately to a computer somewhere) wirelessly will become commonplace. They need a power source, but don’t want wires, or batteries that can wear out. Small photovoltaic panels work in some instances, but not always. Hence wouldn’t it be nice if a very small wind turbine came along. Yang et al., writing this week in Applied Physics Letters, invented an interesting one. It consists of a wind powered rotating drum, 3 cm in diameter, with several elastic balls inside that get dumped onto piezoelectric cantilevers as the drum rotates: the energy of the wind gets transferred to potential energy in the form of lifted balls, which then transfer their energy to the piezoelectrics when they fall on them. The piezoelectrics convert the kinetic energy of the balls into electricity, which can then be stored in a small supercapacitor for use as needed. No wires, no batteries, and not much mechanical that can wear out. Plus, the parts are cheap and readily available. And cleverly, the ends of the piezoelectric levers sticking out around the edge of the drum make perfect wind catchers.
Yang, Y., Shen, Q., Jin, J., Wang, Y., Qian, W., Yuan, D., 2014. Rotational piezoelectric wind energy harvesting using impact-induced resonance. Applied Physics Letters 105, 053901. Photo from the paper. Link to the abstract: http://bit.ly/V9aYEC