Walking can potentially increase the energy of your wearable electrical devices as well as your own energy levels. Osaka Metropolitan University scientists made a significant advance toward self-charging wearable devices with their invention of a dynamic magnifier-enhanced piezoelectric vibration energy harvester that can amplify power generated from impulsive vibrations, such as from human walking, by about 90 times, while remaining as small as currently developed energy harvesters. The results were published in Applied Physics Letters.
People carry various electronic gadgets on them now, including cellphones, and wearable technology is predicted to become more commonplace in the near future. Energy harvesting, a technology that transforms energy like heat and light into electricity that may power small devices, is receiving more attention as a result of the increased demand for more effective recharging of these gadgets.
Given that it can convert kinetic energy from vibration into electricity and is unaffected by weather or environment, a type of energy harvesting known as vibration energy harvesting is seen to be extremely practical.
A research team led by Associate Professor Takeshi Yoshimura from the Graduate School of Engineering at Osaka Metropolitan University has developed a microelectromechanical system (MEMS) piezoelectric vibration energy harvester that is only approximately 2 cm in diameter with a U-shaped metal component called a dynamic magnifier.
The novel harvester allows for an improvement in power conversion from impulsive vibrations, which can be produced by human walking motion, of around 90 times when compared to conventional harvesters.
The group has been working on creating vibration energy harvesters that make use of the phenomena known as the piezoelectric effect, which occurs when certain kinds of materials generate an electric charge or voltage in response to applied pressure.
So far, they have succeeded in generating microwatt-level electricity from mechanical vibrations with a consistent frequency, such as those generated by motors and washing machines. However, when applied vibrations are impulsive and nonstationary, like those produced by human movement, the power output of these harvesters is significantly reduced.
The team created and included the U-shaped vibration amplification component under the harvester as a solution to this problem. The component allows for improvement in power generation without expanding the device size.
In order to power small wearable devices like smartphones and wireless headphones, the technology is projected to create electric power from non-steady vibrations, including walking motion.
Professor Yoshimura concluded, “Since electronic devices are expected to become more energy-efficient, we hope that this invention will contribute to the realization of self-charging wearable devices.”
