Researchers are trying to crack open an extremely common source of electricity – vibrations.

Engineers in Singapore are tapping into low frequency vibrations with a new energy harvester that can continuously convert vibrations across a wide frequency range into electricity.

Using the same basic idea that powers an electric guitar pick-up, ‘piezoelectricity’ may allow access to an extremely useful new power supply.

While the supply is fairly faint, the fact that the source is so common means devices could be charged almost constantly.

The new system has been designed by a team at A*STAR's Institute of Microelectronics (IME). It uses an aluminium nitride (AlN) based energy harvester with power density of 1.5 x 10-3 W/cm3. As a near-constant power supply, the remarkable power density feature translates into massive savings as costs and logistics associated with power source servicing become less relevant.

The vibration harvester can convert signals in a range from a 10th to 100 Hz. The wide sampling range makes it possible to more usefully harness real-world vibrational sources, despite of their irregularity.

“Our design strategy exploits the coupling effect between the Vortex shedding and Helmholtz resonating in order to enhance the Helmholtz resonating and lower the threshold input pressure,” said Dr Alex Gu, Technical Director of IME's Sensors and Actuators Microsystems Programme.

“By transferring the low frequency input vibrational energy into a pressurised fluid, the fluid synchronizes the random input vibrations into pre-defined resonance frequencies, thus enabling the full utilization of vibrations from the complete low frequency spectrum,” he said.

Professor Dim-Lee Kwong, Executive Director of IME, says; “This breakthrough presents tremendous opportunities to realise a practical, sustainable and efficient energy renewal model with attractive small-form factor, low cost solution for a wide range of applications from implantable medical devices, wireless communication and sensor networks, to other mobile electronics that enable future mobile society.”