Vibrations to power small-scale electronic devices

Researchers from A*STAR’s Institute of Microelectronics (IME) are tapping into low frequency vibrations, the most abundant and ubiquitous energy source in the surroundings, to power small-scale electronic devices indefinitely.

IME’s energy harvester has the ability to continuously convert the vibrations - across a wide frequency range in different environments - into electricity. IME researchers have demonstrated an aluminium nitride (AlN)-based energy harvester with record-high power density of 1.5 x 10^-3 W/cm³ capable of generating electricity equivalent to three commercial implantable batteries over a 10-year period. As an inexorable power supply, the power density feature translates into massive savings as costs and logistics associated with power source servicing will no longer be relevant.

The energy harvester also extends the flexibility of low frequency vibrational sources that can be harvested by offering the widest sampling range from a 10th to 100 Hz. The wide sampling range makes it now possible to more productively harness real-world vibrational sources in spite of their irregularity and randomness.

“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. By transferring the low frequency input vibrational energy into a pressurised fluid, the fluid synchronises the random input vibrations into predefined resonance frequencies, thus enabling the full utilisation of vibrations from the complete low frequency spectrum,” said Dr Alex Gu, technical director of IME’s Sensors and Actuators Microsystems Programme, who conceptualised the energy harvester design.

Professor Dim-Lee Kwong, Executive Director of IME, said, “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.”