Electromagnetic based acoustic energy harvester for low power wireless autonomous sensor applications

Purpose The purpose of this paper is to develop a novel electromagnetic-based acoustic energy harvester (EH) for the application of wireless autonomous sensors. Design/methodology/approach The developed acoustic EH comprises a Helmholtz resonator (HR), a suspension system that consists of a flexible membrane and a permanent magnet, a couple of coils and a coil holder. Furthermore, the HR, used in the harvester, is designed for a specific resonant frequency based on simulation carried out in COMSOL Multiphysics®. Findings The developed harvester is tested both in lab under harmonic sound pressure levels (SPLs) and in real environment under random SPLs. In lab, when exposed to 100 dB SPL, the harvester generated a peak power of 212 µW. Furthermore, in real environment in vicinity of electric generator, the harvester produced an output voltage of about 110 mV collectively from its both coils. Originality/value In this paper, a novel geometric configuration for electromagnetic-based acoustic EH is proposed. In the developed harvester, two coils are placed in it to achieve enhanced electrical output from it for the first time.