Acoustic resonators for detecting low frequency events

Acoustic resonators and related concepts have long been the subject of research for acoustic filtering in free space or energy harvesting applications. In this work, we instead apply acoustic resonators to low frequency (< 50 Hz) non-contact bio-signal sensing within a vehicle cabin. We describe our approach to the design of the resonator and method of simulation in this low frequency regime. Validation of select designs through experiments in both free space and using a coupled bodies method is discussed. We also demonstrate the bio-signal collection in situ and discuss challenges associated with a real-world, noisy, dynamic environment. Future work including signal processing of noisy data to recover the base bio-signal and ideas for miniaturization of the device are touched upon.