Design and implementation of a jellyfish otolith-inspired MEMS vector hydrophone for low-frequency detection

Abstract

Detecting low-frequency underwater acoustic signals can be a challenge for marine applications. Inspired by the notably strong response of the auditory organs of pectis jellyfish to ultralow frequencies, a kind of otolith-inspired vector hydrophone (OVH) is developed, enabled by hollow buoyant spheres atop cilia. Full parametric analysis is performed to optimize the cilium structure in order to balance the resonance frequency and sensitivity. After the structural parameters of the OVH are determined, the stress distributions of various vector hydrophones are simulated and analyzed. The shock resistance of the OVH is also investigated. Finally, the OVH is fabricated and calibrated. The receiving sensitivity of the OVH is measured to be as high as −202.1 dB@100 Hz (0 dB@1 V/μPa), and the average equivalent pressure sensitivity over the frequency range of interest of the OVH reaches −173.8 dB when the frequency ranges from 20 to 200 Hz. The 3 dB polar width of the directivity pattern for the OVH is measured as 87°. Moreover, the OVH is demonstrated to operate under 10 MPa hydrostatic pressure. These results show that the OVH is promising in low-frequency underwater acoustic detection.

Soft robotic shell with active thermal display

“…The cover design concept will also be extended to eventually embed other sensing modalities. It can be substantially enhanced with the promising developments in stretchable electronics 67 , 68 : one can easily imagine the possibility offered by on-line change of color or on-line change of texture patterns, together with enhanced tactile sensing modalities. We are also working to supplement our cover with a third inner layer that acts to modulate the robot shell stiffness on-line while having high impact absorption capabilities to increase safety.…”

MEMS Underwater Directional Acoustic Sensor in Near Neutral Buoyancy Configuration

“…Sensing the motion of the medium has been studied for decades by various research groups [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Leslie et al [ 1 ] described the operation of hydrophones enclosed within a spherical housing.…”

Batch Transfer Printing of Small-Size Silicon Nano-Films with Flat Stamp

“…Without the need for secondary alignment lithography and transfer print rate and pressure, flat stamp successfully transfers printed a 340 thick and 20 to 100 small rectangular pattern. The width of the pressure-sensitive unit of the existing rigid silicon-based hydrophone is 20 , which meets the size requirements of the pressure-sensitive unit of the hydrophone [ 19 ]. Furthermore, the progress has laid a foundation for combining silicon nano-films and PDMS materials in the MEMS field.…”