Design of a Biologically Inspired Directional Acoustic Sensor

摘要

The development of a novel, biologically inspired acoustic sensor will be presented. The primary goal of this effort is to construct a miniature device that is capable of detecting the orientation of an incident sound source with an accuracy of 2 deg. The design approach follows from our investigation of the mechanics of directional hearing in the parasitoid fly, Ormia ochracea. This animal has been shown to be able to detect changes in the line of bearing as small as 2 deg A. Mason, M. Oshinsky, and R. Hoy, 'Hyperacute directional hearing in a micro-scale auditory system,' Nature 4/5/01. The tympanal structures of the ears of this animal suggest a novel approach to designing very small directionally sensitive microphones. Candidate microphone diaphragm designs are presented that are being fabricated using silicon microfabrication technology. Model results indicate that the design can achieve significant performance improvements over the conventional approach of making directional microphones. This includes a nearly 20 dB reduction in self-noise, and roughly a factor of 10 improvement in low frequency sensitivity.