A bio-inspired optical directional microphone with cavity-coupled diaphragms

Area of Science:

• Acoustic sensing
• Bio-inspired engineering
• Signal processing

Background:

• Sound source localization is crucial for many applications.
• Existing acoustic sensors often lack the directional sensitivity of biological systems.
• Vertebrates and insects utilize internally coupled ears for effective sound localization.

Purpose of the Study:

• To develop a bio-inspired acoustic sensor for enhanced sound source localization.
• To mimic the internally coupled ear structure found in nature.
• To investigate the amplification of interaural phase difference using a novel sensor design.

Main Methods:

• Fabrication of a large-scale prototype acoustic sensor with two coupled aluminum diaphragms.
• Utilizing a U-shaped cavity to couple the diaphragms.
• Detection of diaphragm displacement using a low-coherence fiber optic interferometer system.
• Experimental validation and comparison with simulation results.

Main Results:

• The bio-inspired sensor successfully amplified the interaural phase difference by a factor of 2 to 4.
• This amplification was observed across a wide frequency range (0.5-2 kHz).
• Experimental results showed good agreement with simulation predictions.

Conclusions:

• The developed cavity-coupled diaphragm mechanism is effective for acoustic sensing.
• This bio-inspired approach offers a promising pathway for advanced sound source localization sensors.
• The sensor design demonstrates potential for improved directional audio perception.