Helmholtz Resonator Sound Direction Sensor
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Solution Overview
Problem
Existing acoustic wave direction sensing systems require significant spatial distance between microphones, making them unsuitable for compact designs and applications that benefit from smaller sizes.
Innovation Solution
A sound direction sensor comprising two Helmholtz resonators oriented in different directions, each with a microphone in its acoustic chamber, allowing for compact detection of acoustic wave incident angles by determining the power ratio of resonator responses, which can be extended to three-dimensional detection using orthogonally positioned devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase-difference acoustic direction sensing systems use multiple spaced-apart microphones, then measurement precision is improved, but device complexity and size increase significantly
Solution Approach 1:
The patent divides the acoustic sensing function into multiple independent Helmholtz resonators, each tuned to detect sound from a specific direction. By segmenting the directional sensing into discrete angular sectors rather than using continuous spatial arrays, the system achieves precise incident angle detection without requiring large inter-microphone distances or complex spatial arrangements.
2Measurement precision
If traditional microphone arrays are used for acoustic direction sensing, then measurement precision is improved, but the device size becomes too large for compact applications
Solution Approach 1:
The patent changes the operating parameters of the resonators, specifically tuning each Helmholtz resonator to a distinct resonant frequency that corresponds to sounds arriving from specific directions. This frequency-based parameter differentiation allows the system to encode directional information in the frequency domain rather than requiring large spatial separations, enabling compact sensor design while maintaining precise incident angle detection.
3Measurement precision
If multiple spaced-apart microphones are deployed, then incident angle detection capability is improved, but ease of operation and integration into compact devices deteriorates
Solution Approach 1:
The patent creates a universal acoustic sensing platform where multiple Helmholtz resonators with different directional sensitivities work together within a single integrated housing. Each resonator serves multiple functions: it acts as a directional filter, a frequency-selective amplifier, and an acoustic antenna. This multi-functionality allows the compact device to achieve sophisticated incident angle detection capabilities without requiring separate components or complex integration procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables compact and efficient detection of acoustic wave incident angles in two or three dimensions, facilitating smaller designs and improved adaptability to various applications without the need for extensive spatial arrangements of microphones.
Implementation Method 1
A sound direction sensor includes two Helmholtz resonators. Each of the first and second Helmholtz resonators has at least one exterior wall defining an acoustic chamber and a neck placing the acoustic chamber in fluid communication with an ambient environment.
Implementation Method 2
The present teachings provide devices for detecting the incident angle of acoustic (sound) waves. A disclosed device can be substantially smaller than the wavelength of the detected acoustic wave
Data Source
AI summary
Sound direction detection devices include cylinders or other longitudinally extended structures having rotational symmetry about their longitudinal axes and multiple, rotationally equivalent resonators contained therein. Each resonator contains a microphone or other transducer that is activated when the resonator resonates.