Microphone Array Airflow Characterization Without Moving Parts

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Solution Overview

Problem

Existing airflow measurement technologies, such as mechanical, ultrasonic, and thermal anemometers, face issues with scalability, high cost, maintenance requirements, and integration challenges, particularly in small devices like smartphones and cameras, while laser anemometers are too expensive and complex.

Innovation Solution

A method and apparatus using a microphone array to analyze acoustic signals generated by airflow turbulence, extracting characteristic information to determine airflow speed and direction through models like the Corcos model or machine learning techniques, without moving parts, allowing integration into devices with small form factors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional mechanical anemometers are used to measure airflow speed and direction, then measurement functionality is achieved, but device size, cost, and maintenance requirements increase

Engineering Contradiction:
Improveairflow measurement accuracyVSAvoiddevice structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical anemometer components with acoustic sensors (microphones) that detect airflow-induced sound waves. The microphone array captures acoustic signals generated by turbulent airflow, which are then processed to determine wind speed and direction, eliminating moving parts and mechanical complexity while maintaining measurement capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces acoustic signals as an intermediary between the airflow and the measurement system. Instead of directly measuring airflow with mechanical sensors, the system uses microphones to detect sound waves generated by airflow turbulence, and signal processing algorithms to extract velocity and direction information from these acoustic intermediaries

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If mechanical anemometers with moving parts are used, then airflow measurement is achieved, but response time increases due to inertial latency

Engineering Contradiction:
Improveairflow measurement accuracyVSAvoidresponse speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent eliminates mechanical moving parts by using microphones to detect airflow-induced acoustic signals. This substitution removes inertial latency entirely, as microphones respond instantaneously to sound pressure changes, enabling real-time measurement of rapid airflow variations and gusts without the 5-second minimum response time of mechanical systems

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If ultrasonic anemometers are used for accurate instantaneous measurement, then measurement precision improves, but device cost increases significantly

Engineering Contradiction:
Improveairflow measurement accuracyVSAvoiddevice cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses inexpensive microphones instead of costly ultrasonic transducers to detect airflow. Multiple low-cost microphones form an array that processes acoustic signals to achieve measurement accuracy comparable to expensive ultrasonic systems, dramatically reducing device cost while maintaining functionality

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates an acoustic copy of the airflow information by capturing sound waves generated by turbulent flow. This acoustic representation contains velocity and direction data that can be extracted through signal processing, providing an alternative to direct ultrasonic measurement at lower cost

Inventive Principle:
Principle #26Copying

4Measurement precision

If laser-based anemometers are used for precise measurement, then measurement accuracy improves, but device complexity and cost increase

Engineering Contradiction:
Improveairflow measurement accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex laser-based optical systems with simple acoustic sensing using microphones. The microphone array detects airflow-induced sound waves and uses signal processing to extract velocity and direction, achieving measurement accuracy without the complexity of laser optics, beam alignment, and specialized detectors

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Provides a cost-effective, accurate, and scalable solution for airflow characterization, capable of instantaneous measurements and integration into devices like smartphones and cameras, overcoming the limitations of traditional anemometers.

Implementation Method 1

acoustic signals generated by the airflow

Methodology Applied
Scientific EffectAcoustic signal generation by turbulent airflow: Turbulence

Implementation Method 2

acoustic signals generated by turbulent airflows in the proximity of the microphone

Methodology Applied
Scientific EffectSound wave propagation: Sound

Data Source

PatentEP3963340B1A method and an apparatus for characterizing an airflow
Publication Date: 2025.11.05 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3963340B1 patent drawingFigure 1a~1b
  • EP3963340B1 patent drawingFigure 2
  • EP3963340B1 patent drawingFigure 3a

AI summary

Method for charactering an airflow, comprising the following steps: receiving acoustic signals generated by the airflow by means of a microphone array; extracting a characteristic information from the acoustic signals; determining an information on the airflow based on the characteristic information.