Dual Microphone Inhaler Flow Detection via Noise Suppression
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Solution Overview
Problem
Current inhalers, particularly Metered Dose Inhalers (MDIs), face challenges in ensuring patients inhale medication at the optimal flow rate due to complex operation requirements and high failure rates, with existing noise-based monitoring systems being unreliable in normal environments.
Innovation Solution
An inhaler system equipped with two microphones positioned on the external surface, spaced apart to capture sound and vibrations, processes signals to accurately measure inhalation flow rates within 15-120 liters per minute, suppressing background noise and identifying events like priming, firing, and inhalation, providing user feedback for proper technique.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single microphone is used to capture sound for determining inhalation flow velocity, then the device structure is simple, but the measurement reliability is poor in normal environments with background noise
Solution Approach 1:
The single microphone is divided into two separate microphones positioned at different locations on the inhaler housing. This segmentation allows the system to capture sound signals from multiple positions, enabling differentiation between background noise and actual inhalation sounds through spatial analysis, thereby improving measurement reliability without significantly increasing device complexity
Solution Approach 2:
The processor acts as an intermediary that receives signals from both microphones and applies signal processing algorithms to distinguish inhalation sounds from background noise. By using the spatial relationship between the two microphones as an intermediary mechanism, the system can filter out ambient noise and reliably determine flow velocity even in noisy environments
2Measurement precision
If multiple sensors are positioned at different locations on the housing, then the flow measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The two microphones are positioned at specific locations with different distances to the air-inlet, creating local quality differences in sound capture. The first microphone is positioned closer to the air-inlet while the second is positioned farther away, allowing the system to detect flow-induced sound variations at different local positions, thereby improving flow measurement precision through spatial differentiation
Solution Approach 2:
The system transitions from a single-point sound measurement to a spatial distribution of measurements by positioning microphones at different locations on the housing. This dimensional change from one dimension (single point) to two dimensions (spatial distribution) enables the system to extract flow information through spatial analysis, improving measurement precision while maintaining manageable device complexity
3Ease of operation
If the inhaler provides comprehensive feedback and event classification, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The processor analyzes sound signals from the two microphones to classify events (priming, firing, inhalation) and provides feedback to the user about their inhalation technique. This feedback mechanism guides users to perform correct inhalation maneuvers by comparing their actual performance against optimal patterns, thereby improving ease of operation through intelligent assistance
Solution Approach 2:
The inhaler system performs self-diagnosis and self-guidance by automatically analyzing its own operational sounds and providing real-time feedback without requiring external monitoring equipment. The device uses its built-in microphones and processor to autonomously classify events and guide user technique, reducing the need for complex external testing equipment while improving ease of operation
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
The system effectively measures inhalation flow rates and event timing, enabling users to learn optimal inhalation techniques and ensuring correct medication delivery, even in noisy environments, by using signal processing techniques to differentiate between inhalation and background noise.
Implementation Method 1
the first and second sensors are arranged to sense sound or vibrations resulting from a flow in the flow path
Implementation Method 2
a processor arranged to process output signals from the first and second sensors according to an algorithm, so as to generate a measure of flow in the flow path
Data Source
AI summary
An inhaler with a housing (H) comprising an air-inlet (A_I) and a an air-outlet (A_O). Inside the housing (H) a flow path (FP) is defined between air-inlet (A_I) and air-outlet (A_O) where a dispenser (DP) is arranged to dispense an aerosol or a dry powder in the flow path (FP). Two sensors (S1, S2), e.g. microphones, are positioned spaced apart at external surfaces of the housing (H) to sense sound or vibrations resulting from a flow in the flow path (FP) at two different positions. This allows a precise detection of flow velocity during inhalation based on the sound or vibrations sensed by the two sensors (S1, S2), thus allowing examination of correct use of the inhaler. Further, the use of two spaced apart sensors (S1, S2) facilitates identification of priming and firing events in the sensed sound or vibrations which may also be used in evaluating the use of the inhaler. Preferably, a noise reduction algorithm is used that exploits the differences in the captured sound or vibrations from the two sensors (S1, S2), so at to allow precise flow measurements even in noisy environments.