Gas Sensor Partitioning with Helmholtz Resonance for Noise Reduction

Solution Overview

Problem

Existing gas sensors suffer from measurement errors due to electrical interference between the infrared transmitter and acoustic sensor, and noise interference from external sounds, leading to reduced sensitivity and inaccurate detection results.

Innovation Solution

The gas sensor is designed with a partition plate dividing the receiving cavity into two separate compartments, housing the infrared transmitter and acoustic sensor in different cavities, forming a Helmholtz resonant cavity with a matching intrinsic frequency, and incorporating a vent hole to minimize interference and enhance sound signal strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the infrared transmitter and acoustic sensor are located in the same cavity, then the device structure is simple, but electrical interference occurs leading to measurement errors

Engineering Contradiction:

Improvedevice structureVSAvoidmeasurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The receiving cavity is divided into a first receiving cavity for the acoustic sensor and a second receiving cavity for the infrared transmitter using a partition plate. This segmentation physically separates the two components to eliminate electrical interference while maintaining a relatively simple overall device structure.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If the infrared transmitter and acoustic sensor are separated into different cavities, then electrical interference is reduced, but the device structure becomes more complex

Engineering Contradiction:

Improvemeasurement accuracyVSAvoiddevice structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The receiving cavity is divided into a first receiving cavity for the acoustic sensor and a second receiving cavity for the infrared transmitter using a partition plate. This segmentation physically separates the two components to eliminate electrical interference while maintaining a relatively simple overall device structure.

Inventive Principle:

Principle #1Segmentation

3Productivity

If external sound signals are present, then the device can detect gas, but noise interference reduces detection accuracy

Engineering Contradiction:

Improvedetection capabilityVSAvoiddetection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The first receiving cavity, through hole, and second receiving cavity form a Helmholtz resonant cavity tuned to match the modulation frequency of the infrared transmitter. This resonance amplifies the acoustic signals generated by gas absorption at the specific frequency while filtering out external noise signals at different frequencies, thereby improving detection accuracy.

Inventive Principle:

Principle #18Mechanical vibration

4Quantity of substance

If the gas concentration is high, then the absorption signal is strong, but noise interference becomes more prominent

Engineering Contradiction:

Improvegas concentrationVSAvoidnoise interference

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The first receiving cavity, through hole, and second receiving cavity form a Helmholtz resonant cavity tuned to match the modulation frequency of the infrared transmitter. This resonance amplifies the acoustic signals generated by gas absorption at the specific frequency while filtering out external noise signals at different frequencies, thereby improving detection accuracy.

Inventive Principle:

Principle #18Mechanical vibration

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

This design significantly improves sensitivity by 10-20 dB, reducing noise interference and enhancing signal strength through acoustic resonance, resulting in more accurate gas concentration measurements.

Implementation Method 1

the first receiving cavity, the through hole, and the second receiving cavity form a Helmholtz resonant cavity, an intrinsic frequency of the Helmholtz resonant cavity is the same as a modulation frequency of the infrared transmitter

Methodology Applied

Scientific EffectHelmholtz resonance: Helmholtz Resonance

Implementation Method 2

the infrared transmitter emits infrared light of a specific wavelength at a certain sound frequency (e.g., 30 Hz). This wavelength of the infrared light is strongly absorbed by the gas to be measured and converted into heat

Methodology Applied

Scientific EffectInfrared absorption: Absorption (EM radiation)

Implementation Method 3

An alternating pressure signal is generated in the internal chamber, which is received by the acoustic sensor and converted into an electric signal

Methodology Applied

Scientific EffectPhotoacoustic effect: Photoacoustic Effect

Data Source

PatentUS12385824B2Gas sensor

Publication Date: 2025.08.12 AAC ACOUSTIC TECH (SHENZHEN) CO LTD

AI summary

The present disclosure provides a gas sensor, including a shell with a receiving cavity, an infrared transmitter, an acoustic sensor and a partition plate accommodated in the receiving cavity. The partition plate is connected with the substrate and the side wall, the partition plate divides the receiving cavity into a first receiving cavity and a second receiving cavity, the acoustic sensor is located in the first receiving cavity, the infrared transmitter is located in the second receiving cavity. Compared with the related art, the gas sensor disclosed by the present disclosure could improve the sensitivity of the product.