Mobile Device Particulate Matter Sensor Using Shaking Induced Air Flow
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Solution Overview
Problem
Existing particulate matter (PM) sensors for mobile devices are difficult to miniaturize and require frequent component replacements, such as filters in weight type sensors and quartz crystal microbalances in inertial mass type sensors, and often rely on large flow meters that consume power and reduce operational time.
Innovation Solution
A mobile device with a miniaturized particulate matter sensing structure incorporating a light-scattering type sensor, inertia sensor, and flow rate calculator, which uses air flow induced by shaking to measure particulate matter without a fan, allowing for real-time sensing and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow meter is used to supply air and measure flow rate in a light-scattering type sensor, then accurate particulate matter detection is achieved, but the device size becomes relatively large
Solution Approach 1:
The patent extracts and eliminates the flow meter component from the PM sensor system. Instead of using a traditional flow meter to supply and measure air flow, the invention uses the mobile device's shaking motion to naturally induce air flow through the sensor chamber, thereby removing the bulky flow meter while maintaining the light-scattering detection function
Solution Approach 2:
The system uses the mobile device's own shaking motion (inertia sensor detectable) to generate the air flow needed for sensing. The shaking of the mobile device itself serves to supply air through the air flow path, eliminating the need for external flow generation components
2Measurement precision
If weight type sensor components are used to collect PM, then accurate sensing is achieved, but the filter needs to be periodically replaced and real-time sensing is difficult
Solution Approach 1:
The patent replaces the mechanical filtration and weighing system with an optical detection system. Instead of collecting PM on a filter and measuring weight changes, the system uses light scattering to detect PM particles in real-time as air flows through the sensing chamber, eliminating the need for filter replacement and enabling continuous real-time monitoring
Solution Approach 2:
The system uses periodic shaking of the mobile device to induce air flow through the sensing chamber. This periodic motion creates continuous air circulation that allows real-time detection without the need for collection periods required by weight type sensors
3Measurement precision
If inertial mass type sensor components are used to measure PM weight, then sensing is achieved, but the quartz crystal microbalance needs to be periodically replaced
Solution Approach 1:
The patent replaces the quartz crystal microbalance (QCM) inertial mass system with a light-scattering optical system. Instead of measuring PM weight by mass accumulation on the QCM, the system detects PM concentration by measuring light scattered by particles in the air flow, eliminating the need for periodic QCM replacement
Solution Approach 2:
The system employs periodic shaking to create continuous air flow through the sensing chamber, enabling real-time detection of PM particles. This periodic action allows the system to continuously measure PM concentration without the accumulation and replacement cycles required by inertial mass type sensors
4Speed
If a fan is used to supply air in a light-scattering type sensor, then air flow is achieved, but power consumption increases and operational time is reduced
Solution Approach 1:
The system uses the mobile device's own shaking motion to generate air flow through the sensing chamber. The inertia sensor detects the shaking motion, and this same mechanical motion naturally drives air through the air flow path, eliminating the need for an external power-consuming fan
Solution Approach 2:
The patent extracts and removes the fan component from the PM sensor system. By using the mobile device's shaking to induce air flow, the system eliminates the power-consuming fan while maintaining adequate air flow for light-scattering detection
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 accurate, real-time particulate matter sensing with reduced power consumption and no need for frequent component replacements, while maintaining a compact design.
Implementation Method 1
A light-scattering type sensor emits light on a sensing region where air passes through and collects light scattered by PM
Implementation Method 2
an inertia sensor configured to detect an acceleration of the mobile device
Data Source
AI summary
A mobile device which senses particulate matter is provided. The mobile device includes a housing having an air flow path through which air flows when the mobile device is shaken; an inertia sensor that detects acceleration of the mobile device; a light-scattering type sensor that irradiates the air flow path with light and detects particulate matter in air flowing through the air flow path; and a controller that includes a counter for counting the particulate matter detected by the light-scattering type sensor, and a flow rate calculator for detecting an air flow rate of the air flow path based on a detection signal of the inertia sensor.