Research And Development Of Laser Based Micro-Dust Density Detector

With the rapid development of industrialization and urbanization in China,the increasing resource consumption has accelerated the burden of urban atmospheric environment,making the problem of urban air pollution becomes prominent.Micro-dust is the chief pollution source which seriously endangers physical and mental health of human being.Nowadays,there are many kinds of instruments to detect the micro-dust density in the market,most of which are expensive in price and huge in shape.It is necessary to develop a set of portable micro-dust density detector.Based on a large number of references and comparative analysis,the key points of the research are determined.The main work in this paper is formed by four parts:Firstly,the principle and characteristic of methods by way of sampling and non-sampling is studied.The light scattering method of laser is applied to detect micro-dust density.According to the design indexes,the structure and circuit modules are proposed.The whole scheme of the detector is also proposed.Secondly,the structure of cavity for sensing micro-dust density is designed to make sure the detecting air floating in and out.The air chamber,inlet,outlet,reflector,diaphragm and optical trap are designed to miniaturize the detector.The laser lectotype and optical sensors selection are determined.Thirdly,the hardware of this instrument which include data acquisition circuit,controller and auxiliary circuit,are designed and developed.The controller is based on ARM processor.The data acquisition circuit includes amplifier and pulse comparison circuit.The auxiliary circuit includes the control circuit of power supply and fan.The data acquisition process method,signal filtering algorithm and micro-dust density detecting method are developed to promote the precision.Finally,other typical instrument is used to test the developed detector.The detecting data and analysis by PM1.0,PM2.5 and PM10 of developed detector in this paper and other typical instrument shows its feasibility and stability.