Research Of Turbidity Measurment System Based On The LED

Water is an important material foundation for the survival of humans, and the qualityof water is directly relatted to the quality of human life. Turbidity is one of the importantparameters of measuring water quality,also one of the indispensable elements in waterquality monitoring.Therefore,in water quality monitoring indexes, turbidity as acomprehensive index is popular with the attention of water quality monitoring department.Turbidity measurement of water is the use of characteristics of light,according to thetransmission of light degree to determine the degree of turbid water. The transmission oflight degree is greater, the level of transmission turbidity is lower. The transmission of lightdegree is smaller, the extent of transmission turbidity is higher.First of all,this paper introduce the development situation of domestic and foreignturbid measurement, and analyses the deficiency of domestic turbidity meter existing incomparison with the foreig turbidity meter,also introduce the concept of turbidity and themeasurement method. By comparing,we choose transmission method to measure turbidityof water,and make detailed introduction about transmission method to measure for thistopic.Secondly,we use870nm LED as light source.The peak wavelength is960nmphotodiode as the photoelectric conversion device. At the same time,we design the LEDdriver circuit which base on constant current source, IV transfer circuit and signalamplification circuit are also designed.In this topic we also design the better stability powersupply voltage for the operational amplifier and singlechip in hardware circuit.Thirdly, the part of data acquisition choose two kinds of plan to collect absorbance inmeasuring water. Respectively,one is based on the data acquisition card USB2813(productby Art Technology Company) the other acquisition scheme is based on integrated MCUC8051F060.we design two kinds of plan for hardware circuit and softwareprogramming.Both plan also come true A/D conversion for the analog signal and processdata for the result of experiment. According to the result of accuracy and stability. Wedetermine the data acquisition system based on integrated MCU C8051F060as the finalplan design.Finally, calibrating data for results to fit out a regression curve. At the same time, givethe inspection and evaluation to the regression curve. Do the error analysis at the last.