The Research And Design Of Intelligent Turbidity Sensor

Water is the source of life, and it is necessary to measure the quality of water. Turbidity is an important index of water measurement, and the measurement of water turbidity is mandatory and more and more strict. The detection of turbidity has been attracted more and more attention. At present, foreign turbidity meters are dominated used in China, but their prices are expensive. Domestic turbidity meters are reasonable in price, but their reliability and stability (especially online turbidity meters) still have a very large upside potential. There are many kinds of domestic turbidity meters, but the few has outstanding quality. In order to improve the detection accuracy of turbidity sensor, this dissertation uses LS-SVM to fuse the following data to improve the measurement precision and anti-interference ability by analyzing the turbidity detection accuracy:the test data detected by scattering method, transmission method and ratio method, the temperature data and the ambient light data.The main work of this dissertation is as follows:1. The overall design of this system is presented, including hardware design, optical design and embedded software design. The hardware design mainly includes the circuit design of light source and detector, the structure of conditioning circuit, the data acquisition based on STM32. The turbidity structure is designed to ensure the reasonable layout of optical path, which mainly includes the choices and arranges of light source and detector so that it can meet the requirements of the international standard. The embedded software design mainly includes the initialization procedures and the basic hardware driving program so as to realize the function of data acquisition and data transmission.2. Turbidity algorithm model is established. The interference factors of turbidity senor are discussed, and LS-SVM is introduced to model the turbidity sensor. As a result, the detection accuracy by integrating the detected data of three methods is improved. In addition, light and temperature factors are joined in the model to improve the anti-interference capability.3. Design and carry out the evaluation experiment of turbidity sensor’s performance. The experiment results prove that the low turbidity range detection accuracy and anti-interference ability of turbidity sensor which is designed in this dissertation have been improved.