Design And Realization Of Milk Deterioration Degree Detection System Based On AC Impedance Analysis

With the improvement of quality of life,people pay more and more attention to cultivating a balanced diet.Milk contains a variety of nutrients that human body needs,which is essential nutritional supplement source for our daily life.Generally,we determine whether milk can be consumed only using the production date and shelf life offered by the manufacturer.However,in the process of transport and sale,milk packaging may be damaged,which will lead to deterioration of milk.So judging whether milk is deteriorated only according to the shelf life is not accurate.Therefore,it is necessary to develop a detection system for detecting the degree of milk deterioration.Comparing the existing methods of milk quality detection,we chooses the AC impedance analysis method which is expert in anti-interference to achieve the milk deterioration detection.The chemical composition change of milk led to a dielectric properties and a capacitance value change while milk is deteriorating,which result in resonant frequency offset of the equivalent LRC circuit,and we can detect the degree of milk deterioration by utilizing resonant frequency offset.Firstly,an equivalent circuit model of milk deterioration degree detection based on AC impedance analysis is proposed.Secondly,combined with the network analyzer and drum-type capacitor,we estabilsh the experimental platform,and complete the milk deterioration process testing.Finally,the milk deterioration detection system based on the network analysis technology was designed.Compared with other milk quality detection methods and instruments,our detection system developed in this paper does not require petri dishes and chemical reagents,and has the advantages of simple operation,high sensitivity,strong anti-interference ability and real-time rapid detection.Around the specific needs of the milk deterioration degree testing,this paper mainly studied the followings:(1)We proposed a equivalent circuit model of the testing system,analysed its theory and select the optimal parameters of the capacitor according to the actual situation.The drum-type capacitors was designed by the parameters and printed out through the 3D printer.(2)Based on the network analyzer and the drum-type capacitor,the milk deterioration degree detection platform was set up,and the real-time detection experiment of the milk deterioration was designed.The relationship between the resonant frequency offset and the degree of milk deterioration was analyzed according to the experimental data.(3)A household milk deterioration degree detection system based on FPGA + ARM architecture was designed for detecting the circuit's return loss coefficient.Detailed inspection system structure and working principle was discussed.System hardware circuit and its drive design was highlighted.(4)Software of the milk deterioration degree detection system was designed based on Qt5.(5)The embedded system and application software was ported to the Cortex A9 and running normally.(6)Through the experiment,the validity and feasibility of the whole system are verified.