Research And Development Of Key Technology For The Portable Body Composition Analyzer

In modern life,people have more and more attention on the specific content of body components and its changing trend,for one hand,to prevent epidemic diseases such as obesity,for the other hand they can guide people to a reasonable diet and exercise.Bioelectrical impedance analysis is now a very popular approach of noninvasive and nondestructive measurement of body composition.By infusing the invariable-value and variable-frequency alternating electric current into bodies and collecting the energizing voltage generated by bodies,researchers are able to calculate the bioelectrical impedance of a human body and to deduce different contents of corresponding compositions.Both the frequency of current and the measuring accuracy of impedance impact directly the performance of measuring various physical compositions.This thesis aimed at the existing body composition analyzer with embedded system.At present,there are two categories of products prevailing in the market:one adopts the four-electrode structure and single-frequency measurement,which leading to low measuring accuracy and single function;another adopts eight-electrode structure and multiple-frequency measurement,which leading to complete functions but complex structures and large size.The second kind of product can only be applied in hospitals and physical examination center and cannot spread in families.This thesis designed a portable body composition analyzer on the premise of guarantee accuracy of measurement.In order to ensure accuracy,this thesis designed the special human body impedance measurement circuit.In order to easy to carry,this thesis upgraded the hardware with embedded system and reduced the overall volume.According to the above work,a portable body composition analyzers based on the STM32 processor and the AFE4300 chip had been designed and executed,and corresponding software had also been developed.In this paper,the main work is as follows:1.The collecting circuit of body impedance had been constructed.The design of hardware and the size of system had been simplified.The aforementioned part laid the root for portable design of entire system.The operating circuit of AFE4300,the weight measuring circuit and signal preprocessing circuit had been developed.2.The STM32 processor was used to control the whole measuring process,the calculation of measuring results,the display of measuring results and the communication of measuring results.The keyboard and the liquid crystal display were used as graphical user interface,which can accomplish the whole measuring process independently.3.The software of the entire embedded system had been accomplished,which effectuates the weight measurement,impedance measurement,calculation of body compositions and communication of results.The PC software had been accomplished by using Labview.The PC software can extend functions of the entire system and application platform,which laid a favorable root for subsequently functional development and transplantation of platform.