A Design Of Wearable And Insole Plantar Pressure Measurement System Based On The STM32

The parameter of plantar pressure is one of the important physiological parameters of the human body.It has great value of reference in the field of clinical medicine and rehabilitation. In this study, a plantar pressure measurement device is designed to detect the plantar pressure parameters of the human body, it consists of three parts: the plantar pressure sensor with shape of shoe pad, the control board of data acquisition and the pressure measurement software. The control board of data acquisition sequentially scans each sensing unit of the foot pressure sensor to obtain data,then transmit the sampling data to the pressure measurement software for drawing and data analysis, that is, the completion of a plantar pressure measurement.Plantar pressure sensors are divided into right and left foot pressure sensor. Each sensor includes up to 900 sensing units and 4 sensing units per square centimeter. Every pressure sensor has a total of three layers, in the middle layer, a conductive film with the function of piezoresistive is selected as the sensor,the upper and lower layers choose silver thin films as the row and column conductive layers.Each row and column of the upper and lower silver thin films is connected with a certain channel of the analog switchs, through the analog switchs to select a sensor unit, and then all sensing units can be measured by the array scanning.Stm32f103vet6 which based on Cortex-M3 kernel is chosen as the main control chip of the control board of data acquisition. The hardware circuit includes a power supply circuit, a multi-channel analog switch circuit, an adjustable constant current source circuit, a signal conditioning circuit, an analog to digital conversion circuit, a communication circuit, a human-computer interaction circuit,etc. In which the analog to digital conversion circuit using the internal 12 bits ADC of stm32f103vet6, the other circuit modules are composed of discrete chips and peripheral circuits.The sampling procedures of the control board based on the STM32 official firmware library and use RVMDK as the development tool.The pressure measurement software of the host computer is used to display the pressure image and analyze the sampled data in real time. The integrated development environment of this software is based on MyEclipse, using JAVA language to write the PC program and MYSQL as the backend database. The whole software includes five modules: user information module, pressure drawing module, data analysis module, history module and system setting module.At last, tests and validates the entire design, including the calibration of plantar pressure data and the test of each functional module of the software.