Wireless Portable Brain Signal Acquisition System Design And Experimental Verification Analysis

With depth research of electroencephalography(EEG)signal,the requirements for the performance and portability of EEG signal acquisition equipment are gradually increasing.In order to help more researchers to use portable EEG acquisition equipment,based on the design of traditional EEG acquisition equipment.we designed an 8-channel wireless portable low-cost EEG acquisition system which could be used with dry electrodes,In this study,an impedance detection circuit was designed with constant current source as the excitation source.The STM32C8T6 processor chip was used as the main signal acquisition device.In order to be portability,the device was powered by lithium battery,with overcharge and over discharge protection circuits were designed for the battery.In addition,EEG signals were transmitted by wireless Bluetooth.To verify the performance of the EEG acquisition system,a lot of tests have been performed based on the JJG1043-2008 standard.The testing parameters include system gain,common-mode rejection ratio,supplying voltage,time interval,noise,bandwidth and power consumption of the system.All the testing results meet the standard requirements.Meanwhile,we tested the current of the constant current source and the error of impedance detection part.The average error of the 8-channel impedance detection was 1.14%.The effective reception distance of bluetooth transmission distance was 5 meters.According to the electrical safety standard GB9706.1-2007,the EEG acquisition equipment proposed in this study was qualified and obtained an inspection report relevant agencies test.In present study,a confirmatory experiment was designed to further verify the performance of the EEG signal acquisition equipment,a confirmatory experiment was designed in this study.Using open-eye,close-eye,Steady-State Visual Evoked Potentials(SSVEP)and Event-related Potential(ERP)P300 experiments,we compared selfdesigned EEG acquisition equipment with domestic equipment sold by Xintuo and the AMP DC equipment of German Brain Products(BP).This study used the noise rootmean-square value to measure the impact of adding an adapter interface to the device.A total of 12 subjects’ EEG data was collected for comparison experiments.one-way analysis of variance and paired t-test analysis were performed to investigate the differences between equipment.The results showed no significant differences between the self-designed equipment with dry electrodes and the matched wet electrodes,which suggested that dry electrode could be used to replace the wet electrode.In the case of using wet electrode,there is no different performance between the self-designed equipment and Xintuo and BP in above experiment,which demonstrated that the selfdesigned equipment with wet electrode can reach the same effect of experiment of Xintuo and BP equipment.