Design Of Transcranial Microcurrent Stimulation System Based On Vagus Nerve

With the acceleration of the pace of life and the acceleration of aging in China,the incidence of mental illness is increasing year by year.More and more people are suffering from psychiatric disorders such as epilepsy,schizophrenia,depression,anxiety,etc.These diseases have brought great distress to the lives of patients and seriously affected the quality of life of patients.The vagus nerve is the tenth pair of cranial nerves that are distributed directly from the head to the abdomen.The vagus nerve is responsible for innervating the muscles of the throat,soft palate,and part of the outer ear.The vagus nerve is also responsible for regulating sleep,mood,and the secretion of hormones in the brain.Studies have shown that stimulation of the vagus nerve can effectively alleviate and treat psychiatric disorders.A transcranial microcurrent stimulator for the vagus nerve is an instrument that applies specific direct current stimulation to brain nerves through electrode plates.Through electrodes clipped to the earlobe,the vagus nerve of the brain is stimulated by current stimulation of different frequencies and different currents.The vagus nerve of the brain is regulated by a variety of stimulus signals,thereby increasing the activity of the vagus nerve in the brain.Eventually,the effect of treating mental illnesses is achieved and the condition of patients is improved.The biggest difference between the transcranial microcurrent stimulator for the vagus nerve and the ordinary microcurrent stimulator is that the output signal accuracy is higher and the product filter performance is very demanding.This product will comprehensively optimize the filtering performance on software and hardware,and achieve the design goal through the combination of soft and hard methods.Another advantage of this product is the use of a variety of stimulation modes,a total of 6stimulation modes in the positive and negative directions,each stimulation mode,the parameters can be adjusted.Provide users with more treatment options.The transcranial microcurrent stimulator for the vagus nerve designed in this paper is a microcurrent stimulator with multiple stimulation modes and adjustable stimulation parameters.The hardware module is composed of a series of hardware modules such as MCU main controller module,power module,Bluetooth communication module,signal and waveform processing module,optocoupler isolation and drive withstand voltage module,and is integrated and controlled by STM32 chip.The STM32 chip performs 12-bit digital-to-analog conversion to precisely control the output current.In the design of hardware circuits,the filtering,buffering and isolation functions of the circuit are emphasized to improve the accuracy of the output signal.In terms of software and algorithms,the system uses the C language to write each software module.The control of the hardware module by the software algorithm is realized through the corresponding program,so as to realize the combination of software and hardware.And in the software module,through the human-computer interaction interface,the stimulation parameters are fed back,such as stimulation frequency,stimulation current size,stimulation time and other information.Among them,the algorithm focuses on the optimization of the filter function,and the improved variable step LMS adaptive filtering algorithm is used for optimization,thereby improving the accuracy and accuracy of the output signal.In order to verify the accuracy and reliability of the system design,the system was tested.Package and test prototypes,and debug hardware and software functions.The original algorithm and the improved algorithm are applied to the filter output test to verify the feasibility of the improved algorithm scheme.After that,the output signals of each forward and reverse waveform are data collected,and the relative error is obtained to verify whether the design goal is achieved.Finally,through the comparative experiment,the brain topographic map is drawn to verify the product and the effect.Compared with ordinary microcurrent stimacculators,the biggest advantage of the vagus nerve designed in this paper is that it uses a combination of software and hardware for filtering,which improves the stimulation accuracy.And more stimulation modes have been added,enriching the patient’s choice.