Design And Implementation Of A Wearable ECG Monitoring System

Every year,more than 17.3 million people died from cardiovascular disease around the world.No longer confined to developed country,cardiovascular disease has caused 80%of the death in low-income countries.As the main cause of death in the world,the heart disease occurs irregularly,usually in a sudden.The short time ECG detection in hospital may not be able to check the abnormal electrocardiogram(ECG).The dynamic ECG monitoring system(Holter)used in clinical can't analyze the ECG data in real-time,neither can it alarm the possibility of heart attack.The disposable ECG electrode of the holter may cause skin allergies.In order to solve the above problems,this paper proposed a wearable ECG wireless monitoring system.The system realizes the acquisition and amplification of ECG signal and displays the ECG waveform in real time.The chief research contents of this paper are as follows:1.The design requirements of Wearable ECG monitoring system are analyzed.The system consists of four parts,which are the costume,the ECG signal measuring terminal,the ZigBee network and the PC software.The function of each parts are defined,and the performance index of the terminal hardware and software are determined according to the industry standard.2.The materials of the costume are selected to meet the requirements of the long-term ECG signal acquisition process in motion state.Design the style of the costume,determine the position of the electrode and guide lines in order to catch the standard ECG signal.The silver plated fabric material is used to make fabric electrode,replacing the disposable Ag/AgCl electrode,reducing the possibility of skin allergy in continuous monitoring process.The contact impedance,noise and safety of the fabric electrode and the Ag/AgCl electrode were tested and compared,and the results were analyzed.3.Design the hardware module structure of the ECG acquisition terminal.The ECG signal acquisition circuit includes preamplifier,a second amplifier,a lead-switch circuit,driven-right-leg circuit and several filter circuits.The hardware filter circuit reduces the noise in the signal acquisition process.The PCB circuit board is made and tested in the final part of this paper.4.Design the software program of microcontroller to drive AD7691 achieving the acquisition of the ECG signal.The microcontroller controls the lead-switch circuit to acquire 3-lead ECG signal in turn.Configure the UART module to realize the serial communication between the microcontroller and ZigBee network.The digital filter is designed to eliminate the interference during the acquisition progress of the ECG signal.5.Realize the transmission of ECG data from the ECG acquisition terminal to the PC terminal by ZigBee network.Implement ECG monitoring in real-time.