Design And Implementation Of ECG Acquisition System Based On Flexible Electrodes

The fast-paced life often makes the contemporary people’s life pressure increase,forms the bad habit to cause the cardio-cerebrovascular disease.Heart disease has a high level of concealment,sudden and strong characteristics,and in the early stage of onset,heart rate is often obvious signs of abnormalities.According to medical research,body temperature is linearly correlated with heart rate,and the change of body temperature has a direct effect on heart rate.For the prevention of cardiovascular disease,people can take effective measures is the temperature and heart rate of dual monitoring,these physiological indicators directly reflect the health of the body,in clinical medicine is of great significance.In view of the above situation,the thesis designs and realizes the ECG acquisition system which is easy to wear,simple to operate and wireless data transmission.The system has the function of body temperature detection and heart rate monitoring.The system mainly consist of the flexible electrodes,temperature sensing module and ECG acquisition circuit.(1)Flexible electrodes:Through the analysis of the properties and properties of various flexible substrates,the electrical principle of the contact impedance of the skin and electrodes is studied in detail,the difference between the wet and dry electrodes in collecting the signals is expounded,and the size of the electrodes is designed according to the Nyquist sampling principle.Finally,a flexible electrode is fabricated on the PEN substrate based on the microelectro-mechanical system processing technology.(2)Temperature sensing Integrated circuit module:Based on the principle of CMOS integrated circuit design,through the LTspice software to simulate circuits,it is concluded that when the temperature range is-30 to 125℃,the temperature precision is 5.9mv/℃,and the use of Cadence Virtuoso on the Linux operating system draw temperature sensing IC layout.The layout can be encapsulated as a temperature sensor and can be ported to a chip for temperature sensing or other integrated circuits that require temperature perception.(3)ECG acquisition and processing circuit:Powered by 3V button battery,the signal is filtered,amplified and ad transformed by BMD101 ECG processing chip.SPP-CA as a Bluetooth module for wireless data transmission,through layout optimization and combined with human bionics,the Hardware circuit PCB board shape size optimization 45mm diameter circular circuit board.Through testing,the whole collection system can collect high quality ECG signals and verify the accuracy and feasibility of ECG acquisition system.This design is based on Tanner 1-edit design flexible electrode,using LTspice software for temperature sensor circuit simulation,based on the Linux operating system using Cadence Virtuoso software to draw temperature sensing IC layout.The schematic diagram and PCB design of ECG acquisition circuit based on Altium Designer software.The application of the system to the collection of ECG on the surface of the body can directly display the ECG waveform and verify the accuracy and practicability of the whole system.