A Wearable Electrocardiogram Monitoring System Based On Flexible Garment

Incidence of cardiovascular disease increases year by year, it has become a main threat to public health. Due to the instantaneity and unpredictability of heart disease occurrences, real-time monitoring is particularly important to patients with heart disease in order to detect their conditions timely. Traditional wet electrode may cause allergic dermatitis, and the electrocardiogram (ECG) monitoring node is bulky and heavy-weighted, hindering people’s daily lives. Therefore, it is of great significance to design a wearable ECG monitoring system without affecting people’s daily life. Utilizing conductive textile, the system could collect ECG signals and achieve real-time monitoring after long-time wearing.Firstly, two kinds of conductive fabrics, silver immersion type and ink spray type, were tested and compared by conducting washing and stretching on them, and conductive textile of silver immersion type was chosen as the flexible material of the system. Electrical experiments have also verified that conductive textile of silver immersion was suitable for manufacture of electrodes and wires. After assessment of material experiment, the electrode was designed to be circle and its diameter was 40mm with thickness of 5mm. To enhance the skin contact with cloth, a column of sponge with thickness of 5mm was placed on the cloth as a substrate and then packaged by another piece of conductive cloth. Meanwhile, experiments certified that crimp-type conductive fabric with length shorter than 25cm and width of lcm can be used in our system.Secondly, hardware and software of the single lead ECG node was designed according to the system scheme. Considering the application environment of wearable ECG node, flexible printed circuit was used to increase the flexibility of the system. It was confirmed that flexible ECG node can be used for ECG monitoring by comparing the ECG waveform acquired through flexible ECG node and electrocardiograph. The ECG waveform was produced by an ECG signal generator.After that, Android platform was chosen as the terminal of ECG monitoring system. This paper has completed monitoring software operating on smartphone, which achieved Bluetooth communication, ECG waveform display, ECG data storage and other functions. The smartphone monitoring program was tested to meet the requirements such as real-time ECG display and saving.Finally, the ECG monitoring system attached to garment was constructed by using fabric electrodes and fabric wires. Experiments were conducted to demonstrate the effectiveness of the system.Wearable ECG monitoring based on conductive textile was studied and designed in this paper. Experimental results indicated that the system can be used for ECG monitoring in daily life with some basic activities.