Hybrid flexible circuit on cotton fabric for wearable electrocardiogram monitoring

Abstract

One of the ways to reduce the risk of fatality due to cardiovascular disease is by long-term monitoring of the heart condition. Recently, various designs of wearable and flexible ECG monitoring systems have been developed in order to allow long-term monitoring of the heart condition. One of the most important features of flexible ECG monitoring systems is the ECG circuits which perform the ECG signal processing. The circuit should be properly optimized and characterized so that it can meet the overall requirements of a monitoring system, and produce accurate results for further analysis. The purpose of this research is to develop a flexible circuit on cotton fabric to be used in ECG signal monitoring with diverse function and application. Cotton fabric is chosen to be the substrate material in the circuit fabrication due to its low cost, light weight and high flexibility. This research includes material processing, circuit fabrication and characterization, and prototype testing. Reduced graphene oxide (rGO) is used as the conductive materials of the circuit wiring because of its high electron mobility, high flexibility and biocompatibility which make it suitable to be implemented in flexible devices for long term monitoring. The rGO circuit was used to connect the electrodes with the Arduino processing board and the Bluetooth communication module. The Arduino board and bluetooth module were still implemented using conventional printed circuit board. The results of this hybrid flexible circuit demonstrated that the flexible cotton fabric-based circuit can produce clear ECG signals with high flexibility that enhances the user's comfort, which show a promising approach to produce a full cotton fabric-based ECG system for long term monitoring.