FABRICATION & EVALUATION OF DRY ELECTRODES IN A LONG-TERM WIRELESS HEART MONITORING SYSTEM

This study examined the feasibility of using dry Au electrodes in a long-term wireless ECG system for early detection of heart diseases. While conventional ECG measurements are taken using wet Ag/AgCl electrodes, the use of wet electrodes is limited to short-term monitoring due to signal drift over time and skin irritation. Dry electrodes can overcome these issues, but they can be more susceptible to noise. This project comprised of three parts: electrode fabrication, hardware interface, and software data processing/analysis. Flexible gold dry electrodes were fabricated on polydimethylsiloxane (PDMS). The hardware interface consisted of an amplifier, Arduino microcontroller, and Bluetooth interface to a computer. Software code was written in the Arduino platform and in MATLAB to allow for real-time data acquisition, display, and analysis. Measurements compared the performance of the flexible dry Au PDMS electrode against a commercial standard Ag/AgCl electrode. The ECG signal from the gold dry electrode mounted in an armband or a Tegaderm self-adhesive bandage both showed a PQRST waveform as expected from a typical ECG. The calculation of the variance and the FFT of the signal showed that the there was no statistically significant difference in the amount of noise between the dry Au electrodes and the Ag/AgCl electrodes in a machine-free environment similar to a patient’s home. Further optimization with filters can minimize the effects of motion artifacts. While dry electrodes may not replace conventional wet electrodes for short-term use, such improvements will help make dry electrodes more viable for a long-term wireless heart monitoring system.