ECG and PPG Signals Monitoring by Using Web Audio API

This paper presents the methodology for real time capturing and processing Electrocardiography (ECG) and Photoplethysmography (PPG) signals by using the audio interface and Web Audio API in combination with JavaScript. The signals are translated in the frequency spectrum by AM and FM modulators and transmitted to the microphone by the cable or via the air. The capturing, filtering, demodulation, visualization and further manipulation of the signal is implemented in HTML+CSS+JavaScript software technology using Web Audio API and CanvasJS API. The obtained results have shown that such approach can be a simple, but effective alternative, for more complex systems of similar purposes. The method can be equivalently applied to other vital signals or to any slowly up to middle changing signal. As a target machines, the standard computers and gadgets are used. The hardware-software architecture, processing methodology as well as the results of preliminary testing are elaborated.