Design and development of a low cost system for acquisition of ECG, EOG, EMG, EEG

This research paper proposes a system that can acquire multiple biopotential signals. The main difference between Electromyography (EMG), Electroencephalogram (EEG), Electrocardiogram (ECG), and Electrooculography (EOG) signals lies in their frequency and amplitude ranges. The proposed system contains two parts i.e. analogue and digital. To make the proposed system general purpose, the analog part of the circuit is made common by introducing two low-pass filters. One of the two low-pass filters has to be selected to address high frequency range (below 500Hz) signals (EMG) or low frequency range (below 40Hz) signals (ECG, EOG and EEG). The digital filters are implemented in microcontroller for customized filtering of biopotential signal. Infinite impulse response (IIR) digital filters were designed for EOG, ECG, EMG and EEG. An embedded system with this hybrid analogue-digital filtering made the proposed solution a general purpose biopotentials acquisition system. This proposed system has potential biomedical applications for multiple biopotential measurements.