Development of a AD8233-Based EMG Sensor and Double Interrupt Sampling Technique in a Low-Cost Prototype for Biosignal Acquisition

According to the World Health Organization, mental disorders have important repercussions in people's health, monitoring physiological parameters on patients becomes useful to identify mental disorders, but these devices are often expensive, which limits their availability to educational and research institutions. In this work, a low-cost equipment for the acquisition of biosignals such as body temperature (BT), electrocardiograph (ECG), electromyogram (EMG), galvanic skin resistance (GSR), heart rate (HR), oxygen saturation level <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$( {\text{Sp}{\mathrm{O}_2}} )$</tex> and a sensor based on the AD8233 integrated circuit for the acquisition of EMG was developed applying the Nyquist theorem. Furthermore, a new sampling method is employed in which two software interrupts at different frequencies are used with the ATmega2560 microcontroller allowing the sample of multiple signals at the same time. This work demonstrated that the development of an electromyogram sensor based on the AD8233 integrated circuit provides a full electromyogram signal. Furthermore, the developed prototype with an Arduino Me ga board can acquire 6 biosignals simultaneously using two sampling frequencies on test over 6 hours, operating at a fixed 1 Hz for BT, GSR, HR and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Sp}{\mathrm{O}_2}$</tex> while at the same time ECG and EMG signals are acquired at 500 Hz, 625 Hz or 800 Hz.