Physical, Digital, and Embedded Analysis of a Microcontroller-Based ECG

This work presents the design and implementation of a microcontroller-based electrocardiogram (ECG) acquisition system that integrates biomedical principles with embedded electronics to address the growing need for portable, low-cost, and real-time cardiac monitoring solutions, particularly in environments with limited access to advanced diagnostic infrastructure. The ECG signal, originating from the bioelectrical activity of myocardial cells, is captured using electrodes, amplified by a high-CMRR instrumentation amplifier, then isolated via optocouplers and filtered with bandpass filters to remove noise while preserving diagnostic features. The conditioned signal is digitized by the PIC16F877 microcontroller's 10-bit ADC module, enabling precise sampling and conversion of cardiac waveforms, and transmitted via the USART interface, using the MAX232 driver, to a PC for visualization and analysis via a custom interface developed in Visual Basic .NET. This multidisciplinary system demonstrates how to design and build functional biomedical devices.