HeartGuard is a compact, AI-powered ECG monitoring system designed to capture high-quality cardiac signals and analyze them in real time, directly on the device. Built around the STM32F411CEU7 microcontroller and the ADS1298 8-channel ECG analog front-end, the system combines precision biosignal acquisition with on-board machine learning for arrhythmia detection. Power is supplied via a USB Micro-B connector, regulated by low-noise LP5907SNX-3.3 and LP5907SNX-1.8 LDOs to ensure clean analog and digital rails, while a TVS diode provides surge and ESD protection. ECG leads connect through a patient-friendly JST connector, with electrode placement following the Einthoven’s Triangle principle for accurate multi-lead acquisition. The PCB layout isolates analog and digital domains for minimal interference, with careful grounding and short signal paths to preserve signal integrity. With the schematic, layout, and BOM finalized, HeartGuard’s PCB is now ready for fabrication — the next steps will be assembly, initial firmware programming, and integration of the trained AI model.