Open-source low-cost non-contact ECG monitoring system using active dry electrodes

Continuous electrocardiogram (ECG) monitoring is essential for the early detection of cardiac arrhythmias and other heart conditions. However, conventional wet electrode-based systems often cause skin irritation and signal degradation, making them uncomfortable and unsuitable for long-term daily use. In this study, we present a fully open-source, low-cost (∼$14), miniaturized (∼50 × 35 × 28 mm³), and lightweight (∼60 g), wearable ECG monitoring platform that uses non-contact, active, dry electrodes based on capacitive coupling. The system integrates ultra-high input impedance electrode circuitry, an analog front-end integrated circuit, Bluetooth wireless communication, and an Android mobile application for real-time signal visualization and storage. Comprehensive validation shows that the system reliably acquires ECG signals through light to moderate clothing, with clear preservation of key features, such as QRS complexes, and accurate heart rate estimation. Comparative experiments with a commercial, clinical-grade ECG monitor demonstrate excellent agreement in rhythm tracking, and systematic module-level power analysis highlights further opportunities for low-power optimization. All hardware designs, firmware, and software are openly released to accelerate innovation and reproducibility in the field of wearable, non-contact ECG monitoring. The proposed platform provides a practical, extensible, and accessible reference for researchers aiming to advance next-generation cardiac monitoring technologies.