ESP32-S3-Based Multimodal Wearable for Remote Vital-Sign Acquisition with ECG-to-PPG Pulse-Arrival-Time Tracking and Functional Cloud Triage: An Engineering Proof of Concept
TL;DR
The work demonstrates an end-to-end low-cost remote-monitoring proof of concept spanning wearable sensing, dual-core firmware, cloud storage, role-based dashboards, and human-in-the-loop triage and supports system integration and engineering feasibility.
Abstract
Highlights What are the main findings? A single ESP32-S3 supported synchronized ECG, PPG/SpO2, and contact-temperature acquisition while FreeRTOS isolated physiological sampling from network activity. System-level engineering verification demonstrated synchronized multimodal acquisition, functional propagation of tested synthetic critical scenarios, sub-second dashboard presentation in development logs, and automatic recovery from temporary Wi-Fi interruption. No human-participant data contributed to the results reported in this proof-of-concept manuscript. What are the implications of the main findings? The work demonstrates an end-to-end low-cost remote-monitoring proof of concept spanning wearable sensing, dual-core firmware, cloud storage, role-based dashboards, and human-in-the-loop triage. Clinical deployment requires prospective human-participant validation with reference-grade instrumentation, formal cuffless blood-pressure calibration and agreement analysis, reproducible classifier reporting, quantitative timing/reliability and power testing, and broader safety and cybersecurity evaluation. Abstract Continuous remote physiological monitoring requires low-cost sensing nodes to preserve timing fidelity while maintaining secure connectivity and interpretable escalation. This study presents an engineering proof-of-concept platform centered on an ESP32-S3 with AD8232 ECG, MAX30102 PPG/SpO2, and MAX30205 contact-temperature sensing. FreeRTOS separates nominal 100 Hz ECG/PPG acquisition from network communication, and the ECG R-wave-to-peripheral-PPG-foot interval is treated as pulse-arrival time (PAT). Telemetry is transmitted over authenticated HTTPS to a Laravel platform, while a separate FastAPI service provides human-in-the-loop normal/warning/critical functional triage. The current evidence is limited to bench-top engineering operation and synthetically constructed triage scenarios; no human-participant measurements are analyzed or reported. An ethics-approved rest-exertion-recovery protocol has been prepared for a future validation stage. The present results support system integration and engineering feasibility, while physiological accuracy, PAT-to-blood-pressure calibration, respiratory-rate agreement, classifier performance, timing reliability, and battery/power characteristics remain to be established quantitatively.