Design and Evaluation of an IoT-Enabled ESP32 Photoplethysmography Monitor for Heart Rate and SpO₂

Muhhammad Iyan Putra Pratama (Teknik Elektro, Fakultas Teknik, Universitas Trunojoyo Madura)
Luthfan Hadi Pramono (Computer Engineering Department, Faculty of Information Technology, Universitas Teknologi Digital Indonesia)
Adi Kurniawan Saputro (Teknik Elektro, Fakultas Teknik, Universitas Trunojoyo Madura)
Dian Neipa Purnamasari (Teknik Elektro, Fakultas Teknik, Universitas Trunojoyo Madura)
Muttaqin Hardiwansyah (Teknik Elektro, Fakultas Teknik, Universitas Trunojoyo Madura)

Jurnal Teknik Elektro dan Komputer TRIAC
Vol 12, No 2 (2025): Oktober 2025

Cardiovascular disease (CVD) motivates affordable, continuous monitoring of heart rate and peripheral oxygen saturation (SpO₂). We present a single-MCU device using an ESP32 and MAX30102 photoplethysmography sensor that acquires heart rate and SpO₂ and streams data to a ThingSpeak dashboard. Performance was evaluated over four consecutive days under normal conditions, with five paired measurements per day against a clinically approved fingertip oximeter. Using all paired observations, the proposed design achieved low errors with RMSE = 0.84 bpm for heart rate and 0.59 percentage points for SpO₂, the maximum absolute error did not exceed 1 bpm or 1 pp, respectively. These results demonstrate end-to-end operation and good agreement with reference in resting conditions.