Cuffless Blood Pressure Estimation from Synchronized ECG and PPG Using Pulse Transit Time: An Embedded Acquisition and MATLAB Simulink Implementation

Cuff-based sphygmomanometry provides only intermittent readings and is poorly suited to continuous or wearable monitoring. This paper describes a low-cost cuffless blood pressure (BP) estimator that derives pulse transit time (PTT) from a single-lead electrocardiogram (ECG) and a fingertip photoplethysmogram (PPG). An AD8232 front end and a MAX30102 optical sensor are sampled at 200 Hz by an ESP32, which streams time-stamped samples over USB serial to MATLAB Simulink. The Simulink model filters both signals, detects the ECG R-peak and the PPG systolic peak, computes PTT beat by beat, and converts it to systolic and diastolic pressure with a linear calibration model whose slopes are negative. In a 30.43 s live recording the pipeline returned a PTT of 185 ms, pressures of 123.8/77.2 mmHg and a heart rate of 75.84 bpm. Against one simultaneous reference-cuff reading of 126/80 mmHg, the errors were −2.2 and −2.8 mmHg. This is a single-point plausibility check rather than a validation. Multi-subject calibration and accuracy assessment against the ANSI/AAMI SP10 criteria remain to be completed.