HearTec: An Embedded Dual-Site Oscillometric Platform for Blood Pressure and Arterial Stiffness Monitoring - Design and Preliminary Feasibility Study.

Arterial stiffness is an independent predictor of cardiovascular risk, yet traditional blood
pressure monitors are inherently unable to assess it, since they perform only single-site,
single-cuff measurements and do not capture the pulse wave propagation dynamics required
for its estimation. Existing systems capable of arterial stiffness assessment remain expensive,
bulky, and confined to specialised clinical settings, limiting their accessibility for routine or
personal use. This work presents HearTec, a compact and low-cost biomedical instrumentation
platform for dual-site oscillometric acquisition at the brachial and ankle locations, designed to
be affordable enough for personal use outside the clinical environment. The system integrates
synchronized pneumatic modules, piezoresistive pressure sensors, and dedicated analog front end circuits designed to separate DC cuff pressure from AC oscillometric pulsations. A key
hardware contribution is the implementation of a dual-solenoid-valve pneumatic architecture
enabling active stabilization of cuff pressure at the mean arterial pressure (MAP), which
provides a stable window for reliable waveform acquisition and pulse transit time analysis.
The embedded platform, based on an Arduino microcontroller, performs pneumatic control,
conditioning circuits, and wireless data transmission via Bluetooth with simultaneous local
storage. These preliminary results demonstrate the technical feasibility of signal acquisition
only; they do not establish the clinical or physiological validity of the estimated parameters
and do not constitute a clinical validation.&#xD.