Hardware and Protocol for Testing of Piezoresistive Pressure Sensors for Pulse Wave Monitoring

Wearable, flexible piezoresistive pressure sensors show significant promise for applications like electronic skin, robotic limbs, and cardiovascular monitoring. Despite this, their broad utilization is constrained by durability and robustness issues. This letter introduces a novel testing technique and hardware setup to practically evaluate these sensors. Essentially, the hardware consists of an automatic clamp with a stationary and a movable component, driven by a stepper motor through a screw mechanism. A specialized gear assembly translates the screw axis rotation into an encoder for precise temporal measurement of applied pressure. The testbed evaluates sensitivity and durability within a pressure range of 0–30 kPa (with 25 Pa resolution), making it valuable for sensor developers. The incorporated pressure sensor exhibits a sensitivity of 0.93 kPa⁻¹ (5–12 kPa), response time of 261 ms, and durability up to 10 000 cycles. Apart from testing for key sensor properties, the testbed can generate modulated pressure, simulating a wide variety of blood pressures and heart rates. This feature establishes it as a vital tool for validating sensors for wearable pulse wave monitoring. As the result, the testbed provides a cost-effective solution to validate the wearable operation of flexible piezoresistive pressure sensors, eliminating the need for costlier equipment such as force gauges and sourcemeters.