Wireless Physiological Sensor System for Ambulatory Use

Abstract

A wearable physiological sensor system (PSS) has been built that can be used with a wireless control unit to monitor the physiological status of a mobile user. Two physiological variables, heart rate and respiratory rate, were selected for initial study. The PSS was required to be noninvasive, lightweight, and low-power. Initial studies indicated that heart rate could be effectively measured using infrared light technology and so this was implemented in a wrist strap. Respiratory rate was recorded using a novel implementation of conducting polymer strain gauges. For this purpose, polypyrrole-coated Lycra was fabricated and a chest strap was made that incorporated this sensor. Both sensors were connected to the PSS unit that was designed to provide the necessary signal processing; the output signals were then analyzed by the microcontroller in the control unit that is used to activate a wearable tactile display.