Artifact-resistant, power-efficient design of finger-ringplethysmographic sensors. I. Design and analysis

摘要

A miniaturized, telemetric, photoplethysmograph sensor forlong-term, continuous monitoring is presented in this paper. The sensor,called a “ring sensor”, is attached to a finger base formonitoring beat-to-beat pulsation, and the data is sent to a hostcomputer via a RF transmitter. Two major design issues are addressed:one is to minimize motion artifact and the other is to minimize theconsumption of battery power. An efficient double ring design isdeveloped to lower the influence of external force, acceleration, andambient light, and to hold the sensor gently and securely on the skin,so that the circulation at the finger may not be obstructed. In thispaper, the basic concept of mechanical and electrical design isprovided. Total power consumption is analyzed in relation tocharacteristics of individual components, sampling rate, and CPU clockspeed. Optimal operating conditions are obtained for minimizing thepower budget