SpO2 sensor embedded in a finger ring: design and implementation

A novel concept of Oxygen Saturation (SpO2) sensor embedded in a finger ring is presented in this paper. Due to the mechanical conception of the probe, the sensor fits any finger topology and assures a constant force applied to the phalanx. Ambient light artifacts are rejected at the analog electronics level. Finally, an innovative distribution of light sources and detectors and a dedicated signal processing procedure resolve the anatomical heterogeneity of different phalanx topologies, compensate low perfusion indexes due to the phalanx anatomy and estimates equivalent pulse oximetry SpO2 indexes. First in-vivo validation results of the novel sensor are discussed at the end of the paper.