Study of PPG Sensor Positioning on Smart Eyewear for Biosensing

This study explores the best placement for pho-toplethysmography (PPG) sensors in smart eyewear, focusing on three anatomical points (nose, behind the ear, and above the ear). Using a controlled experimental setup with 10 sub-jects, the research assesses PPG signal quality through visual inspection, metrics analysis, and heartbeat estimation. Results consistently support the nose as the optimal location, offering superior signal quality and lower error rates than positions behind and above the ear. Moreover, from our results, infrared light enhances signal quality, and metrics like autocorrelation function and kurtosis index have the potential to effectively distinguish between good and bad signals, guiding PPG sensor placement. Despite limitations in signal analysis, the study sets the foundation for future advancements in wearable biosensing, and future research should explore advanced signal processing techniques and consider individual physiological variations for broader applicability.