A High-Sensitivity and Wide-Range FBG-Based Flow Sensor for Pulmonary Function Tests

With the continuous increase in the incidence rate of respiratory diseases, the importance of pulmonary function tests (PFTs) in early diagnosis and disease monitoring has become increasingly prominent. This paper proposes a high-sensitivity, wide-range flow sensor based on Fiber Bragg Grating (FBG) for pulmonary function testing. The sensor consists of 2 cylindrical covers and an internal flexible differential lever structure. By replacing rigid hinges with flexible hinges, it achieves airflow