Fig. 6.

Performance evaluation of mask with micro-controlled flexible humidity sensor (CNT@CPM-3) for respiration measurements. a Photograph of a volunteer wearing respirator mask with the sensor fixed to monitor respiration. b Real-time respiration measurements of deep breathing. c Response of signal variations for different respiration. d Variation in relative response over time during respiration and voluntary apnea. e Detection of the rate and strength of an adult breathing via the mouth and nose (f) Photograph of the wearable device and actual operation for respiratory monitoring subject (g) Real-time respiratory monitoring results of a volunteer during cycling; Compared according to the intensity of exercise using ventilation system. (10 m∙s^-1; mild condition → up to 25 m∙s^-1; harsh condition → 10 m∙s^-1; mild condition)