Fully Integrated Front-End CMOS-MEMS Transducer for Low-Cost Real-Time Breath Monitoring

Home and clinical breath monitoring is typically accomplished by either expensive and complex equipment or by basic manual methods such as chest wall expansions counting by visual inspection. However, the breathing rate represents a crucial metric to assess patient status while pattern abnormalities may be indicative of various health conditions. This work presents a low-cost front-end breath monitoring sensor developed for portable applications, providing ultra-fast response thanks to on-chip integration, suitable for straightforward signal processing, recording and/or transmission. The device is based on a CMOS-MEMS monolithic oscillator exploiting its high sensitivity to temperature and relative humidity to detect exhalation and inhalation. In addition, a specific baseline compensation algorithm has been developed to remove long-term sensor drift. Experimental evidence demonstrates real-time breathing monitoring from 4 bpm to 120 bpm, covering a whole range of emerging applications for e-health, home self-care.