Testing of the airflow sensor honeywell AWM42300V for using it in spirometer

Objective: AWM42300V of Honeywell Inc. is a small-scale airflow sensor which allows using it in intelligent carry-on spirometer designing. There is a problem that this sensor (AWM42300V) measures airflows which are considerably smaller than breathing airflow. Thus, an estimate of airflow measurement is possible only when the bypass interconnection is used. Methods: During the working progress the metering tube was assembled, the software for data transferring from sensor to computer (using the USB HID) and showing it on PC was developed. Due to bypass interconnection of the sensor and measuring tube the ability to measure desired amount of airflow was achieved. Then a calibration and testing of the instrument via metering equipment using rotameter RMF-25GYZ were carried out. Results: Some experiments, where the airflow with fixed known velocity was created, were carried out to estimate the measuring accuracy. The first experiment: 5 measures of different known airflow velocities were compared with values measured by means of RMF-25GYZ. The relative error was less than 4%. Second experiment: some fixed airflow velocities were measured 10 times. The highest value of experimental standard deviation achieved by single results in a range of measures was equal to 0,07 m/sec. Significance: The relative error value conforms to standard value for spirometry that equals to 4%. Small mean experimental standard deviation value of single results in a range of measures underlines achieved reproducibility. Findings can prove the ability of using the airflow sensor AWM42300V of Honeywell Inc. in spirometer design.