Design of Lung Forced Vital Capacity Measuring Instrument with Flow Sensor

Flow measurement is a major problem which has to be resolved to get a good performance of a lung forced vital capacity measuring instrument with applying flow sensor. The purpose of this research is to design a lung forced vital capacity measuring instrument to measure the volume of lung forced vital capacity. The design of this lung forced vital capacity measuring instrument uses the yf-s201 sensor to measure the volume of exhaled forced vital capacity. The output of the lung forced vital capacity volume value and the lung forced vital capacity value graph could be displayed on the TFT LCD. Instrument testing is done by comparing the test value with a 3L capacity test tube and by comparing the value of the forced vital capacity of the lungs with the value of the forced vital capacity of the lungs measured using a spirometer and predicted values based on age and height. After testing with a calibration test tube, an error value of 0.12% was obtained. In the test results using the spirometer comparison instrument under normal conditions, an error value of 0.23% was obtained and testing by comparing the predicted value after running with an error value of 2.3%. From the results of testing the error value instrument is still within the tolerance threshold with a tolerance limit of
$\pm\mathbf{6}\%$
. The proposed method was useful for pulmonary disease diagnostics and screening by utilizing yf-s201 sensor as a flow sensor to measuring forced vital capacity.