Design and development of thermistor based sensor for spirometry

This paper presents the design, implementation and measurements of a spirometer based on thermistor based sensor. Respiratory variations are present in the electrocardiogram (ECG) and the photoplethysmogram (PPG). The aim of this study was to investigate these variations in healthy subjects during rest and invoked blood pressure changes. The primary goal was to develop a non-invasive respiration monitor. Significantly higher error rates were found in hypotension and hypertension. Airflow monitoring is an effective way to diagnosis sleep disorder that are caused by complete or partial cessation of breathing during sleep. For monitoring airflow, tempearature of thermistor and resistance of thermistor changes because of airflow. Designed sensor using glass type and bead type thermistor of 1k, which is use for measurement of respiration rate. By compairing these two thermistor LM35 used as sensor. After signal conditioning measure respiration rate parameter such as FEV1 is volume of expired air and FVC is the total volume of air.