“This is a project I completed for a biomedical instrumentation class at Vanderbilt University. This spirometer uses a pressure transducer and an Arduino Uno to compute the volume of air blown through the plastic tube. The circuitry is very basic- the majority of this project relies on the coding and an understanding of fluid dynamics. I’ll go through the set up of the physical circuitry and then delve in deeper to the code and mathematics. Spirometers are typically used in a clinical setting to diagnose pulmonary disease. These tools measure the amount of air expired, and in some cases, can show the change in flow rate over time. This simple, low cost spirometer allows for a rough calculation of the volume of air expired from the lungs over a period of time. A button on the Arduino LCD screen is used to control the period of time over which this calculation takes place. The results are clearly displayed on the LCD screen, making this a fun, easy to use device.”