In the previous article I showed you a device for visualize your breathing. In this article I will show you how to use it as a sleep breathing recorder in order to detect hypopnea and apnea.
For it, I have just connected the microcontroller arduino to the PC with a USB cable and use two software. One for recorded the breathing curve and one for read it. The first soft is coolTerm it recorded the pressure data in a .csv file. The second is a web app called chart studio ploty which can read easily and quickly the .csv file. You can also read the .csv file with Excel but it is slow to open.
This is the breathing curve in chart studio ploty, you can zoom and navigate in order to see the entirely night sleep and detect apnea events. The y axis (vertical) represent the pressure in Pascal (pa), the x axis represent the time but the unit is not second nor millisecond. However, you can estimate the time by the frequency of breathing, at night we breathe around 10 time per minute, so one breath every 6 second.
The main problem is that you should count every apnea manually, there is no algorithm to do that. In sleep clinic they use a dedicated software to count apnea and hypopnea, they also have others data like brain waves, sound, oxygen saturation and others things. Maybe at home you can complete this device with an oxygen saturation recorder.
That's it for this article ...