Prototyping a Pulse Oximeter
As part of our laboratory module, my lab partner and I decided to take on the microprocessor course that consisted in a first part where we learned the basics of Assembly and a second part where we had develop a project using a XXXX microchip. We decided to build a Pulse Oximeter.
In 2020-2021 due to the COVID-19 pandemic, teaching has been remote. Overall the situation was far from ideal: to begin with, my lab-partner and I were located in different countries and had to work together on Microsoft Teams. However, the department provided us with all the required lab equipment (“lab-in-a-box”). This meant that we were able to use the device we built to track the heart rate during a night of sleep.
If you want to know what we found out, skip to the last section. Otherwise keep reading and I will give a couple more information about the pulse oximeter we prototyped.
Our device
Hidden in a night of sleep
My lab partner and I decided to try and use the pulse-oximeter for something that could potentially be interesting. We were aware of the idea that sleep goes in cycles with a duration of approximately 90 minutes: could we use the pulse oximeter to see some traces of this process?
Method
We connected the pulse oximeter’s microchip to a computer via $\mathtt{USB}$ and we opened a $\mathtt{UART}$ communication protocol. Data were sent by the pulse oximeter, collected by a Python script which we ran on the computer and saved locally into $\mathtt{.txt}$ files.
Then, we connected the author of this blog to the pulse oximeter sensor and started recording his heart rate. The next morning we were delighted to find out that the extremely dodgy setup held during the night and that we managed to collect a set of good data.