“Implementing a pulse oximeter using PYNQ and the Click HR4 sensor.
Introduction
Even before the Covid-19 pandemic, when I created my list of projects for the year, I included one which would look at oxygen saturation. Given the current pandemic it has become even more interesting to look at creating such a project.
In this project we are going to examine how we can use PYNQ and its high level frameworks to configure and control the Click Heart Rate 4 sensor using the Ultra96.
This Heart Rate click will provide us information on the oxygen saturation in the subjects blood using different LED wavelengths.
The resulting waveforms can be processed to extract not only the heart rate of the subject but also the oxygen saturation.
Of course, it goes without saying this project is for understanding and education and not intended to create a medical device.
Photoplethysmography
We can measure a subjects heart rate and Oxygen saturation using reflective pulse oximetry. This techniques uses different wavelength LEDs which illuminate the skin (normally a finger). The reflected signal is then monitored for changes in light absorption, the resulting signal is call a photoplethysmography of PPG signal.”