Using python and the great matplotlib library, I have made a little app that measures the hart rate and computes various heart rate variability parameters (such as rMSSD, pNN50, LF, HF). On the hardware side, the pulse sensor connected to an Arduino Uno microcontroller is used. Parts of the code are based on other open source libraries. I am also planning to release the code as open source.
Here is a screenshot of the app:
A few things still need to be worked out. For instance, the heart beat detection (which is made by the Arduino) is not perfect. A few percent of beats are misclassified – depending on the positioning of the pulse sensor.
Update: I have now uploaded the source code. You can find it on GitHub.