This is the Pulslogger – Polar Edition!

This project came to be because of bored dome. I had nothing to do and came across the Polar Heart rate surface mound module at Sparkfun. I already had a polar heart rate monitor lying around so I decided to try it out.

I ordered the parts from a local reseller and the project was born. At the time I was working with the AT91SAM7X series from Atmel in other projects so it was quite simple to start up the project.

I know now that I made the project whey to complex, but hey, that how we learn. I decided to log all the heart rate data to a SD card connected to the microcontroller. By using USB MSD (mass storage device) I could access these files from a computer very easy.

The next step was to make the logger portable and that ment battery! Sparkfun also provided the lithium batteries needed with simple USB charge possibility.

The simplest whey to store data is in the CSV format, because it can easily be imported to Excel for calculations. And that’s why I went for it.

I needed a program to easily display the data and not need to calculate it every time I have logged my heart rate. I made a simple C# program to parse the CSV file and display it in a graph.

The final product can log infinite measurements (okay until the SD card runs out of space). The current limit of the device is the battery life; it can run constantly for about 2,5hour until it has to be charged again. This can definitely be optimized for longer lifetime, but hey I don’t exercise more than 2,5 hours, so it’s enough for me.

As you can see the small device can be attached to the Polar transmitter with ease. And do not interfere with your workout.