One heartbeat signal from Polar Chest Strap displayed in Audacity with Beat Finder marking.
Four heartbeats captured from a Polar Chest Strap displayed in Audacity using Beat Finder
Recording the signal from a heart rate monitor like Polar or Pro-Form using the Polar Heart Rate Module - RMCM01 from Sparkfun proved less complex than other techniques. Here is one of the best:
diy-ecg-machine-on-the-cheap
Audacity Beat Finder converted the audio signal into a text file of with every R-R interval time, and that signal is as accurate as an EKG.
The breakthrough came from this article. The Kubios software installed efficiently on both Windows and Ubuntu.
The details and pictures will follow. Budget Biofeedback has a table at the Ann Arbor Maker Faire on June 6, 2010. See you there.
