This project is open source heart rate monitor. I wanted a cheap way to log and graph my exercise data from my Polar T31 transmitter. Professional and ridiculously expensive modules exists, but did not give me the raw data and control I wanted. This project was inspired by humanapi.org and the maker philosophy (Adafruit). 

User license: feel free to use and share code with attribution.

If I were to restart this project today (already owning an Android w/Bluetooth and GPS), I believe that I would just get a Polar WearLink+ transmitter with Bluetooth (http://www.shoppolar.com/_polarususdenstore/cgi-bin/go.cgi/webstore/product?pid=F2222CB2JCAKW63JFVH) and log my information with Android (like http://store.endomondo.com/eu/polar-wearlinkr-transmitter-with-bluetoothr-193.html).

hardware:
Polar T31 transmitter
http://www.polar.fi/en/products/accessories/T31_transmitter
http://www.polar.fi/en/products/accessories/T31_coded_transmitter
Polar Heart Rate Module
http://www.sparkfun.com/products/8660
Aduino (UNO)
http://arduino.cc/en/Main/ArduinoBoardUno
Adafruit Data logging shield
http://www.adafruit.com/products/243

software:
heart-monitor.pde
https://github.com/luctussier/Heart-Monitor
libraries:
	Arduino SDK - http://arduino.cc/en/Main/Software
	SD - https://github.com/adafruit/SD
	RTClib - http://github.com/adafruit/RTClib