Picture of Web-enabled Polar Heart Rate Monitor
Use a Polar heart rate sensor, a cheap hardware board connected via USB and a little bit of software to put your heart rate on the Web. The live data is served right from your computer and made accessible via the Yaler relay (disclosure: I'm a founder of Yaler). Once you turn off the local service, the data is no longer public - own your data!

That said, the purpose of this project is of course to share your heart rate. My heart rate URL for example is (Note: you'll get a "504 Gateway Timeout" error or an empty page if my heart is not online.)

What you need:

- T31 coded Polar transmitter ( )
- Polar HRMI board from SparkFun ( )
- Mini USB cable (e.g. )
- Windows computer (.NET, not sure Mono works) connected to the Internet

So let's get started...

(Note: This project has been waiting in my Instructables drafts folder since March 2011. The setup was extended using a BlueSmirf Bluetooth module to increase range during the legendary 24 hour Pachube IoT Hackathon in April 2011, but I fear I'll never manage to document that part. So, here's the basic desktop version at least.)
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Step 1: Putting on the Sensor

Picture of Putting on the Sensor
To test the Polar heart rate sensor, you got to put it on. Moisten the contact area (see image) and strap the sensor around your chest.

Step 2: Connecting and Testing the Polar Board

Picture of Connecting and Testing the Polar Board
Once you got the sensor around your chest, it's time to test the sensor and the transceiver board. Connect the board to your computer via USB and wait.

If you are close enough to the transceiver (about 80cm max.) a greenish LED on the sensor board starts blinking. That means, your board and sensor both work.

If the LED does not blink, try moistening the sensor contact area and pressing the sensor tightly to your chest for a short moment.

For details on the transciever board and how to talk to it from Windows, see