Easy workout logging with Ethernet-enabled exercise bike

It will be easy to keep your exercise routine on track if you don’t have to do anything at all to log your workouts. [Reefab] developed this add-on hardware for his exercise bike that automatically logs his workout on the Internet.

He’s using RunKeeper to store and display the workout data. They offer a token-based API which [Reefab] implemented in his Arduino sketch. The hardware to grab data from the exercise bike is quite simple to set up. A rare-earth magnet was added to the fly-wheel with a reed switch positioned next it in order to measure the number and speed of rotations. This is exactly how a consumer bicycle computer works, needing just one accurate measurement corresponding to how far the bike travels with each revolution of that wheel.

In addition to the networked-logging feature [Reefab] included a character display so you can follow your speed and distance data during the workout.


  1. Retroplayer says:

    Hmm… every hack like this that I have seen adds some type of RPM sensor on to the bike, even bikes that already have cheap digital monitors. Why haven’t I seen any where the person hacked into the sensor already there?
    I briefly looked at mine and it is just a square wave pulse that increases in frequency with RPM. Pretty standard. Getting a pulse on this line wakes up the CPU on the monitor.

    I haven’t hacked mine further than looking at the signals, but I wonder why nobody seems to be doing it that way.

    • wernicke says:

      Hmm… I believe he did hack into the sensor already there.

      from the description:
      >”The sensor used is the reed switch that was already present in my stationary bike connected to the Arduino with a pulldown resistor.”

      • Retroplayer says:

        Ahh… I didn’t even click to the original article because of this in the article description:

        “A rare-earth magnet was added to the fly-wheel with a reed switch positioned next it in order to measure the number and speed of rotations.”

        Which indicated that these components were added. Now I will have to take a look :)

      • wernicke says:

        fair enough. On the other hand, I didn’t bother to read had’s description and just clicked through to the original article. It seems that had sometimes adds their own details or just guesses in their summaries.

  2. David Sutherland says:

    Microsoft Health db?

  3. Alex Rossie says:

    I doubt I’d use this but the library use and the README.me is fantastic! Now I know how to beautify my readmes on github

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