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This project provides an Arduino sketch that can power an Arduino + Ethernet Shield (or Arduino with built-in ethernet) to make a stationary bike computer that can upload Cycling workout sessions results to Runkeeper's Healthgraph API, where it get added to the user's activities feed. The activity can then be posted to Twitter or Facebook automatically by Runkeeper.

It doesn't need to be connected to a computer for that purpose, only a wired ethernet connection + DHCP is required.

It'll also display either current speed and total distance or average speed and elapsed time during normal use via a LCD.

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

The elapsed time only counts 15 seconds chunks when there was some activity, otherwise it'll pause.

If the pause last more than 5 minutes, it'll upload to Runkeeper the:

  • Starting Time
  • Total Distance
  • Elapsed Time

for the current session. From this, Runkeeper computes the average speed, pace and total calories burned.


Plug the ethernet cable and the USB/Power cable in. The Arduino will beep once it has obtained the current time and is ready for use.

Pedal away and it'll display the current speed while cycling between the total distance. average speed and elapsed time.

Stop pedaling for ~ 15 seconds and the pause screen will come up. 60 seconds, the lcd's backlight will be switched off. 5 minutes and it'll end the session and upload the result or discard the session if the "valid activity" threshold hasn't been reached.

It'll beep every 5km by default.

To start a new session, just use the bike again, it'll start over.

In action


Device in clear enclosure Prototype during testing

Runkeeper's screenshot

Runkeeper screenshot

Reed Switch (at the top of the picture)

Stationary bike's reed switch and magnetic brake


You'll need:

  • Runkeeper user account
  • create a Runkeeper app to get an access token (See below)
  • Arduino Uno + Ethernet shield or equivalent
  • 16x2 LCD
  • Stationary bike with a reed switch
  • Time library
  • HTTPClient library

The reed switch needs to be plugged in Pin2 to use the Arduino's hardware interrupts.


The Fritzing Schema file is available in the Schematics directory. Here is the breadboard view:

Breadboard view


You'll need to modify/provide the MAC address and Healthgraph's access token in the config.h (that you'll copy from config.h-dist) file. You might want to change the number of meters per reed switch activation too.

How to get access token

First, once you have your Runkeeper account got to:

Fill in the "Application Name", "Description", "Organization", select "Activity Tracking" and "Estimated Date of Publication".

You'll get a "Client ID" and a "Client Secret".

Open in your browser:

Replace XXX with your "Client ID". Authorize your application and it'll try to redirect you to an invalid page but you'll just need the authorization code you'll find in the url bar.

Now, in a shell:

curl \
-d "grant_type=authorization_code" \
-d "client_id=XXX" \
-d "client_secret=XXX" \
-d "redirect_uri=http%3A%2F%2Flocalhost%3A3001%2Fback"

Please note that the 'redirect_uri' needs to the be exact same one as before.

It'll then give you the access token you can use in your Arduino's code.

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