Robots w/Lasers

July 17, 2007

Heart Monitor for NDS

I have a prototype of the hardware side of my Nintendo DS-based heart rate monitor. I’m using the awesome DSerial to interface an IR LED & IR phototransistor to the DS.

It works ok, but the signal is not strong enough. Slight movements can make the data unusable. I think I need to work on either amplifying the signal, or increasing the sensitivity of the DSerial. Also I need to rig up some velcro to stick the sensor to your finger, so you don’t have to hold it in place.

Here you can see my “sensor”:

Here is the connection to the DS:

And finally, here is a screenshot of the DS’s lower screen, which is just graphing the data coming from the DSerial’s ADC:

Check out this movie of it in action: dserial_heart_monitor.avi (1.5MB)

Filed under: DSerial,Hardware,Nintendo DS — davr @ 12:29 pm


  1. Wow! Another great step in the history of DS homebrew! Keep up the development, and I look forward to the release!

    Comment by Dragon042 — July 18, 2007 @ 10:29 am

  2. Great Idea.
    Most of the IR Heartmons Enclose the the Detector to prevent daylight interference. This also holds the unit still.
    The angle of the Detector and Emitter will also make a lot of difference to the signal.

    I like it already.

    Comment by Santa — August 7, 2007 @ 7:10 pm

  3. How about a new Tetris :

    Comment by Ben — August 29, 2007 @ 7:30 am

  4. Notes to myself on a better heart rate monitor to interface with the DS, instead of my ghetto IR sensor with wire leads connected to the DS:

    wireless ANT receiver with serial interface – $25
    strap-on wireless heart rate monitor – $38

    Comment by davr — July 14, 2008 @ 5:43 pm

  5. Looks cool!! it would be necessary if you want to see hows your heart…

    Comment by Fero23 — July 24, 2008 @ 4:58 pm

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