Application idea: Bicycle computer

Al Johnson openmoko at
Tue Dec 4 17:32:11 CET 2007

On Tuesday 04 December 2007, hank williams wrote:
> On Dec 4, 2007 7:39 AM, Neil Davey <neil at> wrote:
> >  If you are referring to the signal from the Polar straps, it is not
> > really a protocol...
> >  It is just a magnetic pules transmitted when the heart beat occurs..
> so is there a receiver chip one could buy to detect these magnetic
> pulses? I'm not quite sure how one goes about capturing that.

Not sure about the Polar units, but for things using ANT like the suunto 
cheststraps there are these:
Everything from chips to complete USB sticks. No linux driver for the USB 
stick yet, but they may be willing to release enough info for one to be 
developed. USB is probably easiest for connection to the Neo, while the 
modules should be fine for a wireless cadence sensor. Adding a wheel pulse 
should be fairly easy if you aren't happy with GPS speed. If you're feeling 
really adventurous you could strain gauge the crank to give you torque 
measurement, but that might eat your batteries.

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