Originally Posted by
wnl256
I don't know for certain but I can take an educated guess. The Snap measures power likely by sensing the resistance (physical, not electrical) against the roller. This resistance is not constant: it will be highest when you are on a downstroke and lowest when you are at the bottom of a stroke. So, measure the instantaneous resistance and count peaks per unit of time, then divide by 2. Voilą, you have cadence.
Good "guess!" Sounds very reasonable to me. Maybe I'll add a cadence counter and heart monitor, as well. I think heart rate might be good to know.