Originally Posted by
Bald Paul
I looked at the specs and "tech" on the website for that thing, and cannot figure out how it's supposed to work based on speed, acceleration, cadence, and wind. For all it knows, if I'm moving the pedals (soft pedaling) and basically putting no power to the rear wheel while coasting down a steep hill, the device sees acceleration, an increase in wind speed, and movement of the crank and extrapolates a power number. I'm betting it would read much higher than my actual, crank based power meter - the one sans pitot tube, baro sensor, etc.
It has a barometric altimeter and a multi-axis accelerometer (so essentially it has an inclinometer). It doesn't have a built-in speed or cadence sensor; you can link those if you have them.
The idea and theory of these devices is solid; I use the same principles myself. In practice, the implementation of the theory to an actual product is less happy.