Accelerometer App

[JohnE]

Has anyone carried their smartphone while riding with the Accelerometer app turned on? It looks like it records triaxial (X,Y & Z) acceleration. The purpose might be to capture maximum acceleration at the apex of a turn. It's unlikely that that max acceleration would be purely X, Y or Z but some combination. I kind of forget but there is math involved in summing the 3 axes. 

Has anyone done this? Is it interesting?

[Jarcode]

For kinematics, net acceleration at the "crux" of a turn would be a combination of gravity, slope, friction, and normal forces. The way you would represent this vector using cartesian coordinates certainly results in a "combination of X, Y, and Z".

Strictly speaking, "acceleration" requires a direction. If you're looking for the magnitude of a vector, you want sqrt(x^2 + y^2 + z^2). If you want to translate the result into fancy "G force" terms, divide by 9.8.

 

[TimW]

Some people have done this, see the thread below:

 

 

[b.free]

GoPro allows you to count G forces more or less properly.

 

Edited November 10, 2022 by b.free

[Corey]

7 hours ago, Jarcode said:

If you want to translate the result into fancy "G force" terms, divide by 9.8.

...If using Metric. US customary unit users need to use handy units like Slug*mile/fortnight or something like that.  Ask the NASA Mars Climate Orbiter team for help. 

6 hours ago, b.free said:

GoPro allows you to count G forces more or less properly.

 

That's cool! There's so much to look at. I watched it a couple times. 

[JohnE]

9 hours ago, Jarcode said:

For kinematics, net acceleration at the "crux" of a turn would be a combination of gravity, slope, friction, and normal forces. The way you would represent this vector using cartesian coordinates certainly results in a "combination of X, Y, and Z".

Strictly speaking, "acceleration" requires a direction. If you're looking for the magnitude of a vector, you want sqrt(x^2 + y^2 + z^2). If you want to translate the result into fancy "G force" terms, divide by 9.8.

 

Thanks for the physics refresher. It's been a long time since college. Probably have to download the data into a program to do an ongoing calculation to find the max acceleration as you descend a slope. 

I think a phone in a pocket would show a better representation of what your body is experiencing that a smart watch. The watch would show the acceleration of your wrist which is likely higher frequency / higher amplitude than your body.