Calculating Sea Wave Height Using Arduino and ADXL335

Projects General Guidance
1

Any suggestions appreciated ....

I'm trying to calculate the Ocean Wave Height using FFT and 3 axis accelerometer. My understating how to do it is :

I need to calculate the spectrum of A ( A=sqrt(ax^2+ay^2+az^2)) , by standard FFT function. This will give me the acceleration spectrum, Sa(f), which is the function of wave frequency, f.
To convert it to the more conventional elevation spectrum, Sz(f), I need to divide it by (2pif)^4, because acceleration of the circular wave motion is A=Z*(2pif)^2, while the spectrum is the squared magnitude, Sz~Z^2.

in brief the logic should be

2

Check this out, google is your friend

how to measure height using accelerometer

3

Will the accelerometer be bobbing on the waves? If so it probably won't follow the trajectory of a water "particle", i.e. it may not undergo simple elliptical motion.

It may be easier just to determine an empirical wave height versus acceleration relationship by experiment.