This is a mechanical engineering question with its roots in Mathematics and so I felt this was the best stack exchange site to post my question.
In short, I have used a device to measure the magnitude of acceleration of my body every second that I walk. I am under the impression that I can find the natural frequency of the device if I take a fourier transform and look for a peak (this would be the frequency of my walking that resonated the device output). I am simply looking for verification if this is actually what a fourier transform would show? I have run an FFT over my data and I have a peak at the very low frequencies, but its only about 2 times as high as the next peak, which is roughly 1.5x as high as the next, etc. So from this I have one of two conclusions, a) my methodology with the FFT is incorrect, or b) I never excited the device at my walking frequencies.
Thank you for your advice.