Numerical value for frequency

how can i get numerical value for frequency ??

I don’t completely understand your question, but here goes:
The plot below comes from SWARM. It shows a time record (top) a Fourier spectrum (middle) and a spectrogram (short-term Fourier transforms plotted as a contour map with time).
In the Fourier spectrum, frequency is the abscissa, having units of Hz or cycles/second.
In the spectrogram, time is the abscissa and frequency is the ordinate, once again in Hz.
Does this answer your question?

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Pardon me sir,actually i want to make a system using raspberry shake which will only recognise and generate alarm for rockfall event and nothing order than that,can you guide me on which parameters should i focus to generate alarm from particular frequency?