FFT requirements of real time signal from sensors I have an electrical current sensor which generates measurements every second. I want to calculate the FFT of this signal. Since my real-time values are received every second, I think that the fastest I can go with the FFT sampling period is also 1 sec. In that case, what I am basically doing is that I collect X number of samples in a buffer and I calculate the FFT. I then store the new values as they arrive at the end of this buffer and repeat the FFT calculation.
Q1: is this a correct setup?
Q2: is there a minimum requirement for the buffer (FFT window?). I have now set it up to process 10 samples.
Q3. what is the maximum number of frequencies that can be detected in this scenario?
Q1: is this a correct setup?

I'm guessing &quot;no&quot; but that really depends on your application and goal. The process will produce numbers but if these numbers are useful or not depends on what you want to do with them.

Q2: is there a minimum requirement for the buffer (FFT window?).

Mathematically speaking : no. You can run a FFT on a single sample if you want to. t doesn't do anything useful but it can be done. The real requirements come from your application.

I have now set it up to process 10 samples. Q3. what is the maximum number of frequencies that can be detected in this scenario?

An FFT setup like this will you give  you ten numbers which are the complex amplitudes from -0.5Hz to +0.5Hz in 0.1 Hz steps. That's not the only frequencies you &quot;detect&quot; but that's a more complicated topic. If you feed a 0.15Hz sine wave in the process all 10 numbers will be non-zero.
You may also get significant aliasing with this setup, if you don't use a decent anti-aliasing filter before the current sensor.