Hello guys, I'm working on a project in which we are attempting to use the arduino fft library to detect frequencies that fall into a specific range. I've put some filters together to eliminate some of the unwanted frequencies, but was wondering anyone has any sample code that does what I am looking for. I have already looked at the sample codes provided from the fft and fht libraries, but they don't help me so much for what I am looking for.
Just a heads up, I'm relatively new to arduino programming so this is all pretty complicated for me anyway. If you can come up with anything it would be greatly appreciated.
but they don't help me so much for what I am looking for.
Why do you think that then? I would have thought it was exactly what you need. Just look at the bins that correspond to the frequencies you are intreated in.
Well, honestly it's not so much that it doesn't work for what I need, but that I don't completely understand how it works. Since I'm still relatively new to programming with Arduino, this has been kind of confusing.
So, just filter it down to the frequency of interest and take the absolute magnitude. If there's a signal remaining after the filtering, then it's your signal. No need for FFT.
The Teensy audio library contains lots of signal processing elements that may be useful. Even if you're not using a Teensy, you can copy the code and use it. (But buy a Teensy anyway, to support Paul's good work for Arduino.)
Signal processing, which includes frequency detection, is an advanced topic with an amazing variety of pitfalls. If you want to learn, expect to do some background study.
If you can come up with anything it would be greatly appreciated.
The very least you could do is give some useful details about the project.
Up to this point we have put together a filter to get rid of some of the frequencies out of the range we don't want. We have a range of 700 - 1800 Hz. The main thing I want to get out of the FFT is that I want for it to detect frequency, and after getting an input multiple times within a set time frame, display an output.
Could you be less precise?
I want for it to detect frequency
You are in luck! The FFT "detects frequency". Problem solved.