Hello! I've been looking on how to do a FFT on arduino but it seems impossible! Apparently I need to download a library and then design a code. I saw the examples on the arduino website but its useless because I can't download the library. Is there a library I can download and like pointers I can get in writing the code? What I'm trying to do is take a sound signal using a microphone, and split that noise in high and low frequencies to control LED lights.