=== Arduino FFT Libarry ===
==== #Define options ====
These values allow you to modify the FFT code to fit your needs. For the most part, they just turn off stuff you aren't using. By default most functions are off, so you will have to turn them on to use them. You must also declare these #defines before the #include statements in your sketch.
'''FFT_N''' - Sets the FFT size. Possible options are 16, 32, 64, 128, 256. 256 is the defualt.
'''SCALE''' - Sets the scaling factor for ''fft_mag_lin8()''. Since 8b resolution is pretty poor, you will want to scale the values to max out the full range. Setting SCALE multiplies the output by a constant before doing the square root, so you have maximum resolution. It does consume slightly more resources, but is pretty minimal. SCALE can be any number from 1 -> 255. By default it is 1. 1, 2, 4, 128, and 256 consume the least resources.
'''WINDOW''' - Turns on or off the window function resources. If you are not using ''fft_window()'', then you should set WINDOW 0 (off). By default its 1 (on).
'''REORDER''' - Turns on or off the reorder function resources. If you are not using ''fft_reorder()'', then you should set REORDER 0 (off). By default its 1 (on).
'''LOG_OUT''' - Turns on or off the log function resources. If you are using ''fft_mag_log()'', then you should set LOG_OUT 1 (on). By default its 0 (off).
'''LIN_OUT''' - Turns on or off the lin output function resources. If you are using ''fft_mag_lin()'', then you should set LIN_OUT 1 (on). By default its 0 (off).
'''LIN_OUT8''' - Turns on or off the lin8 output function resources. If you are using ''fft_mag_lin8()'', then you should set LIN_OUT8 1 (on). By default its 0 (off).
'''OCTAVE''' - This turns on or off the octave output function resources. If you are using ''fft_mag_octave()'', then you should set OCTAVE 1 (on). by default it is 0 (off).
'''OCT_NORM''' - This turns on or off the octave normilisation feature. This is the part of ''fft_mat_octave()'' that divides each bin grouping by the number of bins averaged. Since a lot of sound sources are pink noise (they drop off in amplitude as the frequency increases), the scale tends to drop off rather quickly. This artificially boosts the higher frequencies when off (OCT_NORM 0). By default, the normilisation is on (OCT_NORM 1).