Educational BoosterPack 8 bit FFT Spectrum Analyzer Attempt

[simpleavr 399]

@@sq7bti

 

I want to try the hamming window. I am on a 16 sample configuration though (It's a breadboard 8x8 matrix led display). Can I just use your code and skip every other value in the "hamming" array?

[sq7bti 20]

Hi @@simpleavr,

 

You might try to hand pick values from wider window, but here are Hamming windows size 16 (mind the symmetry):

// round(255 * window('kr',16,6))
//const unsigned char hamming[8] = ( 4, 18, 46, 86, 136, 187, 228, 252); //, 252, 228, 187, 136, 86, 46, 18, 4 );

// round(255 * window('kr',16,4))
const unsigned char hamming[8] = ( 23, 51, 88, 130, 172, 210, 238, 253); //, 253, 238, 210, 172, 130, 88, 51, 23 );

// round(255 * window('kr',16,2))
//const unsigned char hamming[8] = ( 112, 141, 170, 196, 218, 236, 248, 254); //, 254, 248, 236, 218, 196, 170, 141, 112 );

More information regarding window function you will find in Scilab help.

 

S.

[simpleavr 399]

@@sq7bti

 

 

Thanks for running the numbers for me. I google this hamming window thing and although I don't really understand the details (not trying to, too lazy), I know it will do good to my project. Will show everybody how it turns out.

 

Thanks again.

[simpleavr 399]

Happy holidays! It turns out great.

 

 

Button press cycles through sleep, 1 dot, 2 dots and 3 dots.

 

Press and hold for cycles through the following 3 menu options

Hamming windows choice; none, low, mid, high (via short presses)

Dimmer choice; 0...3

Sampling rate; 0...7 (0 is fastest)

 

This is the smallest spectrum analyser I built.

I managed to use 1 gpio for ADC, and left 15 pins for the 8x8 matrix (63 pixels used).