Audio input and waveform analysis

hi, firstly i'm new arduino forgive me if doesn't make sense.

what i'm trying have sound input ipod or mp3 player arduino drive set of motors waveform of music. know can thorugh processing don't want have arduino attached it. arduino atmega328 if makes difference. doesn't need exact people can see it's reacting music.

any on great.

well, want feed sound output 1 of arduino's analog input pins; once you've done that, can use analogread() function voltage level (corresponding waveform's voltage reading) value 0-1023 integer variable. once have stored in variable, tricky part (but code exist out there - somewhere) feed values (as small array of integers, imagine) fft algorithm/function, in order process waveform sampled whatever number of frequency bands desire; there can use levels drive whatever other code need.

now, audio input tricky - gonna want measure it; should around 1v peak-to-peak regular line-level outputs, can vary. ac waveform, can't feed directly analog input (well, can, clip negative voltage levels - giving half of waveform); must raise level of signal above 0 volts (called dc offset); not sure, should possible putting bit of voltage on pin itself, after bypass capacitor (inline source, between source , pin):

[font=courier]               +v offset
audio             |
source ----||-----+-----------> arduino analog pin
         bypass
           cap[/font]

the offset should 1-2 volts. measure signal before , after bypass cap o-scope verify waveform above 0 volts.

hope helps!

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