You need to use the line in level (normally 1v peak to peak RMS) from a CD / Tape deck. You then need to make a filter fo that the peaks provide a cleaner input (well at least thats what I used form my disco light project).
The attached image shows the filter I used to input the signal into an 877 PIC. I can't post the code as it was written in JAL (before I discovered PBP) but works on the pinciple of converting the voltage to a value between 0 and 254, and then making pin on the output port go high, so for example, if the input equated to 120 the first four pins RB0 - RB3 would be made high. Its not quite a true VU or Peak level meter, and I'm sure with re-coding you could do something better, but the effect to a decent track with lots of quiet bits between the beat looks cool
Bookmarks