I'm making some LEDs move to the rythm of the music (soon to be published :) ). I basically take the audio signal from the computer (3.5mm cable) and read it over the analog in. I then activate some TLC5941 LED driver.
Apparently, the driver chips are causing interference with the audio signal, because if I crank up my amplifier, I can hear a high pitched noise as soon as the chip's PWM kicks in. Also, sometimes when it's quiet, one LED will go on, it will interfere with the audio line, creating more noise, lighting more LEDs, and so on.
Question: How do I isolate my audio signal from something like that? Is the interference coming from the Arduino pin itself, or is it EM waves in the air around the driver chips? Could I use some kind of decoupling cap? Wrap the cable in aluminium foil? Any ideas? As I said, right now the audio goes directly into the analog port, nothing inbetween. Loooking forward to some answers!