Honestly it shouldn't be over your head. It's true deriving the the RC time constant formula involves calculus. However using it to get a capacitor value in this case only requires solving for a single unknown using algebra. This is only 7th or 8th grade math, and you've demonstrated a grasp of mathematical concepts at least as, if not more, difficult in this thread.
I never took calculus nor have I seen that equation before, so I didn't have any background info on what was what. (I'm still new to AC concepts and combining them with DC and whatnot). Thats what I meant by over my head. lol
DC is basically zero frequency, but the confusion is really my fault. I'm an EE that doesn't work with audio much. Off hand, I do know that the range of human hearing is kilohertz in magnitude, but I didn't double check the exact range. So for my example in an effort to get something that would yield some fairly easy numbers, I ended up choosing a frequency for the high pass filter that would actually exclude the entire audiable range for most human beings. smiley-red The math is still sound, but you probably want to try something around 20 Hz , 0.05 seconds, instead.
The corrected example:
? = R * C
? = 0.05 s (20 Hz, inverted)
R = 8000 ? (lowest possible load is the worst case)
Solve for CC = 0.05 s / 8000 ? = 6.25 ?F
Ah, that will be of much help. I picked up a few caps from radioshack(way overpriced, if not for my discount) and I will give them a try tonight.
It's my understanding that we were discussing overlaying AC on the DC power, not on any of the wires going directly I/O (should never be done because the Arduino microprocessors can only withstand about -0.5 V on these pins). If that is correct, the communication between the Arduinos will be on another wire or using wireless radio. Therefore, barring electromagnetic interference (which can be mitigated if it occurs), this AC signal shouldn't affect the Arduino serial communication by either means.
That is correct, I will isolate the Arduino IO pins from any AC signal. The onboard ardy is going to control each pickup's(what I call presence: fades between full series to a ratio of series/parallel/bypass then to a bypass state.) and will also control the LEDs on it(vine fretboard hollowed out and has RGB LEDs in it; should look good I think). The mcu will only share a communication and power line with the actual guitar's signal.
One thing though I hadn't thought of earlier. FM signals, dependent of amplification power, potential distance will vary. But if its through a shielded wire directly to a reciever, would there be such a distance factor? Or is a 'typically' low distance longer than about 30~ feet?
EDIT:
I tried with a few different size caps, and the dc signal still cuts out any sound. I even tried up to 300uf in caps both parallel and series. The only thing that would make sound is when I would have atleast 200uf and be connecting another cap. When the leads would touch it would make a sound kind of like plugging in a guitar. So I think I may be getting closer, but how much higher would I need to go? Or is there another aspect I may be missing?