Hi,

What I am trying to accomplish is to build a delay device that turns on your amp a few secs after the radio is turned on. I have already built this using the amp turn on line from the stereo which is DC Voltage line. However for my brother's car, that I also would like to put this in, his stereo doesn't have an amp turn on. Due to this I need to use the speaker lead which is an AC voltage signal.

Orginally I thought that using a AC/DC converter on a microcontroller might do the trick, but on further inspection it turns out this is not the case. I am now thinking about building a simple PNP Transistor Switching Circuit where the AC Voltage signal (line) would be connected to the base and control the switching with a +5V DC voltage following to the PIC when the switch is closed. However, I am not sure if this will work.

Essentially the easiest way to characterize what I need to do is somehow have the PIC dectect when the AC signal is HIGH either directly or maybe through some circuit like a PNP Transistor switch. Once the PIC detects the line as being HIGH then it will delay and set the output HIGH.

I hope that this explains what I am trying to do a little better, and thanks for the help.

~Michael