I'd have to use a digital pin anyway to detect the external sensor, so I don't really see the point in using an extra component?
I'm trying to send 24V AC to an Arduino digital in. I have a separate power source, sorry for the confusion.
My question about the wall warts was whether the output was just a function of the input or if it was only a specific voltage. If input is 120V AC and output is 6V DC, would 60V AC yield 3V DC? if that's the case, 24V AC would yield a little over 1V DC.
I think I'm actually going to go with the rectifier + capacitors. Do I need the voltage regulator if I use a voltage divider?