Thank You Nigel,
I realize I could use an optocoupler, such as:
The HCNW4562 analog optocouplers provide wide bandwidth isolation. Avago Technologies is a leading supplier of analog optocouplers, logic interface optocouplers and IPM interface optocouplers.
But that will add complexity to my system. It will require me to add an isolated 5V source to power the input side of the circuit, which I do not want to do.
I know such transformers exist, as I purchaed a part:
**broken link removed**
and cracked it open. As I suspected, its a transformer and a Cap, which is why it requires no external power -
I know this type of transformer exists somewhere, I just cant seem to find it. If you could offer any help in that direction, it would be most appreciated