I need to read the exact voltage

I need to read data from the voltage across the arduino, after having a read range of this form -> 4.15 volts 4.50 volts && -> this will send me a serial character by the Doors, and can read the character for an interface.

Sorry dharem but none of that makes much sense. I assume English is not your primary language (at least I hope so :)).

What character? What doors? Where does 4.15 and 4.5 volts come from? What's the AND operator (&&) got to do with it? What does "across the Arduino" mean?

Can you spell out the application in simple point form?


Rob