Measuring 5+v in Arduino Analog pins

How could I measure more than 5v in the arduino? I suppose it would be something along the lines of a resistor which would then need a conversion factor later...

rpmaurer:
How could I measure more than 5v in the arduino? I suppose it would be something along the lines of a resistor which would then need a conversion factor later…

Typically it is done using two resistors in series and is called a voltage divider. If say you had an external voltage that could be any value from 0 to +10vdc you could wire the signal to the top of the two series connected resistors (5k ohms each works well), wire the bottom of the lower resistor to the ground of both the signal source device and a arduino ground pin, and finally wire the junction of the two resistors to a arduino analog input pin. Then in your software you would simply multiply the reading by 2 to get the actual signal voltage value.

That make sense?

Lefty