WOW dude, that's exactly what I meant, thanks for the diagram. Actually you have to use a 1 ohm resistor, that way you don't have to divide the current by anything, (the easy way) ;D but if you don't have one, then you can use any resistor, and then divide the voltage you get by the resistance of the resistor, e.g. if it's a 5 ohm you divide by 5, if it's 7 then you divide by 7, etc.