I am planning to use an Arduino to make a joulemeter for a current range of 0-30 A and a voltage range of 0-24 V.
The voltage measurement is fine but I have questions about the current measurement. For measuring current, I plan on using a MAX4081TAUA+ to amplify voltage across a shunt.
The Arduino internal ADC can read up to 5 V and the voltage gain of the amplifier is listed as 20 V/V. From my understanding, at maximum current, the voltage across the shunt resistor should be 5 / 20 = 0.25 V, so the resistance of the shunt should be about 1 mΩ. Is this correct and will this give a reasonable accuracy?