http://openenergymonitor.org/emon/buildingblocks/how-to-build-an-arduino...
void setup()
{
Serial.begin(9600);
emon1.current(1, 111.1); // Current: input pin, calibration.
}
void loop()
{
double Irms = emon1.calcIrms(1480); // Calculate Irms only
Serial.print(Irms*230.0); // Apparent power
Serial.print(" ");
Serial.println(Irms); // Irms
}
Re: How do I calculate Ampere or Watts from this Arduino setup when voltage is known?
With that sketch, you have amperes and an estimate of apparent power (VA). You cannot have real power (W). You need to use the ....voltage sketch instead. See the Github link at the top of the page? Go there and download a fully engineered sketch, or try looking a little further down Building Blocks.
Re: How do I calculate Ampere or Watts from this Arduino setup when voltage is known?
So the IRMS is the Ampere?
I used wrong resistor so assuming my measurement is not accurate but Ampere will do.
Re: How do I calculate Ampere or Watts from this Arduino setup when voltage is known?
"So the IRMS is the Ampere?" Of course. I is the international standard abbreviation for current, the standard unit being the Ampere; rms is an abbreviation for root mean square - the average value of an alternating wave that has the same heating effect as a direct current of the same value.