Add emon lib for a later non invasive current sensor.

libraries/EmonLib/examples/current_only/current_only.ino

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+// EmonLibrary examples openenergymonitor.org, Licence GNU GPL V3
+
+#include "EmonLib.h"                   // Include Emon Library
+EnergyMonitor emon1;                   // Create an instance
+
+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
+}

libraries/EmonLib/examples/voltage_and_current/voltage_and_current.ino

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+// EmonLibrary examples openenergymonitor.org, Licence GNU GPL V3
+
+#include "EmonLib.h"             // Include Emon Library
+EnergyMonitor emon1;             // Create an instance
+
+void setup()
+{  
+  Serial.begin(9600);
+  
+  emon1.voltage(2, 234.26, 1.7);  // Voltage: input pin, calibration, phase_shift
+  emon1.current(1, 111.1);       // Current: input pin, calibration.
+}
+
+void loop()
+{
+  emon1.calcVI(20,2000);         // Calculate all. No.of half wavelengths (crossings), time-out
+  emon1.serialprint();           // Print out all variables (realpower, apparent power, Vrms, Irms, power factor)
+  
+  float realPower       = emon1.realPower;        //extract Real Power into variable
+  float apparentPower   = emon1.apparentPower;    //extract Apparent Power into variable
+  float powerFActor     = emon1.powerFactor;      //extract Power Factor into Variable
+  float supplyVoltage   = emon1.Vrms;             //extract Vrms into Variable
+  float Irms            = emon1.Irms;             //extract Irms into Variable
+}