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Add emon lib for a later non invasive current sensor.
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‎libraries/EmonLib/EmonLib.cpp

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/*
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Emon.cpp - Library for openenergymonitor
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Created by Trystan Lea, April 27 2010
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GNU GPL
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modified to use up to 12 bits ADC resolution (ex. Arduino Due)
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by [email protected] 26.12.2013
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*/
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//#include "WProgram.h" un-comment for use on older versions of Arduino IDE
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#include "EmonLib.h"
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#if defined(ARDUINO) && ARDUINO >= 100
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#include "Arduino.h"
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#else
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#include "WProgram.h"
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#endif
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//--------------------------------------------------------------------------------------
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// Sets the pins to be used for voltage and current sensors
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//--------------------------------------------------------------------------------------
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void EnergyMonitor::voltage(int _inPinV, double _VCAL, double _PHASECAL)
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{
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inPinV = _inPinV;
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VCAL = _VCAL;
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PHASECAL = _PHASECAL;
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}
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void EnergyMonitor::current(int _inPinI, double _ICAL)
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{
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inPinI = _inPinI;
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ICAL = _ICAL;
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}
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//--------------------------------------------------------------------------------------
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// Sets the pins to be used for voltage and current sensors based on emontx pin map
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//--------------------------------------------------------------------------------------
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void EnergyMonitor::voltageTX(double _VCAL, double _PHASECAL)
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{
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inPinV = 2;
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VCAL = _VCAL;
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PHASECAL = _PHASECAL;
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}
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void EnergyMonitor::currentTX(int _channel, double _ICAL)
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{
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if (_channel == 1) inPinI = 3;
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if (_channel == 2) inPinI = 0;
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if (_channel == 3) inPinI = 1;
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ICAL = _ICAL;
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}
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//--------------------------------------------------------------------------------------
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// emon_calc procedure
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// Calculates realPower,apparentPower,powerFactor,Vrms,Irms,kwh increment
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// From a sample window of the mains AC voltage and current.
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// The Sample window length is defined by the number of half wavelengths or crossings we choose to measure.
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//--------------------------------------------------------------------------------------
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void EnergyMonitor::calcVI(int crossings, int timeout)
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{
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#if defined emonTxV3
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int SUPPLYVOLTAGE=3300;
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#else
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int SUPPLYVOLTAGE = readVcc();
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#endif
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int crossCount = 0; //Used to measure number of times threshold is crossed.
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int numberOfSamples = 0; //This is now incremented
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//-------------------------------------------------------------------------------------------------------------------------
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// 1) Waits for the waveform to be close to 'zero' (500 adc) part in sin curve.
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//-------------------------------------------------------------------------------------------------------------------------
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boolean st=false; //an indicator to exit the while loop
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unsigned long start = millis(); //millis()-start makes sure it doesnt get stuck in the loop if there is an error.
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while(st==false) //the while loop...
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{
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startV = analogRead(inPinV); //using the voltage waveform
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if ((startV < (ADC_COUNTS/2+50)) && (startV > (ADC_COUNTS/2-50))) st=true; //check its within range
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if ((millis()-start)>timeout) st = true;
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}
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//-------------------------------------------------------------------------------------------------------------------------
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// 2) Main measurment loop
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//-------------------------------------------------------------------------------------------------------------------------
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start = millis();
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while ((crossCount < crossings) && ((millis()-start)<timeout))
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{
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numberOfSamples++; //Count number of times looped.
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lastSampleV=sampleV; //Used for digital high pass filter
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lastSampleI=sampleI; //Used for digital high pass filter
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lastFilteredV = filteredV; //Used for offset removal
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lastFilteredI = filteredI; //Used for offset removal
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//-----------------------------------------------------------------------------
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// A) Read in raw voltage and current samples
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//-----------------------------------------------------------------------------
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sampleV = analogRead(inPinV); //Read in raw voltage signal
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sampleI = analogRead(inPinI); //Read in raw current signal
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//-----------------------------------------------------------------------------
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// B) Apply digital high pass filters to remove 2.5V DC offset (centered on 0V).
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//-----------------------------------------------------------------------------
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filteredV = 0.996*(lastFilteredV+(sampleV-lastSampleV));
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filteredI = 0.996*(lastFilteredI+(sampleI-lastSampleI));
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//-----------------------------------------------------------------------------
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// C) Root-mean-square method voltage
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//-----------------------------------------------------------------------------
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sqV= filteredV * filteredV; //1) square voltage values
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sumV += sqV; //2) sum
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//-----------------------------------------------------------------------------
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// D) Root-mean-square method current
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//-----------------------------------------------------------------------------
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sqI = filteredI * filteredI; //1) square current values
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sumI += sqI; //2) sum
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//-----------------------------------------------------------------------------
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// E) Phase calibration
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//-----------------------------------------------------------------------------
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phaseShiftedV = lastFilteredV + PHASECAL * (filteredV - lastFilteredV);
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//-----------------------------------------------------------------------------
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// F) Instantaneous power calc
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//-----------------------------------------------------------------------------
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instP = phaseShiftedV * filteredI; //Instantaneous Power
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sumP +=instP; //Sum
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//-----------------------------------------------------------------------------
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// G) Find the number of times the voltage has crossed the initial voltage
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// - every 2 crosses we will have sampled 1 wavelength
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// - so this method allows us to sample an integer number of half wavelengths which increases accuracy
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//-----------------------------------------------------------------------------
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lastVCross = checkVCross;
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if (sampleV > startV) checkVCross = true;
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else checkVCross = false;
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if (numberOfSamples==1) lastVCross = checkVCross;
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if (lastVCross != checkVCross) crossCount++;
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}
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//-------------------------------------------------------------------------------------------------------------------------
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// 3) Post loop calculations
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//-------------------------------------------------------------------------------------------------------------------------
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//Calculation of the root of the mean of the voltage and current squared (rms)
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//Calibration coeficients applied.
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double V_RATIO = VCAL *((SUPPLYVOLTAGE/1000.0) / (ADC_COUNTS));
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Vrms = V_RATIO * sqrt(sumV / numberOfSamples);
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double I_RATIO = ICAL *((SUPPLYVOLTAGE/1000.0) / (ADC_COUNTS));
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Irms = I_RATIO * sqrt(sumI / numberOfSamples);
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//Calculation power values
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realPower = V_RATIO * I_RATIO * sumP / numberOfSamples;
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apparentPower = Vrms * Irms;
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powerFactor=realPower / apparentPower;
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//Reset accumulators
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sumV = 0;
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sumI = 0;
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sumP = 0;
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//--------------------------------------------------------------------------------------
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}
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//--------------------------------------------------------------------------------------
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double EnergyMonitor::calcIrms(int NUMBER_OF_SAMPLES)
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{
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#if defined emonTxV3
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int SUPPLYVOLTAGE=3300;
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#else
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int SUPPLYVOLTAGE = readVcc();
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#endif
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for (int n = 0; n < NUMBER_OF_SAMPLES; n++)
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{
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lastSampleI = sampleI;
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sampleI = analogRead(inPinI);
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lastFilteredI = filteredI;
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filteredI = 0.996*(lastFilteredI+sampleI-lastSampleI);
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// Root-mean-square method current
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// 1) square current values
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sqI = filteredI * filteredI;
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// 2) sum
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sumI += sqI;
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}
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double I_RATIO = ICAL *((SUPPLYVOLTAGE/1000.0) / (ADC_COUNTS));
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Irms = I_RATIO * sqrt(sumI / NUMBER_OF_SAMPLES);
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//Reset accumulators
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sumI = 0;
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//--------------------------------------------------------------------------------------
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return Irms;
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}
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void EnergyMonitor::serialprint()
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{
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Serial.print(realPower);
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Serial.print(' ');
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Serial.print(apparentPower);
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Serial.print(' ');
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Serial.print(Vrms);
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Serial.print(' ');
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Serial.print(Irms);
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Serial.print(' ');
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Serial.print(powerFactor);
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Serial.println(' ');
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delay(100);
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}
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//thanks to http://hacking.majenko.co.uk/making-accurate-adc-readings-on-arduino
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//and Jérôme who alerted us to http://provideyourown.com/2012/secret-arduino-voltmeter-measure-battery-voltage/
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long EnergyMonitor::readVcc() {
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long result;
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//not used on emonTx V3 - as Vcc is always 3.3V - eliminates bandgap error and need for calibration http://harizanov.com/2013/09/thoughts-on-avr-adc-accuracy/
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#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega328__) || defined (__AVR_ATmega328P__)
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ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
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#elif defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__) || defined(__AVR_AT90USB1286__)
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ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
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ADCSRB &= ~_BV(MUX5); // Without this the function always returns -1 on the ATmega2560 http://openenergymonitor.org/emon/node/2253#comment-11432
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#elif defined (__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
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ADMUX = _BV(MUX5) | _BV(MUX0);
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#elif defined (__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
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ADMUX = _BV(MUX3) | _BV(MUX2);
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#endif
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#if defined(__AVR__)
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delay(2); // Wait for Vref to settle
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ADCSRA |= _BV(ADSC); // Convert
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while (bit_is_set(ADCSRA,ADSC));
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result = ADCL;
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result |= ADCH<<8;
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result = 1126400L / result; //1100mV*1024 ADC steps http://openenergymonitor.org/emon/node/1186
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return result;
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#elif defined(__arm__)
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return (3300); //Arduino Due
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#else
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return (3300); //Guess that other un-supported architectures will be running a 3.3V!
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#endif
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}
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‎libraries/EmonLib/EmonLib.h

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/*
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Emon.h - Library for openenergymonitor
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Created by Trystan Lea, April 27 2010
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GNU GPL
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modified to use up to 12 bits ADC resolution (ex. Arduino Due)
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by [email protected] 26.12.2013
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*/
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#ifndef EmonLib_h
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#define EmonLib_h
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#if defined(ARDUINO) && ARDUINO >= 100
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#include "Arduino.h"
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#else
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#include "WProgram.h"
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#endif
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// to enable 12-bit ADC resolution on Arduino Due,
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// include the following line in main sketch inside setup() function:
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// analogReadResolution(ADC_BITS);
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// otherwise will default to 10 bits, as in regular Arduino-based boards.
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#if defined(__arm__)
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#define ADC_BITS 12
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#else
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#define ADC_BITS 10
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#endif
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#define ADC_COUNTS (1<<ADC_BITS)
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class EnergyMonitor
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{
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public:
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void voltage(int _inPinV, double _VCAL, double _PHASECAL);
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void current(int _inPinI, double _ICAL);
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void voltageTX(double _VCAL, double _PHASECAL);
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void currentTX(int _channel, double _ICAL);
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void calcVI(int crossings, int timeout);
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double calcIrms(int NUMBER_OF_SAMPLES);
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void serialprint();
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long readVcc();
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//Useful value variables
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double realPower,
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apparentPower,
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powerFactor,
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Vrms,
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Irms;
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private:
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//Set Voltage and current input pins
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int inPinV;
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int inPinI;
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//Calibration coeficients
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//These need to be set in order to obtain accurate results
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double VCAL;
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double ICAL;
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double PHASECAL;
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//--------------------------------------------------------------------------------------
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// Variable declaration for emon_calc procedure
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//--------------------------------------------------------------------------------------
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int lastSampleV,sampleV; //sample_ holds the raw analog read value, lastSample_ holds the last sample
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int lastSampleI,sampleI;
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double lastFilteredV,filteredV; //Filtered_ is the raw analog value minus the DC offset
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double lastFilteredI, filteredI;
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double phaseShiftedV; //Holds the calibrated phase shifted voltage.
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double sqV,sumV,sqI,sumI,instP,sumP; //sq = squared, sum = Sum, inst = instantaneous
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int startV; //Instantaneous voltage at start of sample window.
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boolean lastVCross, checkVCross; //Used to measure number of times threshold is crossed.
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int crossCount; // ''
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};
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#endif

‎libraries/EmonLib/Readme.txt

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_ _ _
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| | (_) |
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___ _ __ ___ ___ _ __ | | _| |__
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/ _ \ '_ ` _ \ / _ \| '_ \| | | | '_ \
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| __/ | | | | | (_) | | | | |____| | |_) |
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\___|_| |_| |_|\___/|_| |_|______|_|_.__/
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Arduino Energy Monitoring Library - compatible with Arduino 1.0
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*****************************************************************
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Designed for use with emonTx: http://openenergymonitor.org/emon/Modules
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Download to Arduino IDE 'libraries' folder. Restart of IDE required.
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Git Clone and Git Pull can be easily used to keep the library up-to-date and manage changes.
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JeeLabs has done a good post on the topic: http://jeelabs.org/2011/12/29/out-with-the-old-in-with-the-new/
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Update: 5th January 2014: Support Added for Arduino Due (ARM Cortex-M3, 12-bit ADC) by icboredman.
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To enable this feature on Arduino Due, add the following statement to setup() function in main sketch:
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analogReadResolution(ADC_BITS); This will set ADC_BITS to 12 (Arduino Due), EmonLib will otherwise default to 10 analogReadResolution(ADC_BITS);.
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See blog post on using Arduino Due as energy monitor: http://boredomprojects.net/index.php/projects/home-energy-monitor
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‎libraries/EmonLib/examples/current_only/current_only.ino

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// EmonLibrary examples openenergymonitor.org, Licence GNU GPL V3
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#include "EmonLib.h" // Include Emon Library
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EnergyMonitor emon1; // Create an instance
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void setup()
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{
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Serial.begin(9600);
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emon1.current(1, 111.1); // Current: input pin, calibration.
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}
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void loop()
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{
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double Irms = emon1.calcIrms(1480); // Calculate Irms only
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Serial.print(Irms*230.0); // Apparent power
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Serial.print(" ");
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Serial.println(Irms); // Irms
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}

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