GravityEc.cpp

/*********************************************************************
* GravityEc.cpp
*
* Copyright (C)    2017   [DFRobot](http://www.dfrobot.com),
* GitHub Link :https://github.com/DFRobot/watermonitor
* This Library is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Description:Monitoring water quality parameters Conductivity
*
* Product Links：http://www.dfrobot.com.cn/goods-882.html
*
* Sensor driver pin：A1 (ecSensorPin(A1))
*
* author  :  Jason(jason.ling@dfrobot.com)
* version :  V1.0
* date    :  2017-04-17
**********************************************************************/

#include "GravityEc.h"
#include "Arduino.h"



GravityEc::GravityEc(ISensor* temp) :ecSensorPin(A1), ECcurrent(0), index(0), AnalogAverage(0),
AnalogValueTotal(0), averageVoltage(0), AnalogSampleTime(0), printTime(0),sum(0),
tempSampleTime(0), AnalogSampleInterval(25),printInterval(700)
{
	this->ecTemperature = temp;
}


GravityEc::~GravityEc()
{
}


//********************************************************************************************
// function name: setup ()
// Function Description: Initializes the sensor
//********************************************************************************************
void GravityEc::setup()
{
	pinMode(ecSensorPin, INPUT);
	for (byte thisReading = 0; thisReading < numReadings; thisReading++)
		readings[thisReading] = 0;
}


//********************************************************************************************
// function name: update ()
// Function Description: Update the sensor value
//********************************************************************************************
void GravityEc::update()
{
	calculateAnalogAverage();
	calculateEc();
}


//********************************************************************************************
// function name: getValue ()
// Function Description: Returns the sensor data
//********************************************************************************************
double GravityEc::getValue()
{
	return ECcurrent;
}


//********************************************************************************************
// function name: calculateAnalogAverage ()
// Function Description: Calculates the average voltage
//********************************************************************************************
void GravityEc::calculateAnalogAverage()
{
	if (millis() - AnalogSampleTime >= AnalogSampleInterval)
	{
		AnalogSampleTime = millis();
		readings[index++] = analogRead(ecSensorPin);
		if (index == numReadings)
		{
			index = 0;
			for (int i = 0; i < numReadings; i++)
				this->sum += readings[i];
			AnalogAverage = this->sum / numReadings;
			this->sum = 0;
		}
	}
}


//********************************************************************************************
// function name: calculateAnalogAverage ()
// Function Description: Calculate the conductivity
//********************************************************************************************
void GravityEc::calculateEc()
{
	if (millis() - printTime >= printInterval)
	{
		printTime = millis();
		averageVoltage = AnalogAverage*5000.0 / 1024.0;
		double TempCoefficient = 1.0 + 0.0185*(this->ecTemperature->getValue() - 25.0);    //temperature compensation formula: fFinalResult(25^C) = fFinalResult(current)/(1.0+0.0185*(fTP-25.0));

		double CoefficientVolatge = (double)averageVoltage / TempCoefficient;

		if (CoefficientVolatge < 150) {
			ECcurrent = 0;
			return;
		}
		else if (CoefficientVolatge > 3300)
		{
			ECcurrent = 20;
			return;
		}
		else
		{
			if (CoefficientVolatge <= 448)
				ECcurrent = 6.84*CoefficientVolatge - 64.32;   //1ms/cm<EC<=3ms/cm
			else if (CoefficientVolatge <= 1457)
				ECcurrent = 6.98*CoefficientVolatge - 127;   //3ms/cm<EC<=10ms/cm
			else
				ECcurrent = 5.3*CoefficientVolatge + 2278;                           //10ms/cm<EC<20ms/cm
			ECcurrent /= 1000;    //convert us/cm to ms/cm
		}
	}
}