MQSensorsLib/src/MQUnifiedsensor.cpp
2020-04-20 19:40:27 -05:00

206 lines
8.3 KiB
C++

#include "MQUnifiedsensor.h"
MQUnifiedsensor::MQUnifiedsensor(String Placa, float Voltage_Resolution, int ADC_Bit_Resolution, int pin, String type) {
this->_pin = pin;
Placa.toCharArray(this->_placa, 20);
type.toCharArray(this->_type, 6);
//this->_type = type; //MQ-2, MQ-3 ... MQ-309A
//this->_placa = Placa;
this-> _VOLT_RESOLUTION = Voltage_Resolution;
this-> _ADC_Bit_Resolution = ADC_Bit_Resolution;
}
void MQUnifiedsensor::init()
{
pinMode(_pin, INPUT);
}
void MQUnifiedsensor::setA(float a) {
this->_a = a;
}
void MQUnifiedsensor::setB(float b) {
this->_b = b;
}
void MQUnifiedsensor::setR0(float R0) {
this->_R0 = R0;
}
void MQUnifiedsensor::setRL(float RL) {
this->_RL = RL;
}
void MQUnifiedsensor::setADC(int value)
{
this-> _sensor_volt = (value) * _VOLT_RESOLUTION / ((pow(2, _ADC_Bit_Resolution)) - 1);
this-> _adc = value;
}
void MQUnifiedsensor::setVoltResolution(float voltage_resolution)
{
_VOLT_RESOLUTION = voltage_resolution;
}
void MQUnifiedsensor::setRegressionMethod(int regressionMethod)
{
//this->_regressionMethod = regressionMethod;
this->_regressionMethod = regressionMethod;
}
float MQUnifiedsensor::getR0() {
return _R0;
}
float MQUnifiedsensor::getRL() {
return _RL;
}
float MQUnifiedsensor::getVoltResolution()
{
return _VOLT_RESOLUTION;
}
String MQUnifiedsensor::getRegressionMethod()
{
if(_regressionMethod == 1) return "Exponential";
else return "Linear";
}
float MQUnifiedsensor::getA() {
return _a;
}
float MQUnifiedsensor::getB() {
return _b;
}
void MQUnifiedsensor::serialDebug(bool onSetup)
{
if(onSetup)
{
Serial.println();
Serial.println("************************************************************************************************************************************************");
Serial.println("MQ sensor reading library for arduino");
Serial.println("Note: remember that all the parameters below can be modified during the program execution with the methods:");
Serial.println("setR0, setRL, setA, setB where you will have to send as parameter the new value, example: mySensor.setR0(20); //R0 = 20KΩ");
Serial.println("Authors: Miguel A. Califa U - Yersson R. Carrillo A - Ghiordy F. Contreras C");
Serial.println("Contributors: Andres A. Martinez - Juan A. Rodríguez - Mario A. Rodríguez O ");
Serial.print("Sensor: "); Serial.println(_type);
Serial.print("Supply voltage: "); Serial.print(_VOLT_RESOLUTION); Serial.println(" VDC");
Serial.print("ADC Resolution: "); Serial.print(_ADC_Bit_Resolution); Serial.println(" Bits");
Serial.print("R0: "); Serial.print(_R0); Serial.println("");
Serial.print("RL: "); Serial.print(_RL); Serial.println("");
Serial.print("Model: "); if(_regressionMethod == 1) Serial.println("Exponential"); else Serial.println("Linear");
Serial.print(_type); Serial.print(" -> a: "); Serial.print(_a); Serial.print(" | b: "); Serial.println(_b);
Serial.print("Development board: "); Serial.println(_placa);
}
else
{
if(!_firstFlag)
{
Serial.print("| ********************************************************************"); Serial.print(_type); Serial.println("*********************************************************************|");
Serial.println("|ADC_In | Equation_V_ADC | Voltage_ADC | Equation_RS | Resistance_RS | EQ_Ratio | Ratio (RS/R0) | Equation_PPM | PPM |");
_firstFlag = true; //Headers are printed
}
else
{
Serial.print("|"); Serial.print(_adc); Serial.print("| v = ADC*"); Serial.print(_VOLT_RESOLUTION); Serial.print("/"); Serial.print((pow(2, _ADC_Bit_Resolution)) - 1); Serial.print(" | "); Serial.print(_sensor_volt);
Serial.print(" | RS = ((" ); Serial.print(_VOLT_RESOLUTION ); Serial.print("*RL)/Voltage) - RL| "); Serial.print(_RS_Calc); Serial.print(" | Ratio = RS/R0| ");
Serial.print(_ratio); Serial.print( " | ");
if(_regressionMethod == 1) Serial.print("ratio*a + b");
else Serial.print("pow(10, (log10(ratio)-b)/a)");
Serial.print(" | "); Serial.print(_PPM); Serial.println(" |");
}
}
}
void MQUnifiedsensor::update()
{
_sensor_volt = this->getVoltage();
}
float MQUnifiedsensor::validateEcuation(float ratioInput)
{
//Serial.print("Ratio input: "); Serial.println(ratioInput);
//Serial.print("a: "); Serial.println(_a);
//Serial.print("b: "); Serial.println(_b);
//Usage of this function: Unit test on ALgorithmTester example;
if(_regressionMethod == 1) _PPM= _a*pow(ratioInput, _b);
else
{
// https://jayconsystems.com/blog/understanding-a-gas-sensor
double ppm_log = (log10(ratioInput)-_b)/_a; //Get ppm value in linear scale according to the the ratio value
_PPM = pow(10, ppm_log); //Convert ppm value to log scale
}
//Serial.println("Regression Method: "); Serial.println(_regressionMethod);
//Serial.println("Result: "); Serial.println(_PPM);
return _PPM;
}
float MQUnifiedsensor::readSensor()
{
//More explained in: https://jayconsystems.com/blog/understanding-a-gas-sensor
_RS_Calc = ((_VOLT_RESOLUTION*_RL)/_sensor_volt)-_RL; //Get value of RS in a gas
if(_RS_Calc < 0) _RS_Calc = 0; //No negative values accepted.
_ratio = _RS_Calc / this->_R0; // Get ratio RS_gas/RS_air
if(_ratio <= 0) _ratio = 0; //No negative values accepted or upper datasheet recomendation.
if(_regressionMethod == 1) _PPM= _a*pow(_ratio, _b); // <- Source excel analisis https://github.com/miguel5612/MQSensorsLib_Docs/tree/master/Internal_design_documents
else
{
// https://jayconsystems.com/blog/understanding-a-gas-sensor <- Source of linear ecuation
double ppm_log = (log10(_ratio)-_b)/_a; //Get ppm value in linear scale according to the the ratio value
_PPM = pow(10, ppm_log); //Convert ppm value to log scale
}
if(_PPM < 0) _PPM = 0; //No negative values accepted or upper datasheet recomendation.
//if(_PPM > 10000) _PPM = 99999999; //No negative values accepted or upper datasheet recomendation.
return _PPM;
}
float MQUnifiedsensor::readSensorR0Rs()
{
//More explained in: https://jayconsystems.com/blog/understanding-a-gas-sensor
_RS_Calc = ((_VOLT_RESOLUTION*_RL)/_sensor_volt)-_RL; //Get value of RS in a gas
if(_RS_Calc < 0) _RS_Calc = 0; //No negative values accepted.
_ratio = this->_R0/_RS_Calc; // Get ratio RS_air/RS_gas <- INVERTED for MQ-131 issue 28 https://github.com/miguel5612/MQSensorsLib/issues/28
if(_ratio <= 0) _ratio = 0; //No negative values accepted or upper datasheet recomendation.
if(_regressionMethod == 1) _PPM= _a*pow(_ratio, _b); // <- Source excel analisis https://github.com/miguel5612/MQSensorsLib_Docs/tree/master/Internal_design_documents
else
{
// https://jayconsystems.com/blog/understanding-a-gas-sensor <- Source of linear ecuation
double ppm_log = (log10(_ratio)-_b)/_a; //Get ppm value in linear scale according to the the ratio value
_PPM = pow(10, ppm_log); //Convert ppm value to log scale
}
if(_PPM < 0) _PPM = 0; //No negative values accepted or upper datasheet recomendation.
//if(_PPM > 10000) _PPM = 99999999; //No negative values accepted or upper datasheet recomendation.
return _PPM;
}
float MQUnifiedsensor::calibrate(float ratioInCleanAir) {
//More explained in: https://jayconsystems.com/blog/understanding-a-gas-sensor
/*
V = I x R
VRL = [VC / (RS + RL)] x RL
VRL = (VC x RL) / (RS + RL)
Así que ahora resolvemos para RS:
VRL x (RS + RL) = VC x RL
(VRL x RS) + (VRL x RL) = VC x RL
(VRL x RS) = (VC x RL) - (VRL x RL)
RS = [(VC x RL) - (VRL x RL)] / VRL
RS = [(VC x RL) / VRL] - RL
*/
float RS_air; //Define variable for sensor resistance
float R0; //Define variable for R0
RS_air = ((_VOLT_RESOLUTION*_RL)/_sensor_volt)-_RL; //Calculate RS in fresh air
if(RS_air < 0) RS_air = 0; //No negative values accepted.
R0 = RS_air/ratioInCleanAir; //Calculate R0
if(R0 < 0) R0 = 0; //No negative values accepted.
return R0;
}
float MQUnifiedsensor::getVoltage(int read) {
float voltage;
if(read)
{
float avg = 0.0;
for (int i = 0; i < retries; i ++) {
_adc = analogRead(this->_pin);
avg += _adc;
delay(retry_interval);
}
voltage = (avg/ retries) * _VOLT_RESOLUTION / ((pow(2, _ADC_Bit_Resolution)) - 1);
}
else
{
voltage = _sensor_volt;
}
return voltage;
}
float MQUnifiedsensor::stringTofloat(String & str)
{
return atof( str.c_str() );
}