Changed variable types

examples/Calibration/Calibration.ino

@@ -19,7 +19,7 @@
 //Definitions
 #define placa "Arduino UNO"
 #define Voltage_Resolution 5
-#define pin A0 //Analog input 0 of your arduino
+#define pin A2 //Analog input 0 of your arduino
 #define type "MQ-2" //MQ2
 #define ADC_Bit_Resolution 10 // For arduino UNO/MEGA/NANO
 
@@ -40,7 +40,7 @@
 
 //Declare Sensor
 
-MQUnifiedsensor MQ2(placa, Voltage_Resolution, ADC_Bit_Resolution, pin2, type);
+MQUnifiedsensor MQ2(placa, Voltage_Resolution, ADC_Bit_Resolution, pin, type);
 unsigned long contador = 0;
 
 void setup() {
@@ -51,16 +51,18 @@ void setup() {
   //init the sensor
   MQ2.init(); 
   //Print in serial monitor
-  Serial.print("MQ2 - Calibracion");
+  Serial.println("MQ2 - Calibracion");
-  Serial.print("Note - Make sure you are in a clean room and the sensor has pre-heated almost 4 hours");
+  Serial.println("Note - Make sure you are in a clean room and the sensor has pre-heated almost 4 hours");
-  Serial.print("Autonumeric, lecture");
+  Serial.println("Autonumeric | lecture (R0)");
 }
 
 void loop() {
+  MQ2.update();
   //Read the sensor and print in serial port
-  int lecture =  MQ2.calibrate(RatioMQ2CleanAir);
+  float lecture =  MQ2.calibrate(RatioMQ2CleanAir);
   //Print in serial monitor
-  Serial.print(String(contador) + ",");
+  Serial.print(contador);
+  Serial.print(" | ");
   Serial.println(lecture);
   //Increment counter
   contador++;

examples/MQ-131/MQ-131.ino

@@ -57,7 +57,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ131.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-135/MQ-135.ino

@@ -60,7 +60,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ135.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-2/MQ-2.ino

@@ -56,7 +56,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ2.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-3/MQ-3.ino

@@ -59,7 +59,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ3.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-303A/MQ303.ino

@@ -57,7 +57,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ303.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-309A/MQ-309.ino

@@ -58,7 +58,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ309.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-4/MQ-4.ino

@@ -59,7 +59,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ4.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-5/MQ-5.ino

@@ -58,7 +58,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ5.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-6/MQ-6.ino

@@ -58,7 +58,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ6.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-7/MQ-7.ino

@@ -59,7 +59,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ7.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-8/MQ-8.ino

@@ -59,7 +59,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ8.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-9/MQ-9.ino

@@ -57,7 +57,7 @@ void setup() {
   // This routine not need to execute to every restart, you can load your R0 if you know the value
   // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
   Serial.print("Calibrating please wait.");
-  int calcR0 = 0;
+  float calcR0 = 0;
   for(int i = 0; i<=10; i ++)
   {
     MQ9.update(); // Update data, the arduino will be read the voltage on the analog pin

examples/MQ-Board-Calibration/MQ-Board-Calibration.ino

@@ -1,207 +0,0 @@
-/*
-  MQUnifiedsensor Library - calibrating an MQ2 to MQ9
-
-  Demonstrates the use a MQ2 sensor.
-  Library originally added 01 may 2019
-  by Miguel A Califa, Yersson Carrillo, Ghiordy Contreras, Mario Rodriguez
- 
-  Added example
-  modified 27 May 2019
-  by Miguel Califa 
-
-  Added LCD
-  modified 26 May 2019
-  by Miguel Califa 
-
-  Changed sample frecuency
-  modified 28 May 2019
-  by Ghiordy contreras, Miguel Califa 
-
-  Added voltaje to log
-  modified 29 May 2019
-  by Miguel Califa 
-  
- This example code is in the public domain.
-
-*/
-
-//Include the library
-#include <MQUnifiedsensor.h>
-//And lcd library
-#include <Wire.h> 
-#include <LiquidCrystal_I2C.h>
-
-// Set the LCD address to 0x27 for a 16 chars and 2 line display
-LiquidCrystal_I2C lcd(0x27, 16, 2);
-
-//Definitions
-#define placa "Arduino Mega 2560"
-#define Voltage_Resolution 5
-#define type "MQ-Board"
-#define ADC_Bit_Resolution 10 // For arduino UNO/MEGA/NANO
-#define pin2 A2 //Analog input 2 of your arduino
-#define pin3 A3 //Analog input 3 of your arduino
-#define pin4 A4 //Analog input 4 of your arduino
-#define pin5 A5 //Analog input 5 of your arduino
-#define pin6 A6 //Analog input 6 of your arduino
-#define pin7 A7 //Analog input 7 of your arduino
-#define pin8 A8 //Analog input 8 of your arduino
-#define pin9 A9 //Analog input 9 of your arduino
-
-#define RatioMQ2CleanAir 9.83 //RS / R0 = 9.83 ppm 
-#define RatioMQ3CleanAir 60   //RS / R0 = 60 ppm 
-#define RatioMQ4CleanAir 4.4  //RS / R0 = 4.4 ppm 
-#define RatioMQ5CleanAir 6.5  //RS / R0 = 6.5 ppm 
-#define RatioMQ6CleanAir 10   //RS / R0 = 10 ppm 
-#define RatioMQ7CleanAir 27.5 //RS / R0 = 27.5 ppm  
-#define RatioMQ8CleanAir 70   //RS / R0 = 70 ppm   
-#define RatioMQ9CleanAir 9.6  //RS / R0 = 9.6 ppm    
-#define RatioMQ131CleanAir 15 //RS / R0 = 15 ppm
-#define RatioMQ135CleanAir 3.6//RS / R0 = 3.6 ppm     
-#define RatioMQ303CleanAir 1  //RS / R0 = 1 ppm    
-#define RatioMQ309CleanAir 11 //RS / R0 = 11 ppm    
-
-
-#define timeDelay 500
-//Declare Sensor
-
-MQUnifiedsensor MQ2(placa, Voltage_Resolution, ADC_Bit_Resolution, pin2, type);
-MQUnifiedsensor MQ3(placa, Voltage_Resolution, ADC_Bit_Resolution, pin3, type);
-MQUnifiedsensor MQ4(placa, Voltage_Resolution, ADC_Bit_Resolution, pin4, type);
-MQUnifiedsensor MQ5(placa, Voltage_Resolution, ADC_Bit_Resolution, pin5, type);
-MQUnifiedsensor MQ6(placa, Voltage_Resolution, ADC_Bit_Resolution, pin6, type);
-MQUnifiedsensor MQ7(placa, Voltage_Resolution, ADC_Bit_Resolution, pin7, type);
-MQUnifiedsensor MQ8(placa, Voltage_Resolution, ADC_Bit_Resolution, pin8, type);
-MQUnifiedsensor MQ9(placa, Voltage_Resolution, ADC_Bit_Resolution, pin9, type);
-
-unsigned long contador = 0;
-unsigned long time = millis();
-
-void setup() {
-  //Init serial port
-  Serial.begin(9600);
-  // initialize the LCD
-  lcd.begin();
-  // Turn on the blacklight and print a message.
-  lcd.backlight();
-  //Welcome message
-  lcd.clear();
-  lcd.setCursor(0,0);
-  lcd.print("MQ2 to MQ9");
-  lcd.setCursor(0,1);
-  lcd.print("   Calibrating");
-  //init the sensor
-  
-  MQ2.init();
-  MQ2.setRegressionMethod(1); //_PPM =  a*ratio^b
-  MQ2.setA(574.25); MQ2.setB(-2.222); // Configurate the ecuation values to get LPG concentration
-  MQ2.setR0(9.659574468);
-
-  MQ3.init(); 
-  MQ3.setRegressionMethod(1); //_PPM =  a*ratio^b
-  MQ3.setA(4.8387); MQ3.setB(-2.68); // Configurate the ecuation values to get Benzene concentration
-  MQ3.setR0(3.86018237);
-
-  MQ4.init(); 
-  MQ4.setRegressionMethod(1); //_PPM =  a*ratio^b
-  MQ4.setA(1012.7); MQ4.setB(-2.786); // Configurate the ecuation values to get CH4 concentration
-  MQ4.setR0(3.86018237);
-
-  MQ5.init(); 
-  MQ5.setRegressionMethod(1); //_PPM =  a*ratio^b
-  MQ5.setA(1163.8); MQ5.setB(-3.874); // Configurate the ecuation values to get H2 concentration
-  MQ5.setR0(71.100304);
-  
-  MQ6.init(); 
-  MQ6.setRegressionMethod(1); //_PPM =  a*ratio^b
-  MQ6.setA(2127.2); MQ6.setB(-2.526); // Configurate the ecuation values to get CH4 concentration
-  MQ6.setR0(13.4285714);
-  
-  MQ7.init(); 
-  MQ7.setRegressionMethod(1); //_PPM =  a*ratio^b
-  MQ7.setA(99.042); MQ7.setB(-1.518); // Configurate the ecuation values to get CO concentration
-  MQ7.setR0(4);
-  
-  MQ8.init(); 
-  MQ8.setRegressionMethod(1); //_PPM =  a*ratio^b
-  MQ8.setA(976.97); MQ8.setB(-0.688); // Configurate the ecuation values to get H2 concentration
-  MQ8.setR0(1);
-  
-  MQ9.init(); 
-  MQ9.setRegressionMethod(1); //_PPM =  a*ratio^b
-  MQ9.setA(1000.5); MQ9.setB(-2.186); // Configurate the ecuation values to get LPG concentration
-  MQ9.setR0(9.42857143);
-
-  //Print in serial monitor
-  Serial.println("MQ2 to MQ9 - Calibracion");
-  Serial.println("Note - Make sure you are in a clean room and the sensor has pre-heated almost 4 hours");
-  Serial.println("Note - All values are in KOhms");
-  Serial.println("Autonumeric, MQ2(R0), MQ3(R0), MQ4(R0), MQ5(R0), MQ6(R0), MQ7(R0), MQ8(R0), MQ9(R0), v2(VDC), v3(VDC), v4(VDC), v5(VDC), v6(VDC), v7(VDC), v8(VDC), v9(VDC)");
-  //Wait one second to continue
-  delay(timeDelay/10);
-}
-
-void loop() {
-  //Update the voltage lectures
-  MQ2.update();
-  MQ3.update();
-  MQ4.update();
-  MQ5.update();
-  MQ6.update();
-  MQ7.update();
-  MQ8.update();
-  MQ9.update();
-  
-  //Read the sensor
-  float lecture2 =  MQ2.calibrate(RatioMQ2CleanAir);
-  float lecture3 =  MQ3.calibrate(RatioMQ3CleanAir);
-  float lecture4 =  MQ4.calibrate(RatioMQ4CleanAir);
-  float lecture5 =  MQ5.calibrate(RatioMQ5CleanAir);
-  float lecture6 =  MQ6.calibrate(RatioMQ6CleanAir);
-  float lecture7 =  MQ7.calibrate(RatioMQ7CleanAir);
-  float lecture8 =  MQ8.calibrate(RatioMQ8CleanAir);
-  float lecture9 =  MQ9.calibrate(RatioMQ9CleanAir);
-
-    //Read voltage the sensor
-  float v2 =  MQ2.getVoltage(false);
-  float v3 =  MQ3.getVoltage(false);
-  float v4 =  MQ4.getVoltage(false);
-  float v5 =  MQ5.getVoltage(false);
-  float v6 =  MQ6.getVoltage(false);
-  float v7 =  MQ7.getVoltage(false);
-  float v8 =  MQ8.getVoltage(false);
-  float v9 =  MQ9.getVoltage(false);
-
-  
-  //Print in serial monitor
-  Serial.print(contador);Serial.print(",");
-  Serial.print(lecture2);Serial.print(",");
-  Serial.print(lecture3);Serial.print(",");
-  Serial.print(lecture4);Serial.print(",");
-  Serial.print(lecture5);Serial.print(",");
-  Serial.print(lecture6);Serial.print(",");
-  Serial.print(lecture7);Serial.print(",");
-  Serial.print(lecture8);Serial.print(",");
-  Serial.print(lecture9);Serial.print(",");
-  //Print voltages
-  Serial.print(v2);Serial.print(",");
-  Serial.print(v3);Serial.print(",");
-  Serial.print(v4);Serial.print(",");
-  Serial.print(v5);Serial.print(",");
-  Serial.print(v6);Serial.print(",");
-  Serial.print(v7);Serial.print(",");
-  Serial.print(v8);Serial.print(",");
-  Serial.println(v9);
-  
-
-  //Print in LCD
-  lcd.clear();
-  lcd.setCursor(0,0);
-  lcd.print("**CALIBRATING***");
-  lcd.setCursor(0,1);
-  lcd.print("Time: " + String((millis() - time)/60000) + "min");
-  //Increment counter
-  contador++;
-  //Wait to measure next sample
-  delay(timeDelay/4);
-}

examples/MQ-Board/MQ-Board.ino

@@ -29,7 +29,15 @@
 #define pin7 A7 //Analog input 7 of your arduino
 #define pin8 A8 //Analog input 8 of your arduino
 #define pin9 A9 //Analog input 9 of your arduino
-//#define calibration_button 13 //Pin to calibrate your sensor
+
+#define RatioMQ2CleanAir 9.83 //RS / R0 = 9.83 ppm 
+#define RatioMQ3CleanAir 60   //RS / R0 = 60 ppm 
+#define RatioMQ4CleanAir 4.4  //RS / R0 = 4.4 ppm 
+#define RatioMQ5CleanAir 6.5  //RS / R0 = 6.5 ppm 
+#define RatioMQ6CleanAir 10   //RS / R0 = 10 ppm 
+#define RatioMQ7CleanAir 27.5 //RS / R0 = 27.5 ppm  
+#define RatioMQ8CleanAir 70   //RS / R0 = 70 ppm   
+#define RatioMQ9CleanAir 9.6  //RS / R0 = 9.6 ppm  
 
 //Declare Sensor
 MQUnifiedsensor MQ2(placa, Voltage_Resolution, ADC_Bit_Resolution, pin2, type);
@@ -87,8 +95,75 @@ void setup() {
   MQ9.setRegressionMethod(1); //_PPM =  a*ratio^b
   MQ9.setA(1000.5); MQ9.setB(-2.186); // Configurate the ecuation values to get LPG concentration
   MQ9.setR0(9.42857143);
+
+   /*****************************  MQ CAlibration ********************************************/ 
+  // Explanation: 
+  // In this routine the sensor will measure the resistance of the sensor supposing before was pre-heated
+  // and now is on clean air (Calibration conditions), and it will setup R0 value.
+  // We recomend execute this routine only on setup or on the laboratory and save on the eeprom of your arduino
+  // This routine not need to execute to every restart, you can load your R0 if you know the value
+  // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
+  Serial.print("Calibrating please wait.");
+  float MQ2calcR0 = 0, 
+  MQ3calcR0 = 0,
+  MQ4calcR0 = 0,
+  MQ5calcR0 = 0,
+  MQ6calcR0 = 0,
+  MQ7calcR0 = 0,
+  MQ8calcR0 = 0,
+  MQ9calcR0 = 0;
+  for(int i = 0; i<=20; i ++)
+  {
+    //Update the voltage lectures
+    MQ2.update();
+    MQ3.update();
+    MQ4.update();
+    MQ5.update();
+    MQ6.update();
+    MQ7.update();
+    MQ8.update();
+    MQ9.update();
+
+    MQ2calcR0 += MQ2.calibrate(RatioMQ2CleanAir);
+    MQ3calcR0 += MQ2.calibrate(RatioMQ3CleanAir);
+    MQ4calcR0 += MQ2.calibrate(RatioMQ4CleanAir);
+    MQ5calcR0 += MQ2.calibrate(RatioMQ5CleanAir);
+    MQ6calcR0 += MQ2.calibrate(RatioMQ6CleanAir);
+    MQ7calcR0 += MQ2.calibrate(RatioMQ7CleanAir);
+    MQ8calcR0 += MQ2.calibrate(RatioMQ8CleanAir);
+    MQ9calcR0 += MQ2.calibrate(RatioMQ9CleanAir);
+
+    Serial.print(".");
+  }
+  MQ2.setR0(MQ2calcR0/20);
+  MQ3.setR0(MQ3calcR0/20);
+  MQ4.setR0(MQ4calcR0/20);
+  MQ5.setR0(MQ5calcR0/20);
+  MQ6.setR0(MQ6calcR0/20);
+  MQ7.setR0(MQ7calcR0/20);
+  MQ8.setR0(MQ8calcR0/20);
+  MQ9.setR0(MQ9calcR0/20);
+  Serial.println("  done!.");
+  
+  Serial.print("Valores de R0 para cada sensor (MQ2 - MQ9):");
+  Serial.print(MQ2calcR0/10); Serial.print(" | ");
+  Serial.print(MQ3calcR0/10); Serial.print(" | ");
+  Serial.print(MQ4calcR0/10); Serial.print(" | ");
+  Serial.print(MQ5calcR0/10); Serial.print(" | ");
+  Serial.print(MQ6calcR0/10); Serial.print(" | ");
+  Serial.print(MQ7calcR0/10); Serial.print(" | ");
+  Serial.print(MQ8calcR0/10); Serial.print(" | ");
+  Serial.print(MQ9calcR0/10); Serial.println(" |");
+
+  if(isinf(MQ2calcR0) || isinf(MQ3calcR0) || isinf(MQ4calcR0) || isinf(MQ5calcR0)  || isinf(MQ6calcR0) || isinf(MQ7calcR0) || isinf(MQ8calcR0) || isinf(MQ9calcR0)) {Serial.println("Warning: Conection issue founded, R0 is infite (Open circuit detected) please check your wiring and supply"); while(1);}
+  if(MQ2calcR0 == 0 || MQ3calcR0 == 0 || MQ4calcR0 == 0 || MQ5calcR0 == 0 || MQ6calcR0 == 0 || MQ7calcR0 == 0 || MQ8calcR0 == 0 || MQ9calcR0 == 0){Serial.println("Warning: Conection issue founded, R0 is zero (Analog pin with short circuit to ground) please check your wiring and supply"); while(1);}
+  /*****************************  MQ CAlibration ********************************************/ 
+ 
   //Print in serial monitor
-  Serial.print("MQ2 to MQ9 - lecture");
+  Serial.println("MQ2 to MQ9 - lecture");
+  Serial.println("*************************** Lectures from MQ-board ***************************");
+  Serial.println("|    LPG   |  Benzene |   CH4    |    H2    |   CH4    |    CO    |    H2    |    LPG   |");  
+  Serial.println("|    MQ-2  |   MQ-3   |   MQ-4   |   MQ-5   |   MQ-6   |   MQ-7   |   MQ-8   |   MQ-9   |");  
   //pinMode(calibration_button, INPUT);
 }
 
@@ -125,24 +200,22 @@ void loop() {
   }
   */
   //Read the sensor and print in serial port
-  LPG =  MQ2.readSensor();
+  float MQ2Lecture =  MQ2.readSensor();
-  Alcohol =  MQ3.readSensor();
+  float MQ3Lecture =  MQ3.readSensor();
-  CH4 =  MQ4.readSensor();
+  float MQ4Lecture =  MQ4.readSensor();
-  H2 =  MQ5.readSensor();
+  float MQ5Lecture =  MQ5.readSensor();
-  CH42 =  MQ6.readSensor();
+  float MQ6Lecture =  MQ6.readSensor();
-  CO =  MQ7.readSensor();
+  float MQ7Lecture =  MQ7.readSensor();
-  H22 =  MQ8.readSensor();
+  float MQ8Lecture =  MQ8.readSensor();
-  LPG2 =  MQ9.readSensor();
+  float MQ9Lecture =  MQ9.readSensor();
 
-  Serial.println("***************************");
+  Serial.print("| "); Serial.print(MQ2Lecture);
-  Serial.println("Lectures for MQ-Board");
+  Serial.print("   |   "); Serial.print(MQ3Lecture);
-  Serial.print("LPG: ");Serial.print(LPG,2);Serial.println(" PPM");
+  Serial.print("   |   "); Serial.print(MQ4Lecture);
-  Serial.print("Alcohol: ");Serial.print(Alcohol,2);Serial.println(" PPM");
+  Serial.print("   |   "); Serial.print(MQ5Lecture);
-  Serial.print("CH4: ");Serial.print(CH4,2);Serial.println(" PPM");
+  Serial.print("   |   "); Serial.print(MQ6Lecture);
-  Serial.print("H2: ");Serial.print(H2,2);Serial.println(" PPM");
+  Serial.print("   |   "); Serial.print(MQ7Lecture);
-  Serial.print("CH4_2: ");Serial.print(CH42,2);Serial.println(" PPM");
+  Serial.print("   |   "); Serial.print(MQ8Lecture);
-  Serial.print("CO: ");Serial.print(CO,2);Serial.println(" PPM");
+  Serial.print("   |   "); Serial.print(MQ9Lecture);
-  Serial.print("H2_2: ");Serial.print(H22,2);Serial.println(" PPM");
+  Serial.println("|");
-  Serial.print("LPG_2: ");Serial.print(LPG2,2);Serial.println(" PPM");
-  Serial.println("***************************");  
 }

examples/smokeDetector/smokeDetector.ino

@@ -19,9 +19,10 @@
 //Definitions
 #define placa "Arduino UNO"
 #define Voltage_Resolution 5
-#define pin A0 //Analog input 0 of your arduino
+#define pin A4 //Analog input 0 of your arduino
 #define type "MQ-4" //MQ4
 #define ADC_Bit_Resolution 10 // For arduino UNO/MEGA/NANO
+#define RatioMQ4CleanAir 4.4  //RS / R0 = 4.4 ppm 
 //#define calibration_button 13 //Pin to calibrate your sensor
 
 //Declare Sensor
@@ -47,13 +48,34 @@ void setup() {
   /************************************************************************************/ 
   MQ4.init(); 
   
-  // Calibration setup
+  /*****************************  MQ CAlibration ********************************************/ 
-  MQ4.setR0(3.86018237);
+  // Explanation: 
+  // In this routine the sensor will measure the resistance of the sensor supposing before was pre-heated
+  // and now is on clean air (Calibration conditions), and it will setup R0 value.
+  // We recomend execute this routine only on setup or on the laboratory and save on the eeprom of your arduino
+  // This routine not need to execute to every restart, you can load your R0 if you know the value
+  // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
+  Serial.print("Calibrating please wait.");
+  float calcR0 = 0;
+  for(int i = 0; i<=10; i ++)
+  {
+    MQ4.update(); // Update data, the arduino will be read the voltage on the analog pin
+    calcR0 += MQ4.calibrate(RatioMQ4CleanAir);
+    Serial.print(".");
+  }
+  MQ4.setR0(calcR0/10);
+  Serial.println("  done!.");
+  
+  if(isinf(calcR0)) {Serial.println("Warning: Conection issue founded, R0 is infite (Open circuit detected) please check your wiring and supply"); while(1);}
+  if(calcR0 == 0){Serial.println("Warning: Conection issue founded, R0 is zero (Analog pin with short circuit to ground) please check your wiring and supply"); while(1);}
+  /*****************************  MQ CAlibration ********************************************/ 
+
   
   /* 
     //If the RL value is different from 10K please assign your RL value with the following method:
     MQ4.setRL(10);
   */
+  MQ4.serialDebug(true);
 }
 
   void loop() {
@@ -64,9 +86,8 @@ void setup() {
   ************************************************************************************/ 
   //Read the sensor and print in serial port
   //Lecture will be saved in lecture variable
-  int lecture =  MQ4.readSensor(); // Return smoke concentration
+  MQ4.update();
-  Serial.print("MQ4 smoke ppm lecture: ");
+  MQ4.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted before or in the setup
-  Serial.print(lecture);
+  MQ4.serialDebug(); // Will print the table on the serial port
-  Serial.println(" ppm");
+  delay(400);  
-  delay(400);
 }

src/MQUnifiedsensor.h

@@ -7,7 +7,7 @@
 /***********************Software Related Macros************************************/
 
 #define ADC_RESOLUTION 10 // for 10bit analog to digital converter.
-#define retries 5
+#define retries 2
 #define retry_interval 20
 
 class MQUnifiedsensor