Updated examples to MQ-4

examples/MQ-2/MQ-2.ino

@@ -31,9 +31,6 @@
 //Declare Sensor
 MQUnifiedsensor MQ2(placa, Voltage_Resolution, ADC_Bit_Resolution, pin, type);
 
-//Variables
-float CH4, LPG, CO, Alcohol, Hexane, Benzine;
-
 void setup() {
   //Init the serial port communication - to debug the library
   Serial.begin(9600); //Init serial port

examples/MQ-3/MQ-3.ino

@@ -31,9 +31,6 @@
 //Declare Sensor
 MQUnifiedsensor MQ3(placa, Voltage_Resolution, ADC_Bit_Resolution, pin, type);
 
-//Variables
-float CH4, LPG, CO, Alcohol, Hexane, Benzine;
-
 void setup() {
   //Init the serial port communication - to debug the library
   Serial.begin(9600); //Init serial port
@@ -41,7 +38,17 @@ void setup() {
   //Set math model to calculate the PPM concentration and the value of constants
   MQ3.setRegressionMethod("Exponential"); //_PPM =  a*ratio^b
   MQ3.setA(4.8387); MQ3.setB(-2.68); // Configurate the ecuation values to get Benzene concentration
-  
+  /*
+    Exponential regression:
+  Gas    | a      | b
+  LPG    | 44771  | -3.245
+  CH4    | 2*10^31| 19.01
+  CO     | 521853 | -3.821
+  Alcohol| 0.3934 | -1.504
+  Benzene| 4.8387 | -2.68
+  Hexane | 7585.3 | -2.849
+  */
+
   // Calibration setup
   MQ3.setR0(3.86018237);
 

examples/MQ-4/MQ-4.ino

@@ -9,6 +9,10 @@
   modified 23 May 2019
   by Miguel Califa 
 
+  Updated library usage
+  modified 26 March 2020
+  by Miguel Califa 
+
  This example code is in the public domain.
 
 */
@@ -17,65 +21,57 @@
 #include <MQUnifiedsensor.h>
 
 //Definitions
+#define placa "Arduino UNO"
+#define Voltage_Resolution 5
 #define pin A0 //Analog input 0 of your arduino
-#define type 4 //MQ4
+#define type "MQ-4" //MQ4
+#define ADC_Bit_Resolution 10 // For arduino UNO/MEGA/NANO
 //#define calibration_button 13 //Pin to calibrate your sensor
 
 //Declare Sensor
-MQUnifiedsensor MQ4(pin, type);
+MQUnifiedsensor MQ4(placa, Voltage_Resolution, ADC_Bit_Resolution, pin, type);
-
-//Variables
-float CH4, LPG, CO, Alcohol, smoke;
 
 void setup() {
+  //Init the serial port communication - to debug the library
   Serial.begin(9600); //Init serial port
-  //init the sensor
-  /*****************************  MQInicializar****************************************
-  Input:  pin, type 
-  Output:  
-  Remarks: This function create the sensor object.
-  ************************************************************************************/ 
-  MQ4.inicializar(); 
-  //pinMode(calibration_button, INPUT);
-}
 
-void loop() {
+  //Set math model to calculate the PPM concentration and the value of constants
-  MQ4.update(); // Update data, the arduino will be read the voltaje in the analog pin
+  MQ4.setRegressionMethod("Exponential"); //_PPM =  a*ratio^b
-  /* 
+  MQ4.setA(4.8387); MQ4.setB(-2.68); // Configurate the ecuation values to get Benzene concentration
-  //Si el valor de RL es diferente a 10K por favor asigna tu valor de RL con el siguiente metodo:
-    MQ4.setRL(10);
-  */
   /*
-  //Rutina de calibracion - Uncomment if you need (setup too and header)
+    Exponential regression:
-  if(calibration_button)
+  Gas    | a      | b
-  {
+  LPG    | 3811.9 | -3.113
-    float R0 = MQ4.calibrate();
+  CH4    | 1012.7 | -2.786
-    MQ4.setR0(R0);
+  CO     | 200000000000000 | -19.05
-  }
+  Alcohol| 60000000000 | -14.01
+  smoke  | 30000000 | -8.308
   */
-  /*****************************  MQReadSensor  ****************************************
+
-  Input:   Gas - Serial print flag
-  Output:  Value in PPM
-  Remarks: This function use readPPM to read the value in PPM the gas in the air.
-  ************************************************************************************/ 
-  //Read the sensor and print in serial port
-  //Lecture will be saved in lecture variable
-  //float lecture =  MQ4.readSensor("", true); // Return CH4 concentration
-  // Options, uncomment where you need
-  CH4 =  MQ4.readSensor("CH4"); // Return CH4 concentration
-  LPG =  MQ4.readSensor("LPG"); // Return LPG concentration
-  CO =  MQ4.readSensor("CO"); // Return CO concentration
-  Alcohol =  MQ4.readSensor("Alcohol"); // Return Alcohol concentration
-  smoke =  MQ4.readSensor("smoke"); // Return smoke concentration
   
-  Serial.println("***************************");
+  // Calibration setup
-  Serial.println("Lectures for MQ-4");
+  MQ4.setR0(3.86018237);
-  Serial.print("Volt: ");Serial.print(MQ4.getVoltage(false));Serial.println(" V"); 
+
-  Serial.print("R0: ");Serial.print(MQ4.getR0());Serial.println(" Ohm"); 
+  /* 
-  Serial.print("CH4: ");Serial.print(CH4,2);Serial.println(" ppm");
+    //If the RL value is different from 10K please assign your RL value with the following method:
-  Serial.print("LPG: ");Serial.print(LPG,2);Serial.println(" ppm");
+    MQ4.setRL(10);
-  Serial.print("CO: ");Serial.print(CO,2);Serial.println(" ppm");
+  */
-  Serial.print("Alcohol: ");Serial.print(Alcohol,2);Serial.println(" ppm");
+
-  Serial.print("smoke: ");Serial.print(smoke,2);Serial.println(" ppm");
+  /*****************************  MQ Init ********************************************/ 
-  Serial.println("***************************");
+  //Remarks: Configure the pin of arduino as input.
+  /************************************************************************************/ 
+  MQ4.init(); 
+  /*****************************  MQ Init ********************************************/ 
+  //Input: setup flag, if this function are on setup will print the headers (Optional - Default value: False)
+  //Output: print on serial port the information about sensor and sensor readings
+  //Remarks: Configure the pin of arduino as input.
+  /************************************************************************************/ 
+  MQ4.serialDebug(true);
 }
+
+void loop() {
+  MQ4.update(); // Update data, the arduino will be read the voltage on the analog pin
+  MQ4.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted before or in the setup
+  MQ4.serialDebug(); // Will print the table on the serial port
+  delay(500); //Sampling frequency
+}