Added examples in comments

examples/MQ-4/MQ-4.ino

@@ -42,11 +42,11 @@ void loop() {
   ************************************************************************************/ 
   //Read the sensor and print in serial port
   //Lecture will be saved in lecture variable
-  int lecture =  MQ3.readSensor("", true); // Return Alcohol concentration
+  int lecture =  MQ4.readSensor("", true); // Return CH4 concentration
   // Options, uncomment where you need
-  //int lecture =  MQ3.readSensor("CH4", true); // Return CH4 concentration
-  //int lecture =  MQ3.readSensor("LPG", true); // Return LPG concentration
-  //int lecture =  MQ3.readSensor("CO", true); // Return CO concentration
-  //int lecture =  MQ3.readSensor("Alcohol", true); // Return Alcohol concentration
-  //int lecture =  MQ3.readSensor("smoke", true); // Return smoke concentration
+  //int lecture =  MQ4.readSensor("CH4", true); // Return CH4 concentration
+  //int lecture =  MQ4.readSensor("LPG", true); // Return LPG concentration
+  //int lecture =  MQ4.readSensor("CO", true); // Return CO concentration
+  //int lecture =  MQ4.readSensor("Alcohol", true); // Return Alcohol concentration
+  //int lecture =  MQ4.readSensor("smoke", true); // Return smoke concentration
 }

examples/MQ-5/MQ-5.ino

@@ -26,16 +26,27 @@ MQUnifiedsensor MQ5(pin, type);
 
 void setup() {
    //init the sensor
+  /*****************************  MQInicializar****************************************
+  Input:  pin, type 
+  Output:  
+  Remarks: This function create the sensor object.
+  ************************************************************************************/ 
   MQ5.inicializar(); 
 }
 
 void loop() {
-  //Read the sensor
-  int read =  MQ5.readSensor();
-  //Print measurements
-  Serial.print("MQ5: ");
-  Serial.print(read);
-  Serial.println(" PPM");
-  //delay 1s to next measure
-  delay(1000);
+  /*****************************  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
+  int lecture =  MQ5.readSensor("", true); // Return H2 concentration
+  // Options, uncomment where you need
+  //int lecture =  MQ5.readSensor("H2", true); // Return CH4 concentration
+  //int lecture =  MQ5.readSensor("LPG", true); // Return LPG concentration
+  //int lecture =  MQ5.readSensor("CH4", true); // Return CO concentration
+  //int lecture =  MQ5.readSensor("CO", true); // Return Alcohol concentration
+  //int lecture =  MQ5.readSensor("Alcohol", true); // Return smoke concentration
 }