diff --git a/examples/easyC/MQ-138-ALL-easyC/MQ-138-ALL-easyC.ino b/examples/easyC/MQ-138-ALL-easyC/MQ-138-ALL-easyC.ino
new file mode 100644
index 0000000..7bb8c1f
--- /dev/null
+++ b/examples/easyC/MQ-138-ALL-easyC/MQ-138-ALL-easyC.ino
@@ -0,0 +1,128 @@
+/*
+  MQUnifiedsensor Library - reading an mq138
+
+  Demonstrates the use a mq138 sensor.
+  Library originally added 01 may 2019
+  by Miguel A Califa, Yersson Carrillo, Ghiordy Contreras, Mario Rodriguez
+
+  Added example
+  modified 23 May 2019
+  by Miguel Califa
+
+  Updated library usage
+  modified 26 March 2020
+  by Miguel Califa
+
+  Example is modified by Soldered.com
+
+  Wiring:
+  https://github.com/miguel5612/MQSensorsLib_Docs/blob/master/static/img/MQ_Arduino.PNG
+
+
+ This example code is in the public domain.
+
+*/
+
+// Include the library
+#include "MQ-Sensor-SOLDERED.h"
+
+// Predefined microcontroller pins for AO sensor pin (microcontroller dependent)
+// You can change the pin to suit your setup.
+#if defined(__AVR__) || defined(STM32)
+#define SENSOR_ANALOG_PIN A1
+#elif defined(ESP32)
+#define SENSOR_ANALOG_PIN 34
+#else
+#define SENSOR_ANALOG_PIN 5
+#endif
+
+#define Ratiomq138CleanAir 3.6 // RS / R0 = 3.6 ppm
+
+// Create library object for this specific sensor.
+MQ138 mq138(SENSOR_ANALOG_PIN);
+
+void setup()
+{
+    // Init the serial port communication at 115200 bauds. It's used to print out measured data.
+    Serial.begin(115200);
+
+    // Set math model to calculate the PPM concentration and the value of constants
+    mq138.setRegressionMethod(1); //_PPM =  a*ratio^b
+
+    /*****************************  MQ Init ********************************************/
+    // Remarks: Configure the pin of arduino as input.
+    /************************************************************************************/
+    mq138.begin(0x30); // If you have easyC version of this sensor
+                   // you should add here I2C address of sensor
+                   // which is 0x30 by default and can be changed
+                   // by onboard switches labeled with ADDR
+    /*
+      //If the RL value is different from 10K please assign your RL value with the following method:
+      mq138.setRL(10);
+    */
+    /*****************************  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 calcR0 = 0;
+    for (int i = 1; i <= 10; i++)
+    {
+        mq138.update(); // Update data, the arduino will be read the voltage on the analog pin
+        calcR0 += mq138.calibrate(Ratiomq138CleanAir);
+        Serial.print(".");
+    }
+    mq138.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 ********************************************/
+    Serial.println("** Readings from MQ-138 ****");
+    Serial.println("|    H2S   |  Ethanol |   Toulene |");
+}
+
+void loop()
+{
+    mq138.update(); // Update data, the arduino will be read the voltage on the analog pin
+
+    mq138.setA(9.4784);
+    mq138.setB(-2.334);            // Configurate the ecuation values to get H2S concentration
+    float H2S = mq138.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted
+                                   // before or in the setup
+
+    mq138.setA(33.119);
+    mq138.setB(-2.847);                  // Configurate the ecuation values to get Ethanol concentration
+    float Ethanol = mq138.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted
+                                        // before or in the setup
+
+    mq138.setA(168.48);
+    mq138.setB(-3.116);             // Configurate the ecuation values to get Toulene concentration
+    float Toulene = mq138.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted
+                                    // before or in the setup
+
+    Serial.print("|   ");
+    Serial.print(H2S);
+    Serial.print("   |   ");
+    Serial.print(Ethanol);
+    Serial.print("   |   ");
+    Serial.print(Toulene);
+    Serial.println("   |   ");
+
+    delay(500); // Sampling frequency
+}
diff --git a/examples/native/MQ-138-ALL/MQ-138-ALL.ino b/examples/native/MQ-138-ALL/MQ-138-ALL.ino
new file mode 100644
index 0000000..29f4dcd
--- /dev/null
+++ b/examples/native/MQ-138-ALL/MQ-138-ALL.ino
@@ -0,0 +1,128 @@
+/*
+  MQUnifiedsensor Library - reading an mq138
+
+  Demonstrates the use a mq138 sensor.
+  Library originally added 01 may 2019
+  by Miguel A Califa, Yersson Carrillo, Ghiordy Contreras, Mario Rodriguez
+
+  Added example
+  modified 23 May 2019
+  by Miguel Califa
+
+  Updated library usage
+  modified 26 March 2020
+  by Miguel Califa
+
+  Example is modified by Soldered.com
+
+  Wiring:
+  https://github.com/miguel5612/MQSensorsLib_Docs/blob/master/static/img/MQ_Arduino.PNG
+
+
+ This example code is in the public domain.
+
+*/
+
+// Include the library
+#include "MQ-Sensor-SOLDERED.h"
+
+// Predefined microcontroller pins for AO sensor pin (microcontroller dependent)
+// You can change the pin to suit your setup.
+#if defined(__AVR__) || defined(STM32)
+#define SENSOR_ANALOG_PIN A1
+#elif defined(ESP32)
+#define SENSOR_ANALOG_PIN 34
+#else
+#define SENSOR_ANALOG_PIN 5
+#endif
+
+#define Ratiomq138CleanAir 3.6 // RS / R0 = 3.6 ppm
+
+// Create library object for this specific sensor.
+MQ138 mq138(SENSOR_ANALOG_PIN);
+
+void setup()
+{
+    // Init the serial port communication at 115200 bauds. It's used to print out measured data.
+    Serial.begin(115200);
+
+    // Set math model to calculate the PPM concentration and the value of constants
+    mq138.setRegressionMethod(1); //_PPM =  a*ratio^b
+
+    /*****************************  MQ Init ********************************************/
+    // Remarks: Configure the pin of arduino as input.
+    /************************************************************************************/
+    mq138.begin(); // If you have easyC version of this sensor
+                   // you should add here I2C address of sensor
+                   // which is 0x30 by default and can be changed
+                   // by onboard switches labeled with ADDR
+    /*
+      //If the RL value is different from 10K please assign your RL value with the following method:
+      mq138.setRL(10);
+    */
+    /*****************************  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 calcR0 = 0;
+    for (int i = 1; i <= 10; i++)
+    {
+        mq138.update(); // Update data, the arduino will be read the voltage on the analog pin
+        calcR0 += mq138.calibrate(Ratiomq138CleanAir);
+        Serial.print(".");
+    }
+    mq138.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 ********************************************/
+    Serial.println("** Readings from MQ-138 ****");
+    Serial.println("|    H2S   |  Ethanol |   Toulene |");
+}
+
+void loop()
+{
+    mq138.update(); // Update data, the arduino will be read the voltage on the analog pin
+
+    mq138.setA(9.4784);
+    mq138.setB(-2.334);            // Configurate the ecuation values to get H2S concentration
+    float H2S = mq138.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted
+                                   // before or in the setup
+
+    mq138.setA(33.119);
+    mq138.setB(-2.847);                  // Configurate the ecuation values to get Ethanol concentration
+    float Ethanol = mq138.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted
+                                        // before or in the setup
+
+    mq138.setA(168.48);
+    mq138.setB(-3.116);             // Configurate the ecuation values to get Toulene concentration
+    float Toulene = mq138.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted
+                                    // before or in the setup
+
+    Serial.print("|   ");
+    Serial.print(H2S);
+    Serial.print("   |   ");
+    Serial.print(Ethanol);
+    Serial.print("   |   ");
+    Serial.print(Toulene);
+    Serial.println("   |   ");
+
+    delay(500); // Sampling frequency
+}