diff --git a/.vscode/ipch/d0f8e6bab5989cc8/mmap_address.bin b/.vscode/ipch/d0f8e6bab5989cc8/mmap_address.bin
new file mode 100644
index 0000000..862b842
Binary files /dev/null and b/.vscode/ipch/d0f8e6bab5989cc8/mmap_address.bin differ
diff --git a/examples/MQ-Board-Calibration/MQ-Board-Calibration.ino b/examples/MQ-Board-Calibration/MQ-Board-Calibration.ino
index 4dc6424..1871cdb 100644
--- a/examples/MQ-Board-Calibration/MQ-Board-Calibration.ino
+++ b/examples/MQ-Board-Calibration/MQ-Board-Calibration.ino
@@ -9,6 +9,14 @@
   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 
+
  This example code is in the public domain.
 
 */
@@ -32,6 +40,7 @@ LiquidCrystal_I2C lcd(0x27, 16, 2);
 #define pin8 A8 //Analog input 8 of your arduino
 #define pin9 A9 //Analog input 9 of your arduino
 
+#define timeDelay 500
 //Declare Sensor
 
 MQUnifiedsensor MQ2(pin2, 2);
@@ -67,14 +76,14 @@ void setup() {
   MQ6.inicializar(); 
   MQ7.inicializar(); 
   MQ8.inicializar(); 
-  //MQ9.inicializar();
+  MQ9.inicializar();
   
   //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("Autonumeric, MQ2(PPM), MQ3(PPM), MQ4(PPM), MQ5(PPM), MQ6(PPM), MQ7(PPM)");
   //Wait one second to continue
-  delay(1000);
+  delay(timeDelay/10);
 }
 
 void loop() {
@@ -103,7 +112,7 @@ void loop() {
   lcd.print("MQ3: ");
   lcd.print(lecture3);
   lcd.print(" PPM");
-  delay(2000);
+  delay(timeDelay/4);
   lcd.clear();
   lcd.setCursor(0,0);
   lcd.print("MQ4: ");
@@ -113,7 +122,7 @@ void loop() {
   lcd.print("MQ5: ");
   lcd.print(lecture5);
   lcd.print(" PPM");
-  delay(2000);
+  delay(timeDelay/4);
   lcd.clear();
   lcd.setCursor(0,0);
   lcd.print("MQ6: ");
@@ -123,7 +132,7 @@ void loop() {
   lcd.print("MQ7: ");
   lcd.print(lecture7);
   lcd.print(" PPM");
-  delay(2000);
+  delay(timeDelay/4);
   lcd.clear();
   lcd.setCursor(0,0);
   lcd.print("MQ8: ");
@@ -133,10 +142,10 @@ void loop() {
   lcd.print("MQ8: ");
   lcd.print(lecture8);
   lcd.print(" PPM");
-  delay(2000);
+  delay(timeDelay/4);
 
   //Increment counter
   contador++;
   //Wait to measure next sample
-  delay(400);
+  delay(timeDelay/4);
 }
diff --git a/src/MQUnifiedsensor.h b/src/MQUnifiedsensor.h
index 46b872c..8f283d3 100644
--- a/src/MQUnifiedsensor.h
+++ b/src/MQUnifiedsensor.h
@@ -40,18 +40,18 @@
 
 //Values consolidated
 /* Gas, Value of m (Slope) and b (Cut on x axis) points */
-const String _MQ2[18] = {"H2","-2.2459","2.9845","LPG","-2.2879","2.7901","CO","-2.6208","3.6075","Alcohol","-3.1157","4.5134","Propane","-2.7028","3.5595","Benzene","-2.2879","2.7901"};
-const String _MQ3[18] = {"LPG","-3.1851","4.7048","CH4","-17.531","28.785","CO","-4.339","6.4432","Alcohol","-1.435","0.4103","Benzene","-2.7009","0.632","Hexane","-2.7268","3.6299"};
-const String _MQ4[15] = {"LPG","-2.5818","3.6303","CH4","0.9873","2.6386","CO","-5.5945","5.6693","Alcohol","-11.89","9.0375","smoke","-11.189","9.0375"};
-const String _MQ5[15] = {"H2","-4.368","2.9667","LPG","-2.5723","1.8943","CH4","-2.4438","2.3044","CO","-4.8188","5.2023","Alcohol","-4.419","4.8044"};
-const String _MQ6[15] = {"H2","-3.6775","5.0286","LPG","-1.6567","2.8775","CH4","-1","3.301","CO","-12.791","14.523","Alcohol","-5.8057","7.5292"};
-const String _MQ7[15] = {"H2","-1.329","1.8864","LPG","-7.8626","9.1056","CH4","-5.4878","8.8387","CO","-1.4065","2.0162","Alcohol","-6.3219","9.924"};
-const String _MQ8[15] = {"H2","-0.7152","2.9891","LPG","-3.419","7.3513","CH4","-7.5609","15.243","CO","-7.0753","15.396","Alcohol","-1.7459","4.7575"};
-const String _MQ9[9] = {"LPG","-2.2535","2.9855","CH4","-1.6012","3.1476","CO","-1.749","2.827"};
-const String _MQ131[9] = {"Nox","-2.7245","3.3004","CL2","-1.0333","1.7117","O3","-1.2037","1.6455"};
-const String _MQ135[18] = {"CO","-2.7268","2.301","Alcohol","-2.8608","1.8627","CO2","-3.2819","1.9903","Tolueno","-5.7015","1.1612","NH4","-2.2119","2.0473","Acetona","-5.9682","1.0175"};
-const String _MQ303A[9] = {"Iso-butano","-2.3543","1.144","Hydrogeno","-2.4338","0.7558","Ethanol","-2.5597","0.4436"};
-const String _MQ309A[12] = {"H2","-2.1311","3.0886","CH4","-1.6554","2.985","CO","-4.7623","6.7413","Alcohol","-3.7686","5.6744"};
+const String PROGMEM _MQ2[18] = {"H2","-2.2459","2.9845","LPG","-2.2879","2.7901","CO","-2.6208","3.6075","Alcohol","-3.1157","4.5134","Propane","-2.7028","3.5595","Benzene","-2.2879","2.7901"};
+const String PROGMEM _MQ3[18] = {"LPG","-3.1851","4.7048","CH4","-17.531","28.785","CO","-4.339","6.4432","Alcohol","-1.435","0.4103","Benzene","-2.7009","0.632","Hexane","-2.7268","3.6299"};
+const String PROGMEM _MQ4[15] = {"LPG","-2.5818","3.6303","CH4","0.9873","2.6386","CO","-5.5945","5.6693","Alcohol","-11.89","9.0375","smoke","-11.189","9.0375"};
+const String PROGMEM _MQ5[15] = {"H2","-4.368","2.9667","LPG","-2.5723","1.8943","CH4","-2.4438","2.3044","CO","-4.8188","5.2023","Alcohol","-4.419","4.8044"};
+const String PROGMEM _MQ6[15] = {"H2","-3.6775","5.0286","LPG","-1.6567","2.8775","CH4","-1","3.301","CO","-12.791","14.523","Alcohol","-5.8057","7.5292"};
+const String PROGMEM _MQ7[15] = {"H2","-1.329","1.8864","LPG","-7.8626","9.1056","CH4","-5.4878","8.8387","CO","-1.4065","2.0162","Alcohol","-6.3219","9.924"};
+const String PROGMEM _MQ8[15] = {"H2","-0.7152","2.9891","LPG","-3.419","7.3513","CH4","-7.5609","15.243","CO","-7.0753","15.396","Alcohol","-1.7459","4.7575"};
+const String PROGMEM _MQ9[9] = {"LPG","-2.2535","2.9855","CH4","-1.6012","3.1476","CO","-1.749","2.827"};
+const String PROGMEM _MQ131[9] = {"Nox","-2.7245","3.3004","CL2","-1.0333","1.7117","O3","-1.2037","1.6455"};
+const String PROGMEM _MQ135[18] = {"CO","-2.7268","2.301","Alcohol","-2.8608","1.8627","CO2","-3.2819","1.9903","Tolueno","-5.7015","1.1612","NH4","-2.2119","2.0473","Acetona","-5.9682","1.0175"};
+const String PROGMEM _MQ303A[9] = {"Iso-butano","-2.3543","1.144","Hydrogeno","-2.4338","0.7558","Ethanol","-2.5597","0.4436"};
+const String PROGMEM _MQ309A[12] = {"H2","-2.1311","3.0886","CH4","-1.6554","2.985","CO","-4.7623","6.7413","Alcohol","-3.7686","5.6744"};
 
 class MQUnifiedsensor
 {