Added MQ136 Example

README.md

@@ -31,6 +31,7 @@ We present a unified library for MQ sensors, this library allows to read MQ sign
 * [Sensor manufacturers](#Sensor-manufacturers)
 * [Contributing](#Contributing)
 * [Authors](#Authors)
+* [Be a sponsor 💖](#sponsor)
 
 ## Getting Started
 
@@ -130,6 +131,7 @@ You'll need Arduino desktop app 1.8.9 or later.
 | MQ-9 | Haoyuelectronics | [datasheet](http://www.haoyuelectronics.com/Attachment/MQ-9/MQ9.pdf) |
 | MQ-131 | Sensorsportal | [datasheet](http://www.sensorsportal.com/DOWNLOADS/MQ131.pdf) |
 | MQ-135 | HANWEI Electronics | [datasheet](https://www.electronicoscaldas.com/datasheet/MQ-135_Hanwei.pdf) |
+| MQ-136 | HANWEI Electronics | [datasheet](https://github.com/miguel5612/MQSensorsLib_Docs/blob/master/Datasheets/MQ136%20-%20Hanwei.pdf) |
 | MQ-303A | HANWEI Electronics | [datasheet](http://www.kosmodrom.com.ua/pdf/MQ303A.pdf) |
 | MQ-309A | HANWEI Electronics | [datasheet](http://www.sensorica.ru/pdf/MQ-309A.pdf) |
 
@@ -242,6 +244,10 @@ This project is licensed under the MIT License - see the [LICENSE.md](LICENSE.md
 }
 
 
+## sponsor
+
+* [Paypal](https://www.paypal.com/paypalme/miguel5612)
+
 
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examples/MQ-136/MQ-136.ino

@@ -0,0 +1,88 @@
+/*
+  MQUnifiedsensor Library - reading an MQ136
+
+  Demonstrates the use a MQ136 sensor.
+  Library originally added 01 may 2019
+  by Miguel A Califa, Yersson Carrillo, Ghiordy Contreras, Mario Rodriguez
+ 
+  Added example
+  modified 21 March 2022
+  by Miguel Califa 
+
+  Wiring:
+  https://github.com/miguel5612/MQSensorsLib_Docs/blob/master/static/img/MQ_Arduino.PNG
+  Please make sure arduino A0 pin represents the analog input configured on #define pin
+
+ This example code is in the public domain.
+
+*/
+
+//Include the library
+#include <MQUnifiedsensor.h>
+
+//Definitions
+#define placa "Arduino UNO"
+#define Voltage_Resolution 5
+#define pin A0 //Analog input 0 of your arduino
+#define type "MQ-136" //MQ136
+#define ADC_Bit_Resolution 10 // For arduino UNO/MEGA/NANO
+#define RatioMQ136CleanAir 3.6//RS / R0 = 3.6 ppm  
+//#define calibration_button 13 //Pin to calibrate your sensor
+
+//Declare Sensor
+MQUnifiedsensor MQ136(placa, Voltage_Resolution, ADC_Bit_Resolution, pin, type);
+
+void setup() {
+  //Init the serial port communication - to debug the library
+  Serial.begin(9600); //Init serial port
+
+  //Set math model to calculate the PPM concentration and the value of constants
+  MQ136.setRegressionMethod(1); //_PPM =  a*ratio^b
+  MQ136.setA(1043.3); MQ136.setB(-3.282); // Configure the equation to to calculate H2S Concentration
+
+  /*
+    Exponential regression:
+  GAS      | a      | b
+  H2S      | 1043.3 | -3.282  
+  NH4      | 309.6  | -1.407 
+  CO       | 1728.9 | -1.879
+  */
+  
+  /*****************************  MQ Init ********************************************/ 
+  //Remarks: Configure the pin of arduino as input.
+  /************************************************************************************/ 
+  MQ136.init(); 
+  /* 
+    //If the RL value is different from 10K please assign your RL value with the following method:
+    MQ136.setRL(10);
+  */
+  /*****************************  MQ CAlibration ********************************************/ 
+  // Explanation: 
+   // In this routine the sensor will measure the resistance of the sensor supposedly before being pre-heated
+  // and on clean air (Calibration conditions), setting up R0 value.
+  // We recomend executing this routine only on setup in laboratory conditions.
+  // This routine does not need to be executed on each restart, you can load your R0 value from eeprom.
+  // Acknowledgements: https://jayconsystems.com/blog/understanding-a-gas-sensor
+  Serial.print("Calibrating please wait.");
+  float calcR0 = 0;
+  for(int i = 1; i<=10; i ++)
+  {
+    MQ136.update(); // Update data, the arduino will read the voltage from the analog pin
+    calcR0 += MQ136.calibrate(RatioMQ136CleanAir);
+    Serial.print(".");
+  }
+  MQ136.setR0(calcR0/10);
+  Serial.println("  done!.");
+  
+  if(isinf(calcR0)) {Serial.println("Warning: Conection issue, R0 is infinite (Open circuit detected) please check your wiring and supply"); while(1);}
+  if(calcR0 == 0){Serial.println("Warning: Conection issue found, R0 is zero (Analog pin shorts to ground) please check your wiring and supply"); while(1);}
+  /*****************************  MQ CAlibration ********************************************/ 
+  MQ136.serialDebug(true);
+}
+
+void loop() {
+  MQ136.update(); // Update data, the arduino will read the voltage from the analog pin
+  MQ136.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  MQ136.serialDebug(); // Will print the table on the serial port
+  delay(500); //Sampling frequency
+}