Added parenthesis to make clear the operation

README.md

@@ -1,45 +1,118 @@
+<!-- PROJECT SHIELDS -->
+<!--
+*** I'm using markdown "reference style" links for readability.
+*** Reference links are enclosed in brackets [ ] instead of parentheses ( ).
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 [![DOI](https://zenodo.org/badge/170540207.svg)](https://zenodo.org/badge/latestdoi/170540207)
-![Build Status](https://travis-ci.org/dwyl/esta.svg?branch=master)
+![Build Status][build-url]
+[![Contributors][contributors-shield]][contributors-url]
+[![Forks][forks-shield]][forks-url]
+[![Stargazers][stars-shield]][stars-url]
+[![Issues][issues-shield]][issues-url]
+[![MIT License][license-shield]][license-url]
+[![LinkedIn][linkedin-shield]][linkedin-url]
 
 # MQSensorsLib
 
 This is a unified library to use sensors MQ: 2, 3, 4, 5, 6, 7, 8, 9, 131, 135, 303A and 309A.
 
+<!-- TABLE OF CONTENTS -->
+## Table of Contents
+
+* [Getting Started](#Getting-Started)
+* [Wiring](#Wiring)
+  * [Sensor](#Sensor)
+  * [Arduino](#Arduino)
+  * [ESP8266](#ESP8266)
+* [User Manual](#usage)
+* [Sensor manufacturers](#Sensor-manufacturers)
+* [Contributing](#Contributing)
+* [Authors](#Authors)
+
 ## Getting Started
 
 ```
-#define placa "Arduino UNO"
-#define Voltage_Resolution 5
-#define pin A0 //Analog input 0 of your arduino
-#define type "MQ-4" //MQ4
-#define ADC_Bit_Resolution 10 // For arduino UNO/MEGA/NANO
-MQUnifiedsensor MQ4(placa, Voltage_Resolution, ADC_Bit_Resolution, pin, type); //Example if sensor is MQ4 on Arduino UNO board
+//Include the library
+#include <MQUnifiedsensor.h>
+/************************Hardware Related Macros************************************/
+#define         Board                   ("Arduino UNO")
+#define         Pin                     (A4)  //Analog input 4 of your arduino
+/***********************Software Related Macros************************************/
+#define         Type                    ("MQ-4") //MQ4
+#define         Voltage_Resolution      (5)
+#define         ADC_Bit_Resolution      (10) // For arduino UNO/MEGA/NANO
+#define         RatioMQ4CleanAir        (4.4) //RS / R0 = 60 ppm 
+/*****************************Globals***********************************************/
+//Declare Sensor
+MQUnifiedsensor MQ4(Board, Voltage_Resolution, ADC_Bit_Resolution, Pin, Type);
+// Setup
 MQ4.setRegressionMethod("Exponential"); //_PPM =  a*ratio^b
 MQ4.setA(1012.7); MQ4.setB(-2.786); // Configurate the ecuation values to get CH4 concentration
-MQ4.setR0(3.86018237);
+MQ4.setR0(3.86018237); // Value getted on calibration
+// Loop
 MQ4.init();
 MQ4.update();
 float ppmCH4 = MQ4.readSensor();
 ```
 
 ## Wiring
-
+### Sensor
+#### Important points:
+##### Points you should identify
+* VCC -> 5V Power supply (+) wire
+* GND -> GND Ground (-) wire
+* AO -> Analog Output of the sensor
+##### Data of board that you should have
+* RL Value in KOhms
+##### Graph
+![Wiring_MQSensor](https://raw.githubusercontent.com/miguel5612/MQSensorsLib_Docs/master/static/img/Points_explanation.jpeg)
+#### RS/R0 value (From datasheet of your sensor)
+* RS/R0 (Clean air - English) -> (Aire puro - Spanish)
+* **Note**: RS/R0 is equal to Ratio variable on the program
+![Graph from datasheet](https://raw.githubusercontent.com/miguel5612/MQSensorsLib_Docs/master/static/img/Graph_Explanation.jpeg)
 ### Arduino
 ![Arduino_Wiring_MQSensor](https://raw.githubusercontent.com/miguel5612/MQSensorsLib_Docs/master/static/img/MQ_Arduino.PNG)
 
 ### ESP8266
 ![ESP8266_Wiring_MQSensor](https://raw.githubusercontent.com/miguel5612/MQSensorsLib_Docs/master/static/img/MQ_ESP8266.PNG)
 
-### User Manual New!! 12.2019
+### User Manual (v1.0) 12.2019
 [Manual](https://drive.google.com/open?id=1BAFInlvqKR7h81zETtjz4_RC2EssvFWX)
+### User Manual (v2.0) 04.2020
+[Manual](https://github.com/miguel5612/MQSensorsLib_Docs/blob/master/Docs/MQSensorLib_2.0.pdf)
 
-[Excel_Help_Spreadsheet (Fill only Volaje Between RL - RS - RL Values)](https://drive.google.com/open?id=1MKDcudQ7BHL_vLGi-lgPh9-pblvygRMq)
+
+### Serial debug (optional)
+If your sensor is an **MQ2** (Same for others sensors):
+* To enable on setup wrote
+```
+MQ2.serialDebug(true); 
+```
+* And on Loop Wrote
+```
+MQ2.serialDebug(); 
+```
+* Result:
+
+![Serial debug output](https://github.com/miguel5612/MQSensorsLib_Docs/blob/master/static/img/Serial_Mon_Explanation.jpeg?raw=true)
+
+**Note**: 
+* ![#c5f015](https://placehold.it/15/c5f015/000000?text=+) `Yellow -> Calibration status.`
+* ![#008000](https://placehold.it/15/008000/000000?text=+) `Green -> Hardware and software characteristics.`
+* ![#f03c15](https://placehold.it/15/f03c15/000000?text=+) `Red -> Headers of the library calculations.`
+* Only valid for **1** gas sensor readings.
+
+**Usage**
+* Quick troubleshooting, since it shows everything the library does and the results of the calculations in each function.
 
 ### Prerequisites
 
 You'll need Arduino desktop app 1.8.9 or later.
 
-### Sensor manufacture:
+### Sensor manufacturers:
 | Sensor | Manufacture | URL Datasheet |
 |----------|----------|----------|
 | MQ-2 | Pololulu| [datasheet](https://www.pololu.com/file/0J309/MQ2.pdf) |
@@ -105,8 +178,8 @@ Please read [CONTRIBUTING.md](https://github.com/miguel5612/MQSensorsLib/blob/ma
 
 ## Collaborators
 
-* **Andres A. Martinez.** 
-* **Juan A. Rodríguez.** - [*Github*](https://github.com/Obiot24)
+* **Andres A. Martinez.** - [*Github*](https://github.com/andresmacsi) - [CV](https://www.linkedin.com/in/andr%C3%A9s-acevedo-mart%C3%ADnez-73ab35185/?originalSubdomain=co)
+* **Juan A. Rodríguez.** - [*Github*](https://github.com/Obiot24) - [CV]()
 * **Mario A. Rodríguez O.** - [*GitHub*](https://github.com/MarioAndresR) - [CV](https://scienti.colciencias.gov.co/cvlac/visualizador/generarCurriculoCv.do?cod_rh=0000111304)
 
 See also the list of [contributors](https://github.com/miguel5612/MQSensorsLib/contributors) who participated in this project.
@@ -158,3 +231,22 @@ This project is licensed under the MIT License - see the [LICENSE.md](LICENSE.md
   doi          = {10.5281/zenodo.3384301},
   url          = {https://doi.org/10.5281/zenodo.3384301}
 }
+
+
+
+<!-- MARKDOWN LINKS & IMAGES -->
+<!-- https://www.markdownguide.org/basic-syntax/#reference-style-links -->
+[contributors-shield]: https://img.shields.io/github/contributors/miguel5612/MQSensorsLib.svg?style=flat-square
+[contributors-url]: https://github.com/miguel5612/MQSensorsLib/graphs/contributors
+[forks-shield]: https://img.shields.io/github/forks/miguel5612/MQSensorsLib.svg?style=flat-square
+[forks-url]: https://github.com/miguel5612/MQSensorsLib/network/members
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+[issues-url]: https://github.com/miguel5612/MQSensorsLib/issues
+[license-shield]: https://img.shields.io/github/license/miguel5612/MQSensorsLib.svg?style=flat-square
+[license-url]: https://github.com/miguel5612/MQSensorsLib/blob/master/LICENSE.txt
+[linkedin-shield]: https://img.shields.io/badge/-LinkedIn-black.svg?style=flat-square&logo=linkedin&colorB=555
+[build-url]: https://travis-ci.org/dwyl/esta.svg?branch=master
+[linkedin-url]: https://www.linkedin.com/in/miguel5612
+[product-screenshot]: images/screenshot.png

examples/ESP32/esp32.ino

@@ -0,0 +1,93 @@
+// This is an example of implementation using ESP8266
+// Never connect the sensor direct to the ESP8266, sensor high level is 5V
+// ADC of ESP8266 high level is 3.3
+// To connect use a voltage divisor, where 5V will 3v3 on the middle point like
+// this {{URL}}
+
+/*
+  MQUnifiedsensor Library - reading an MQSensor using ESP8266 board
+
+  For this example wi will demonstrates the use a MQ3 sensor.
+  Library originally added 01 may 2019
+  by Miguel A Califa, Yersson Carrillo, Ghiordy Contreras, Mario Rodriguez
+ 
+  Added ESP8266 example 
+  29.03.2020
+  Wiring:
+  https://github.com/miguel5612/MQSensorsLib_Docs/blob/master/static/img/MQ_ESP8266.PNG
+
+ This example code is in the public domain.
+
+*/
+
+//Include the library
+#include <MQUnifiedsensor.h>
+/************************Hardware Related Macros************************************/
+#define         Board                   ("ESP-32") // Wemos ESP-32 or other board, whatever have ESP32 core.
+#define         Pin                     (25)  //IO25 for your ESP32 WeMos Board, pinout here: https://i.pinimg.com/originals/66/9a/61/669a618d9435c702f4b67e12c40a11b8.jpg
+/***********************Software Related Macros************************************/
+#define         Type                    ("MQ-3") //MQ3 or other MQ Sensor, if change this verify your a and b values.
+#define         Voltage_Resolution      (3.3) // 3V3 <- IMPORTANT. Source: https://randomnerdtutorials.com/esp32-adc-analog-read-arduino-ide/
+#define         ADC_Bit_Resolution      (12) // ESP-32 bit resolution. Source: https://randomnerdtutorials.com/esp32-adc-analog-read-arduino-ide/
+#define         RatioMQ3CleanAir        (60) // Ratio of your sensor, for this example an MQ-3
+/*****************************Globals***********************************************/
+MQUnifiedsensor MQ3(Board, Voltage_Resolution, ADC_Bit_Resolution, Pin, Type);
+/*****************************Globals***********************************************/
+
+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
+  MQ3.setRegressionMethod(1); //_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
+  */
+
+  /*****************************  MQ Init ********************************************/ 
+  //Remarks: Configure the pin of arduino as input.
+  /************************************************************************************/ 
+  MQ3.init(); 
+ 
+  /* 
+    //If the RL value is different from 10K please assign your RL value with the following method:
+    MQ3.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 ++)
+  {
+    MQ3.update(); // Update data, the arduino will be read the voltage on the analog pin
+    calcR0 += MQ3.calibrate(RatioMQ3CleanAir);
+    Serial.print(".");
+  }
+  MQ3.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 ********************************************/ 
+  MQ3.serialDebug(true);
+}
+
+void loop() {
+  MQ3.update(); // Update data, the arduino will be read the voltage on the analog pin
+  MQ3.readSensor(); // Sensor will read PPM concentration using the model and a and b values setted before or in the setup
+  MQ3.serialDebug(); // Will print the table on the serial port
+  delay(500); //Sampling frequency
+}

examples/ESP8266/ESP8266.ino

@@ -23,12 +23,12 @@
 //Include the library
 #include <MQUnifiedsensor.h>
 /************************Hardware Related Macros************************************/
-#define         Board                   ("Arduino UNO")
+#define         Board                   ("ESP8266")
 #define         Pin                     (A0)  //Analog input 3 of your arduino
 /***********************Software Related Macros************************************/
 #define         Type                    ("MQ-3") //MQ3
 #define         Voltage_Resolution      (3.3) // 3V3 <- IMPORTANT
-#define         ADC_Bit_Resolution      (10) // For arduino UNO/MEGA/NANO
+#define         ADC_Bit_Resolution      (10) // For ESP8266
 #define         RatioMQ3CleanAir        (60)
 /*****************************Globals***********************************************/
 MQUnifiedsensor MQ3(Board, Voltage_Resolution, ADC_Bit_Resolution, Pin, Type);

library.properties

@@ -1,5 +1,5 @@
 name=MQUnifiedsensor
-version=2.0
+version=2.0.1
 author= Miguel Califa <miguelangel5612@gmail.com>, Yersson Carrillo<miguelangel5612@gmail.com>, Ghiordy Contreras<miguelangel5612@gmail.com>
 maintainer= Miguel Califa <miguelangel5612@gmail.com>
 sentence= This library allows you to read the MQ sensors very easily.

src/MQUnifiedsensor.cpp

@@ -27,7 +27,7 @@ void MQUnifiedsensor::setRL(float RL) {
 }
 void MQUnifiedsensor::setADC(int value)
 {
-  this-> _sensor_volt = (value) * _VOLT_RESOLUTION / (pow(2, ADC_RESOLUTION) - 1); 
+  this-> _sensor_volt = (value) * _VOLT_RESOLUTION / ((pow(2, _ADC_Bit_Resolution)) - 1); 
   this-> _adc =  value;
 }
 void MQUnifiedsensor::setVoltResolution(float voltage_resolution)
@@ -95,7 +95,7 @@ void MQUnifiedsensor::serialDebug(bool onSetup)
     }
     else
     {
-      Serial.print("|"); Serial.print(_adc);  Serial.print("| v = ADC*"); Serial.print(_VOLT_RESOLUTION); Serial.print("/"); Serial.print(pow(2, _ADC_Bit_Resolution)); Serial.print("  |    "); Serial.print(_sensor_volt);
+      Serial.print("|"); Serial.print(_adc);  Serial.print("| v = ADC*"); Serial.print(_VOLT_RESOLUTION); Serial.print("/"); Serial.print((pow(2, _ADC_Bit_Resolution)) - 1); Serial.print("  |    "); Serial.print(_sensor_volt);
       Serial.print("     | RS = ((" ); Serial.print(_VOLT_RESOLUTION ); Serial.print("*RL)/Voltage) - RL|      "); Serial.print(_RS_Calc); Serial.print("     | Ratio = RS/R0|    ");
       Serial.print(_ratio);  Serial.print( "       |   ");
       if(_regressionMethod == 1) Serial.print("ratio*a + b");
@@ -174,7 +174,7 @@ float MQUnifiedsensor::getVoltage(int read) {
       avg += _adc;
       delay(retry_interval);
     }
-    voltage = (avg/ retries) * _VOLT_RESOLUTION / (pow(2, ADC_RESOLUTION) - 1);
+    voltage = (avg/ retries) * _VOLT_RESOLUTION / ((pow(2, _ADC_Bit_Resolution)) - 1);
   }
   else
   {