From 1924e21e61386c2a7eae167c868e3b168ef7d384 Mon Sep 17 00:00:00 2001
From: miguel5612 <miguelangelcu@ufps.edu.co>
Date: Wed, 29 May 2019 20:41:04 -0500
Subject: [PATCH] Added comments

---
 examples/MQ-2/MQ-2.ino  | 18 ++++++++++++++++--
 src/MQUnifiedsensor.cpp |  3 +--
 src/MQUnifiedsensor.h   |  8 +++++++-
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/examples/MQ-2/MQ-2.ino b/examples/MQ-2/MQ-2.ino
index 9e8aee1..45b5581 100644
--- a/examples/MQ-2/MQ-2.ino
+++ b/examples/MQ-2/MQ-2.ino
@@ -20,18 +20,32 @@
 #define pin A0 //Analog input 0 of your arduino
 #define type 2 //MQ2
 
+/*****************************  MQInicializar****************************************
+  Input:  pin, type 
+  Output:  
+  Remarks: This function create the sensor object.
+  ************************************************************************************/ 
 //Declare Sensor
-
 MQUnifiedsensor MQ2(pin, type);
 
 void setup() {
   //Init serial port
   Serial.begin(115200);
+  /*****************************  MQInicializar****************************************
+  Input:   
+  Output:  
+  Remarks: This function configure the pinMode
+  ************************************************************************************/ 
   //init the sensor
   MQ2.inicializar(); 
 }
 
-void loop() {
+  void loop() {
+  /*****************************  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
   int lecture =  MQ2.readSensor("", true);
   delay(400);
diff --git a/src/MQUnifiedsensor.cpp b/src/MQUnifiedsensor.cpp
index 6593d73..670406c 100644
--- a/src/MQUnifiedsensor.cpp
+++ b/src/MQUnifiedsensor.cpp
@@ -141,8 +141,7 @@ double MQUnifiedsensor::calibrate() {
     float R0; //Define variable for R0
     float sensorValue; //Define variable for analog readings
     sensor_volt = this->getVoltage(); //Convert average to voltage
-    RS_air = (5.0-sensor_volt)/sensor_volt; // omit *RL
-    R0 = RS_air / _ratioInCleanAir; //Calculate R0
+    R0 = sensor_volt / _ratioInCleanAir; //Calculate R0
     return R0;
 }
 double MQUnifiedsensor::getVoltage() {
diff --git a/src/MQUnifiedsensor.h b/src/MQUnifiedsensor.h
index 8f283d3..b034cf8 100644
--- a/src/MQUnifiedsensor.h
+++ b/src/MQUnifiedsensor.h
@@ -7,6 +7,8 @@
 //Count of posible lectures
 #define lecturesAvailable 19
 
+/************************Hardware Related Macros************************************/
+
 //Index in the nameLecture vector
 #define defaultMQ2 "LPG" // LPG
 #define defaultMQ3 "Alcohol" // Alcohol
@@ -21,6 +23,7 @@
 #define defaultMQ303 "Isobutano" //Isobutano
 #define defaultMQ309 "CO" //CO
 
+/*****************************Globals***********************************************/
 #define RatioMQ2CleanAir 1
 #define RatioMQ3CleanAir 2
 #define RatioMQ4CleanAir 3
@@ -34,12 +37,15 @@
 #define RatioMQ303CleanAir 135
 #define RatioMQ309CleanAir 303
 
+/***********************Software Related Macros************************************/
+
 #define ADC_RESOLUTION 10 // for 10bit analog to digital converter.
 #define retries 50
 #define retry_interval 20
 
-//Values consolidated
+/**********************Application Related Macros**********************************/
 /* Gas, Value of m (Slope) and b (Cut on x axis) points */
+//Values consolidated
 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"};