Published May 22, 2021 © LGPL

Gas Ananlyser Using Arduino

Analyser The Atmospheric Gas Using MQ Sensors & Arduino

IntermediateFull instructions provided4,455

Things used in this project

Hardware components

Arduino Nano R3

Seeed Studio Grove - Gas Sensor(MQ2)

DFRobot Gravity: Analog CH4 Gas Sensor (MQ4) For Arduino

DFRobot Gravity: Analog LPG Gas Sensor (MQ5) For Arduino

Adafruit MQ-135 Air Quality Sensor

DHT11 Temperature & Humidity Sensor (4 pins)

DFRobot I2C 16x2 Arduino LCD Display Module

Breadboard (generic)

Male/Female Jumper Wires

Male/Male Jumper Wires

Digilent 5V 2.5A Switching Power Supply

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Hot glue gun (generic)

Story

This Is An AtmosphericGasAnanlyser Using MQ Series Sensors, Dht-11 Sensor & Arduino The Basic Idea Is To Precisely Measure Data Using Sensors Analog Read & Display It In I2CLcd, Here The Sensors Can Give Values Of LPG, CNG, HYDROGEN, AIR-QUALITY This Project Can Be Used To Collect Sensor Readings For FutureResearchProcesses. If You Need You Can Simply Add An SD Card To Store The Data As String And Collect The Readings, Here For Simplicity & SpaceReduction Iam Using Arduino Nano And I2ClCD Display, For My Ease. The Sensors Spit Out Aanalog Readings And I Have Converted It Into Useful PPM Values Of The Sensors analogToPPM(analogRead(The Sensor)). It Is Very Useful So I Have Converted It To PPM, If You Like What I Do Little Support To My Youtube Channel Would Be Appreciative

Code

Arduino Code

/*feel free to contact
 * sreeramaj53@gmail.com
 * www.youtube.com/ZenoModiff
 * last updated - time 09:05 PM - date 20 may 2021
 * Github Link :-- https://github.com/Zenomodiff/Atmospheric-Gas-Ananlyser-With-MQ-Series-Sensors-Dht-11
 */

#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
#include "DHT.h"
#define DHTPIN 13     
#define DHTTYPE DHT11 

DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal_I2C lcd(0x27, 16, 2);

const int mq2 = A0;
const int mq4 = A1;  
const int mq5 = A2; 
const int mq135 = A3;

float m = -0.6527; 
float b = 1.30; 
float R0 = 21.91;

void setup() {

  lcd.begin();
  lcd.backlight();
  lcd.print("Atmosphere");
  lcd.setCursor(0,3);
  lcd.print("Gas Analyser");
  delay (3000);
  lcd.clear();

  lcd.print("By");
  lcd.setCursor(0,3);
  lcd.print("Zeno Modiff");
  delay (3000);
  lcd.clear();

  pinMode(mq4, INPUT); 
  pinMode(mq135, INPUT); 
  pinMode(mq5, INPUT); 
  pinMode(mq2, INPUT); 
  
  Serial.begin(9600);
  dht.begin();
}

void loop() {
  
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  float f = dht.readTemperature(true);
  if (isnan(h) || isnan(t) || isnan(f)) {
  Serial.println(F("Failed to read from DHT sensor!"));
  return;
  float hif = dht.computeHeatIndex(f, h);
  float hic = dht.computeHeatIndex(t, h, false);
  }
  double mq4_value = analogToPPM(analogRead(mq4));
  double mq135_value = analogToPPM(analogRead(mq135));
  double mq5_value = analogToPPM(analogRead(mq5));
  double mq2_value = analogToPPM(analogRead(mq2));
  
  Serial.println("************************************");
  Serial.print("MQ-4 Value: ");Serial.print(mq4_value, DEC);Serial.println(" PPM");
  Serial.print("MQ-135 Value: ");Serial.print(mq135_value, DEC);Serial.println(" PPM");
  Serial.print("MQ-5 Value: ");Serial.print(mq5_value, DEC);Serial.println(" PPM");
  Serial.print("MQ-2 Value: ");Serial.print(mq2_value, DEC);Serial.println(" PPM");
  Serial.print("DHT-Temp: ");Serial.print(t);Serial.println(" c");
  Serial.print("DHT-Humi: ");Serial.print(h);Serial.println(" %");
  Serial.println("************************************\n\n");

  lcd.setCursor(0,0);
  lcd.print("CNG Value");
  lcd.setCursor(0,3);
  lcd.println(mq4_value);
  lcd.setCursor(7,7);
  lcd.print("PPM");
  delay(3000);
  lcd.clear();

  lcd.setCursor(0,0);
  lcd.print("AQI Value");
  lcd.setCursor(0,3);
  lcd.println(mq135_value);
  lcd.setCursor(7,7);
  lcd.print("PPM");
  delay(3000);
  lcd.clear();

  lcd.setCursor(0,0);
  lcd.print("LNG");
  lcd.setCursor(0,3);
  lcd.println(mq5_value);
  lcd.setCursor(7,7);
  lcd.print("PPM");
  delay(3000);
  lcd.clear();

  lcd.setCursor(0,0);
  lcd.print("SMOKE");
  lcd.setCursor(0,3);
  lcd.println(mq2_value);
  lcd.setCursor(7,7);
  lcd.print("PPM");
  delay(3000);
  lcd.clear();

  lcd.setCursor(0,0);
  lcd.print("DHT-11");
  lcd.setCursor(0,3);
  lcd.print("Temp -");
  lcd.setCursor(7,4);
  lcd.println(t);
  delay(3000);
  lcd.clear();

  lcd.setCursor(0,0);
  lcd.print("DHT-11");
  lcd.setCursor(0,3);
  lcd.print("Humi -");
  lcd.setCursor(7,4);
  lcd.println(h);
  delay(3000);
  lcd.clear();

}
  double analogToPPM(int aValue) {
  float sensor_volt;
  float RS_gas; 
  float ratio;
  int sensorValue = aValue;

  sensor_volt = sensorValue*(5.0/1023.0); 
  RS_gas = ((5.0*10.0)/sensor_volt)-10.0; 
  ratio = RS_gas/R0; 
  double ppm_log = (log10(ratio)-b)/m;
  return ppm_log;
}