MQ-2 Gas Sensor

Other Hardware Sensors
1

Hi everyone ! ,
In my studies, I have a project where I use the MQ-2 gas sensor.
here is the program I use:

const int analogInPin = A0;  // Analog input pin that the potentiometer is attached to
const int ledPin = 13;                 // LED connected to digital pin 13

int sensorValue = 0; 


void setup() {
  // put your setup code here, to run once:
 Serial.begin(9600); 
  pinMode(ledPin, OUTPUT);      // sets the digital pin as output

}

void loop() {
  // put your main code here, to run repeatedly:
 sensorValue = analogRead(analogInPin);            
  // determine alarm status
  if (sensorValue >= 250)
  {
    digitalWrite(ledPin, HIGH);   // sets the LED on
  }
  else
  {
  digitalWrite(ledPin, LOW);    // sets the LED off
  }

  // print the results to the serial monitor:
  Serial.print("sensor = " );                       
  Serial.println(sensorValue);     
  delay(750);                     
}

the program is to light a LED when the gas rate is greater than 250ppm.

But I have a problem;
that there is an equation for an analog value to a value ppm?

Then datasheet says that this sensor can capture several gas but I have only one value,
Can we have several value display simultaneously?

If someone has an MQ-2 program that works, I'm interested

thank you in advance :slight_smile:

Jeremy

2

Hi, welcome to the forum.

This is some basic information : Arduino Playground - MQGasSensors

3

Bonjour j'ai le même problème que toi pour un de mes collègues il le résout et je te le passe

jean lc

4

Hello,

See discussion here for calibration in open air:

Here are my libraries with curves calculated from datasheets :

The MQ series are very cheap, variable, and change their values in time. It is a good entry point but no more after. Oftern the knob on the pre-assemble boards are only sed for the digital signal and its led on the board.

For H2, I am now considering MIcS sensors.

5

Hello,
Thank you for your reply !

I looked your libraries with curves calculated from datasheets :

But I have the MQ2 gas sensor only; Have you got functional program epierre ?

Jeremy