ESP8266 Community Forum

- Thu Sep 03, 2015 5:58 am #27704 Hi,
any one now,how to use MQ2 sensor.

Thanks

- Thu Sep 03, 2015 12:21 pm #27723 MQ-X sensors are comparator driven sensors with a 0-5 analogue output that would need to be equalised to the 0-1 volt for use.

The simple solution for the ESP is the Digital output that will toggle at the level set by the small trimmer pot.......this is using a pushbutton but could just as easily trigger from the MQ-3 that I have used....

Code: Select all 
  //
  // Check button for email trigger
  //
  int button = 0;         // variable for reading the pushbutton status
    pinMode(0, INPUT);
    button = digitalRead(0);  // read the state of the pushbutton on gpio 0
  if (button == LOW) {
   emailbutton = "Send";
//LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Email Button....");
  lcd.setCursor(0, 1);
  lcd.print("......Pressed!!!");
  }


- Tue Sep 08, 2015 4:00 pm #28652 Hi,

I have successfully used a MQ-3 sensor with the following setup :

MQ3.png

as you can see I have a voltage divider composed of R9 and R8 resistors to output a 0 to 1V voltage to the ADC

Note also that I have added a mosfet to switch On/Off the heater with GPO2 as a command signal

JP

You do not have the required permissions to view the files attached to this post.