Trying to read different gas levels with MQ2 Gas Sensor

Question

I found a link on how to connect MQ-2 Gas Sensor to Arduino Uno.

http://electronicsprojectshub.com/how-to-connect-mq2-gas-sensor-to-arduino/

After I bought all the parts and tried it out, the sensor gave me this in the serial monitor

Ro: 10.81 kohm

LPG:0.00ppm CO:0.00ppm SMOKE:0.00ppm

LPG:0.00ppm CO:0.00ppm SMOKE:0.00ppm

and so on.

Here is the code I used

#include <MQ2.h>
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16,2);
int Analog_Input = A0;
int lpg, co, smoke;
MQ2 mq2(Analog_Input);
void setup(){
 pinMode(A0, INPUT);
 Serial.begin(9600);
 lcd.begin();
 lcd.backlight();
 mq2.begin();
}
void loop(){
 float* values= mq2.read(true);
 //lpg = values[0];
 lpg = mq2.readLPG();
 //co = values[1];
 co = mq2.readCO();
 //smoke = values[2];
 smoke = mq2.readSmoke();
 lcd.setCursor(0,0);
 lcd.print("LPG:");
 lcd.print(lpg);
 lcd.print(" CO:");
 lcd.print(co);
 lcd.setCursor(0,1);
 lcd.print("SMOKE:");
 lcd.print(smoke);
 lcd.print(" PPM");
 delay(1000);
}

Please help me fix it so that it can perform just the same as the video. Thanks.

• charlotte: I want it to show this LPG: 4 CO:2803 SMOKE: 16 PPM on the LCD. Please help. Thanks.
• jsotola: blow the right amount of gas and smoke onto the sensor so that you get those readings

Answer 1

First this should be like this:

float* values= mq2.read(false); //false

and then write this to be printed in the serial monitor

Serial.print('\n');
 Serial.print("LPG:");
 Serial.print(lpg);
 Serial.print(" CO:");
 Serial.print(co);
 Serial.print('\n');
 Serial.print("SMOKE:");
 Serial.print(smoke);
 Serial.print(" PPM");
 Serial.print('\n');