By this Arduino project you can display the amount of LPG and methane gas leakage on 16x2 LCD display. I set the program to run the buzzer when the value become 15 or more, you can change this level. you have to use 150 to 220 ohm resistor to protect the backlight LED of display. Parts list: LCD display 16x2 buzzer Resistor 220 ohm MQ-4 gas sensor module Potentiometer 1K Connecting wires Arduino board #include <LiquidCrystal.h> LiquidCrystal lcd(7, 8, 9, 10, 11, 12); int potPin = A4; int potValue = 0; int buzzer = 6; void setup() { lcd.begin(16, 2); // lcd rows and columns lcd.print("GAS SENSOR"); pinMode(6, OUTPUT); } void loop() { potValue = analogRead(potPin); lcd.setCursor(0, 1); lcd.print("Value = "); lcd.print(potValue); delay(1000); lcd.print(" "); delay(1); if (potVal...