MQ-2 Gas Sensor Module | Detects Smoke, LPG & Butane | For Arduino Projects

This MQ gas sensor module lets you add gas detection to your Arduino or ESP32 projects. Each module focuses on certain gases. This gives you a specific tool for what you need. It works by checking how much its electrical resistance changes. Features and Benefits - Many sensor types - Pick the right sensor. For example, MQ-2 for smoke, MQ-3 for alcohol, or MQ-7 for carbon monoxide. - Both analog and digital outputs - Use the analog pin for a changing reading. Use the digital pin for a simple on/off alert. - Built-in sensitivity knob - A small dial lets you set the exact gas level for the digital alert. - Runs on 5V - It connects directly to the power and input pins of an Arduino Uno and similar microcontrollers. Applications - Air Quality Projects - The MQ-135 air quality sensor can find ammonia, benzene, and smoke. This helps check indoor air. - Safety Alarms - Build a gas leak alarm with an MQ-9 sensor. It detects carbon monoxide and flammable gases like LPG. - Hobby Electronics - Wire up an MQ-3 alcohol sensor module. You can make a personal breathalyzer or other interactive items. What You Need To test a gas sensor, such as this MQ-2 Gas Sensor Module, you will need a multimeter capable of measuring microamperes ($\mu\text{A}$). For safety, ensure you have appropriate personal protective equipment, including work gloves. A wiring diagram for your specific Arduino project will also be beneficial for understanding the circuit layout. This module is a resistance sensor, which detects gases like smoke, LPG, and butane by changes in electrical resistance. Understanding how electrochemical gas sensors work involves detecting gas concentration via chemical reactions that produce a measurable electrical signal. Method 1: Testing Active Signal Strength ($\mu\text{A}$) This method helps determine if your gas sensor is actively responding to the presence of detected gases. While the MQ-2 is a general gas sensor and not a flame sensor found in a gas furnace, the principle of testing electrical current remains similar. A flame sensor on a gas furnace works by detecting the presence of a flame to ensure safe operation. This MQ-2 Gas Sensor Module, designed for Arduino projects, functions as a gas sensor by detecting changes in resistance when exposed to gases such as smoke, LPG, and butane.