MQ-2 Combustible Gas, Smoke Sensor Module

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An Overview about MQ-2 Sensor

The MQ-2 smoke sensor is the metal oxide semiconductor sensor. Hence, also recognized as a Chemiresistor. The MQ2 sensor can quickly detect Alcohol, propane, LPG, hydrogen, and methane. The operating voltage of the sensor is about 5V. Since it requires a warm-up, therefore, it has a preheat duration of 20 seconds. We can use it both as a digital or analog sensor. The sensor is compact and simple to access.

Internal Structure of MQ-2 sensor

They enclose the sensor in two layers of fine stainless steel mesh which is known as an Anti-explosion network. It assures that the heater element inside the sensor will not cause an explosion. The sensing element forms the star-shaped structure. Six connecting legs expand beyond the Bakelite base. From those six legs, two leads heat the sensing element and are connected through the well-known collective alloy called Nickel-Chromium coil. The remaining four legs are actually responsible for output signals. They made the sensing element from Aluminum Oxide (AL2O3) and have a coating of Tin Dioxide (SnO2), which is sensitive to combustible gases.

Working Principle of MQ-2

The working principle of the MQ-2 sensor is based on the resistor. When it detects smoke or fire, the value of its resistance changes. That’s how the gas or smoke gets detected. The sensor works on a very low voltage of around 5Volts. The given potentiometer can change the sensitivity of the digital pin, it draws a current of 500mA.

Features of MQ-2 Sensor

  • Operating Voltage is +5V
  • Can Measure or detect LPG, Alcohol, Propane, Hydrogen, CO and even methane
  • Analog output voltage: 0V to 5V
  • Digital Output Voltage: 0V or 5V (TTL Logic)
  • Preheat duration 20 seconds
  • Can be used as a Digital or analog sensor
  • It can vary the Sensitivity of Digital pin using the potentiometer
  • Wide detecting Scope
  • Fast response and High sensitivity
  • Stable and long life Simple drive circuit

Pinout of MQ-2 Sensor

Pin NamePin NumberDescription
Vcc1Power Pin requires an operating voltage of 5V.
GND2Ground pin.
DO3Digital out the pin, to get the digital output from the sensor.
AO4Analog out the pin. It based the output of this pin on the intensity of the gas.

Applications

Air Quality Monitor

Air Quality Monitoring analyzes multiple environmental parameters of the surroundings and therefore is the brilliant solution for controlling the specific smoke gases. It uses the MQ-2 sensor and is thus great to detect methane, Alcohol, Smoke, and Propane.

Gas Leak Alarm

The goal of detecting a gas leak is to prevent the worst potential causes of the gas leak, using the above-mentioned type of MQ sensor. The choice of the MQ-2 sensor is because of the nature of MQ-2 which is suitable for detecting combustible gases and smoke. Also, it is simple integration with other IoT elements.