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Smoke Detection using MQ-2 Gas Sensor

September 29, 2022 by CIRCUITS DIY

In this Tutorial, We are Going To Make Smoke Detection using MQ-2 Gas Sensor


Hardware Table

Circuit Diagram

Working Explanation

The MQ-2 smoke sensor is sensitive to smoke and to the following flammable gases:

  • LPG
  • Butane
  • Propane
  • Methane
  • Alcohol
  • Hydrogen

The resistance of the sensor is different depending on the type of gas.

The smoke sensor has a built-in potentiometer that allows you to adjust the sensor sensitivity according to how accurately you want to detect gas.

The voltage that the sensor outputs changes accordingly to the smoke/gas level that exists in the atmosphere. The sensor outputs a voltage that is proportional to the concentration of smoke/gas.

In other words, the relationship between voltage and gas concentration is the following:

  • The greater the gas concentration, the greater the output voltage
  • The lower the gas concentration, the lower the output voltage

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