Sensitive material of MQ-2 gas sensor is SnO2, which with lower conductivity in MQ-2 gas sensor has high sensitity to LPG, Propane and Hydrogen, also. The MQ-2 Gas Sensor module detects gas leakage in home and industry. The MQ series of gas sensors use a small heater inside with an. In this tutorial, we will learn how to detect Smoke and inflammable gases using an MQ-2 sensor.


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Working Principle The MQ2 has mq2 smoke sensor electrochemical sensor, which changes its resistance for different concentrations of varied gasses. The sensor is connected in series with a variable resistor to form a voltage divider circuit Fig 1and the variable resistor is used to change sensitivity.


The change in the resistance changes the voltage across the sensor, and this voltage can be read by a mq2 smoke sensor. The sensor has different sensitivity for different types of gasses.


The sensitivity characteristic curve Fig 2 is shown below for the different type of gasses. Ro is the resistance of the sensor in clean air 2.

Rs is the resistance of sensor when exposed to gasses Procedure to Calculate the Concentration of a Particular Type of Gas To find the concentration of gas, two values has to be measured using a microcontroller with ADC such as Arduino, 1.

Ro — The resistance of the sensor when measured in clean air, 2. Rs — The resistance of the sensor when it is exposed to any of the mentioned gasses To find Ro, connect the sensor to one of the Analog pins of Mq2 smoke sensor, note values, and select the median value.

This will reduce if any dynamic errors present mq2 smoke sensor the values.

Smoke Detection using MQ-2 Gas Sensor - Arduino Project Hub

The sensor is connected in the series with a mq2 smoke sensor resistor Potentiometer on the sensor board. So, to find the resistance of the sensor Ro or Rsthe resistance of the variable resistor R1 is required.

These sensors can either be purchased as a module or as just the sensor alone.

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If you are trying to only detect not measuring ppm the mq2 smoke sensor of a gas then you can buy it as a module since it comes with an op-amp comparator and a digital out pin. But if you planning to measure the ppm of a gas it is recommended to buy the sensor alone without module.

MQ2 Gas Sensor

Where to use MQ-2 Gas sensor: The module version of this sensor comes with a Digital Pin which mq2 smoke sensor this mq2 smoke sensor to operate even without a microcontroller and that comes in handy when you are only trying to detect one particular gas.

When it comes to measuring the gas in ppm the analog pin has to be used, the analog pin also TTL driven and works on 5V and hence can be used with most common microcontrollers.

So if you are looking for a sensor to detect or measure gasses like LPG, Mq2 smoke sensor, Propane, Hydrogen, CO and even methane with or without a microcontroller then this sensor might be the right choice for you.

How to use MQ-2 Sensors mq2 smoke sensor detect gas: Using an MQ sensor it detects a gas is very easy.


You can either use the digital pin or the analog pin to accomplish this. Simply power the module with 5V and you should notice the power LED on the module to glow and when no gas it detected the output LED will remain turned off meaning the digital output pin will be mq2 smoke sensor.

Remember that these sensors have to be kept on for pre-heating time mentioned in features above before mq2 smoke sensor can actually work with it.

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