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MQ-6 Gas Sensor

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Pin Configuration

Pin No:

Pin Name:

Description

For MQ6 Sensor Module

1

Vcc

This pin powers the module, typically the operating voltage is +5V

2

Ground

Used to connect the module to system ground

3

Digital Out

You can also use this sensor to get digital output from this pin, by setting a threshold value using the potentiometer

4

Analog Out

This pin outputs 0-5V analog voltage based on the intensity of the gas 

For MQ6 Sensor

1

H -Pins

Out of the two H pins, one pin is connected to supply and the other to ground

2

A-Pins

The A pins and B pins are interchangeable. These pins will be tied to Supply voltage.

3

B-Pins

The A pins and B pins are interchangeable.   One pin will act as output while the other will be pulled to ground.

 

Features of MQ6 Gas sensor

  • Operating Voltage is +5V
  • Can be used to detect LPG or Butane gas
  • 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
  • The Sensitivity of Digital pin can be varied using the potentiometer

 

 

Alternative MQ Gas sensors

Sensor Name

Gas to measure

MQ-2

Methane, Butane, LPG, Smoke

MQ-3

Alcohol, Ethanol, Smoke

MQ-4

Methane, CNG Gas

MQ-5

Natural gas, LPG

MQ-6

LPG, butane

MQ-7

Carbon Monoxide

MQ-8

Hydrogen Gas

MQ-9

Carbon Monoxide, flammable gasses

MQ131

Ozone

MQ135

Air Quality

MQ136

Hydrogen Sulphide gas

MQ137

Ammonia

MQ138

Benzene, Toluene, Alcohol, Propane, Formaldehyde gas, Hydrogen

MQ214

Methane, Natural Gas

MQ216

Natural gas, Coal Gas

MQ303A

Alcohol, Ethanol, smoke

MQ306A

LPG, butane

MQ307A

Carbon Monoxide

MQ309A

Carbon Monoxide, flammable gas

 

MQ6 Equivalent Sensors

MQ-2, MQ-5,AQ-2, MQ-306A, AQ-3

 

Where to use MQ-6 Gas sensor?

The MQ-6 Gas sensor can detect or measure gases like LPG and butane. The MQ-6 sensor module comes with a Digital Pin which makes this 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, or methane with or without a microcontroller then this sensor might be the right choice for you.

 

How to use MQ-6 Sensors to Detect gas?

Using a MQ sensor it detect 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 0V. Remember that these sensors have to be kept on for pre-heating time (mentioned in features above) before you can actually work with it. Now, introduce the sensor to the gas you want to detect and you should see the output LED to go high along with the digital pin, if not use the potentiometer until the output gets high. Now every time your sensor gets introduced to this gas at this particular concentration the digital pin will go high (5V) else will remain low (0V).

You can also use the analog pin to achieve the same thing. Read the analog values (0-5V) using a microcontroller, this value will be directly proportional to the concentration of the gas to which the sensor detects. You can experiment with this values and check how the sensor reacts to different concentration of gas and develop your program accordingly.

 

How to use MQ-6 sensor to measure PPM?

If you are looking for some accuracy with your readings then measuring the PPM would be the best way to go with it. It can also help you to distinguish one gas from another. So to measure PPM you can directly use a module. A basic wiring for the sensor from datasheet is shown below.

MQ-6 Gas Sensor Wiring Diagram

The procedure to measure PPM using MQ sensor is the same but few constant values will vary based on the type of MQ sensor used. Basically we need to look into the (Rs/Ro) VS PPM graph given in the MQ-6 datasheet, and also shown below.

MQ-6 Gas Measurement Graph

The value of Ro is the value of resistance in fresh air and the value of Rs is the value of resistance in Gas concentration. First you should calibrate the sensor by finding the values of Ro in fresh air and then use that value to find Rs using the formulae:

MQ-6 Gas Sensor Rs Value Calculation

Once we calculate Rs and Ro we can find the ratio and then using the graph shown above we can calculate the equivalent value of PPM for that particular gas.

 

Applications

  • Detect or measure Gases like LPG, and butane
  • Air quality monitor
  • Gas leak alarm
  • Safety standard maintenance
  • Maintaining environment standards  in hospitals 

 

2D model of MQ-6 Gas sensor

If you purchased as sensor then you can use the following dimensions to create your own PCB for your application

MQ-6 Gas Sensor Dimensions





Download Datasheet PDF:
MQ-6 Gas Sensor Datasheet