MQ6-Gas Sensor | Code | Circuit | Pin configuration

MQ6-GAS SENSOR

MQ6-Gas Sensor is a device normally used to detect specific gases. As a human we can smell up to 400 different types of gases, like that Gas Sensors can detect the specific gases, so we can say that gas sensor is an Electronic-Nose that used to detect the smell or gases. The MQ6-gas sensor is designed to detect LPG gas, Iso-butane, Propane, or any type of flammable gas.

Model number: MQ6

MQ6 stands for

Mq- Name of the sensor

6- Identifies the type of gases (butane, LPG-gas)

Other names: Gas sensor, LPG-Gas sensor, Flammable Gas sensor 

Other  related devices: MQ2, MQ3, MQ6

 

MQ-6 SENSOR

MQ6-Gas Sensor Pin configuration

MQ6-Gas Sensor

A	Input/output
B	Input/output
H	Heating Coil

 

MQ-6 Gas Sensor Pinout

NOTE: A, B pins are reversible that means any of these two pins can be used as input or output.

 

MQ6-Gas Sensor Module

 

Vcc	Supply positive terminal
Gnd	Supply ground Terminal
A0	Analog output
D0	Digital output

MQ-6 Gas Sensor Pinout

 

NOTE: MQ6-Gas Sensor module has an inbuilt comparator circuit that forms A,H,B pins to Vcc,Gnd, A0, D0 pins

 

MQ6-Gas Sensor Technical specifications

Model	MQ6
Sensor Type	Semiconductor
Target gas	LPG, Butane, Propane
Detection range	300 to 10000ppm
Operating Voltage(Vc)	≤ 25v DC
Heating Voltage(Vh)	5v±0.1v AC/DC

 

 

Other models of Gas sensors

List of Gas sensors

MQ2	Methane, Butane, LPG, Smoke
MQ3	Alcohol, Ethanol, Smoke
MQ4	Methane, CNG Gas
MQ5	Natural gas, LPG
MQ7	Carbon Monoxide
MQ8	Hydrogen Gas
MQ9	Carbon Monoxide, flammable gasses
MQ131	Ozone
MQ135	Air Quality
MQ136	Air Quality
MQ137	Ammonia
MQ138	Benzene, Toluene, Alcohol, Propane
MQ214	Methane, Natural Gas
MQ216	Natural gas, Coal Gas
MQ303A	Natural gas, Coal Gas
MQ306A	LPG, butane
MQ307A	Carbon Monoxide
MQ309A	Carbon Monoxide

  

Note: The output voltage of the any type of sensor will depend on the internal resistance of the sensing element.

GAS-SENSOR-TEST-CIRCUIT

MQ6-Gas sensor working

MQ6-Gas sensors detect the concentration of gases in the atmosphere, based on the gas concentration the potential difference across the gas sensor will vary by changing internal the resistance of the sensing element.

GAS SENSOR SCHEMATIC

After the giving power supply, we know that the voltage will change corresponding to its resistance. Based on this phenomenon the internal resistance of the sensing element in the gas the sensor  will depend on the input gas concentration, for example, the amount of the input gas concentration will increases then internal resistance of the sensing element will decrease, so the output voltage gradually increases.

GAS SENSOR OUTPUT

NOTE: Internal the resistance of the gas sensor depends on the inbuilt sensing element

MQ6-Gas sensor Sensing element Working

 The MQ6-Gas sensor is composed of Micro AL2O3 ceramic tube, Tin Dioxide(SNO2) sensitivity layer, Measuring Electrode, heating coil.

The ability to sense the element will depend on the manufacturing material. Generally Gas sensors sensing material is designed by using a chemiresister to change the resistivity. Chemiresister is Tin Dioxide(Sno2), it is N-type semiconductor so it contains free electrons to donate(donor).When you energized the device oxygen particles in the atmosphere/air  will attracts the electrons, so the electrons move towards the surface of the gas sensors then the conductivity is very less(high resistance), whenever the MQ6-gas sensor identifies the LPG gas/butane then free electrons come back to their original state, so conductive is high(low resistance). There is a chemical bond between the atmospheric gases and electrons of the gas sensor, here we noticed that internal current flow will be controlled by atmospheric gases(input gas concentration)

 

How MQ6-gas sensors are modeled

Gas sensors are available in two types of packages one is Gas sensor module and the other is Gas sensor device. If we want to use the Gas sensor in any circuit design you have to make connections or interface that requires the pin configuration of the MQ6-Gas sensor, let’s look into the pin configuration of the Gas sensor.

MQ6-Gas sensor Module: 4-Pins

1.Vcc (positive terminal supply)

2.Gnd(negative terminal supply)

3.D0 (Digital Output)

4.A0 (analog output)

 

MQ6-Gas sensor Device: 6-Pins

A,H,A,B,H,B. It required some external circuitry to interface in any design

From the above discussion we can say that Gas sensor Module is very easy to interface in any design circuits, but the MQ6-Gas sensor device needs some extra circuit to the interface.

 

MQ6-GAS SENSOR

 

How to use MQ6-Gas sensor

Gas sensor module:

Gas sensor module has 4 pins such as Vcc,Gnd,A0,D0 as discussed above.

1.Vcc is connected to the battery positive terminal

2. Gnd is connected to the battery negative terminal

3. D0 is connected to the output device.

4. A0 No connection

Note: Here we are using only Digital output(D0).

 

MQ6-Gas-sensor-circuit

 

Circuit working: When the MQ6-gas sensor detects the LPG gas, then it sends LOGIC-HIGH signal to turn ON the buzzer.

When the MQ6-gas sensor detects the NO gas, then it sends LOGIC-LOW signal to turn OFF the buzzer.

Gas sensor Device

It requires some external circuitry,

1.LM393

2.Potentiometer

 

MQ6-Gas-sensor-circuit

 

Circuit working: Here MQ6-Gas sensor signal will send to the comparator circuit, so this circuit triggers the buzzer either ON state or OFF state.

When the MQ6-gas sensor detects the LPG gas the internal resistance will starts decreasing/increasing, so The MQ6-Gas sensor output signal will exceed the threshold limit of the comparator then the comparator turn ON the buzzer otherwise comparator turns OFF the buzzer.

 

How to use MQ6-Gas sensor to measure PPM | How to interface MQ6-Gas sensor with Arduino

Circuit diagram

 

MQ6 GAS SENSOR -ARDUINO-CIRCUIT

Code

/***************************************************** # MQ-6 Gas sensor Example sketch follow us: www.technoelectronics44.com ******************************************************/ #include<SoftwareSerial.h> #define gas A0 void setup() { Serial.begin(9600); pinMode(gas,INPUT); Serial.print("Welcome to TechnoElectronics44"); Serial.println("GAS:"); } void loop() { Serial.print(analogRead(A0)); Serial.print("PPM"); Serial.println(); delay(500); }  

Output

MQ6-GAS SENSOR OUTPUT WINDOW

 Applications of Gas sensors

• High sensitivity to LPG gas detection
• Cigarette smoke detection
• Alcohol detection
• Butane gas detection
• Propane gas detection
• Cooking fumes

 

Datasheet

 

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