MQ135 Air Quality Control Gas Sensor

Pin No:

Pin Name:

Description

For Module

1

Vcc

Used to power the sensor, Generally 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 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 the Supply voltage.

3

B-Pins

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

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