Description: MQ-4 Methane Gas Sensor Module

This is a very easy to use low cost semiconductor Gas sensor Module with analog and digital output. This module uses MQ4 Methane gas sensor as a gas sensing element. It requires no external components just plug in Vcc & ground pins and you are ready to go.For Digital output the threshold value can be easily set by an on-board potentiometer. Using this module you can easily interface MQ4 Methane (CNG) gas Sensor to any Microcontroller, Arduino or even Raspberry Pi.Since this Gas Sensor module is sensitive to Methane it is also small sensitivity to alcohol & smoke.

Specifications:

• Sensor Type Semiconductor
• Power requirements: VCC – 5V±0.1
• DO output: TTL digital 0 and 1 (0.1 and 5V)
• AO output: 0.1-0 .3 V (relative to pollution), the maximum concentration of a voltage of about 4V
• Detection Gas: Natural gas/Methane
• Detection Concentration: 200-10000ppm (Natural gas / Methane)
• Interface: 1 TTL compatible input (HSW), 1 TTL compatible output (ALR)
• Heater consumption: less than 750mw
• Operating temperature: 14 to 122 °F (-10 to 50°C)
• RH Related humidity less than 95%Rh
• O2 Oxygen concentration is 21% (standard condition) – Oxygen concentration can affect sensitivity
• Load resistance: 20KΩ
• Sensing Resistance Rs: 10KΩ- 60KΩ (1000ppm CH4)
• Preheat time:Over 24 hour
• Standard Encapsulation Bakelite, Metal cap

Features:

• Good sensitivity to Combustible gas in wide range
• High sensitivity to CH4, Natural gas.
• Small sensitivity to alcohol, smoke.
• Fast response Stable and long life
• Simple drive circuit

The instruction of Wiring:

1. VCC positive power supply (5V)2. GND power supply is negative3. DO TTL switching signal output4. AO analog signal output

Electrical Performance:

Dection of gas: Natural gas/Methane

Dection of Concentration:300-10000ppm

Input voltage: DC5V

Power consumption (current): 150mA

DO output: TTL digital quantities 0 and 1 (0.1 and 5V)

AO output: 0.1-0.3V (relatively non-polluting), the highest concentration voltage is about 4V

Using the chip: AT89S52

Crystal: 11.0592MHZ

Baud rate: 9600

Compilation environment: Keil

Applications:

• Domestic gas leakage detector
• Industrial Combustible gas detector
• Portable gas detector
• Gas leak alarm, Gas detector

MQ-4 Equivalent Sensors:

MQ-214 (Methane, Natural Gas Detection), MQ306A (LPG Detection), MQ-5 (Natural gas, LPG), MQ306A (LPG detection),MQ-2

MQ-4 Gas Sensor Brief Detail:

MQ-4 Sensor is highly sensitive to Methane – CH4.

Structure and configuration ofMQ-4 gas sensoris shown in above figure (Configuration A or B), sensor composed by micro AL2O3ceramic tube, Tin Dioxide (SnO2) sensitive layer, measuring electrode and heater are fixed into a crust made by plastic and stainless steel net. The heater provides necessary work conditions for work of sensitive components. The enveloped MQ-4 have 6 pin ,4 of them are used to fetch signals, and other 2 are used for providing heating current.

How to Use MQ-4 Sensor Module?

The connections of MQ4Gas Sensor Module are very simple. They are made as follows:

• VCC to 5V
• GND to GND
• AO to AnalogO
• DO to DigitalO

Using a MQ sensor and detecting the gasis quite 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 is 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 gasand you should see the output LED to go high along with the digital pin. 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 detect the gas. 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.

Sensitivity Adjustment:

Resistance value of MQ-4 is difference to various kinds and various concentration gases. So while using this component, sensitivity adjustment is very necessary. It isrecommended tocalibrate the sensor for 5000ppm of CH4concentration in air and use value of Load resistance (RL) about 20KΩ(10KΩ to 47KΩ). When accurately measuring, the proper alarm point for the gas detector should be determined after considering the temperature and humidity influence. For more information, read theMQ-4 datasheetattached at the end of this article.

MQ-4 Sensor 2D Model (Configuration A and B)

Documents:

MQ-4 Methane Gas Sensor Datasheet

Package Included:

1 x MQ-4 Gas Sensor Module

• Using high-quality dual-panel design, with power indicator and TTL signal output instructions ;
• The switching signal having a DO (TTL) output and analog output AO ;
• TTL output valid signal is low . ( Low-level signal when the output light can be directly connected to the microcontroller or relay module )
• The higher the voltage , the concentration of the analog output voltage is higher.
• For methane, natural gas has a good detection sensitivity.
• There are four screw holes for easy positioning ;
• Dimensions : 32 (L) * 20 (W) * 22 (H)
• Rapid response and recovery characteristics