Hi readers! Welcome to another article where we are discussing the MQ family members. Today, our motto is to learn about the MQ-5 natural liquified petroleum gas (LPG) sensor. The gas sensing material used in this sensor is known as tin dioxide(SnO2). It detects the natural LPG in the surroundings as soon as the core material of this sensor comes in contact with the LPG. This will be explained in simple words in this article.
Today, we’ll start learning about the basic introduction of the MQ-5 natural LPG sensor. After that, we’ll move towards its datasheet element, where we are going to see the specifications and features of the sensor, along with the pinout configuration and internal structure. We’ll also see the working principle and applications of the MQ-5 natural LPG sensor, and all the information will be shown by using tables, descriptions, and images for the best concepts.
So, let’s dive into the first topic to move forward:
The MQ-5 natural LPG sensor belongs to the class of sensors that are used for the detection of different gases. The MQ-5 natural LPG sensor can detect multiple gases with the help of the semiconductor material tin dioxide (SnO2) present in its basic structure. This material has low conductance in pure gas (with no natural LPG), but as soon as it comes into contact with the natural LPG, the electrical conductance decreases, which is indicated through the output pin of this sensor. The simple circuit of this sensor converts this change in conductivity into a voltage change, and as a result, these sensors can send the signal to other components of the circuit to stimulate the system.
Here is a simple list of the detectable gases using an MQ-5 natural LPG sensor:
Before going into the details of its external structure, it is better to know about the internal features and specifications of this product. Here are some important features of the MQ-5 sensor that make it a good choice for natural LPG detection:
The first and most obvious feature of this sensor is, that it is highly sensitive to propane (C3H8); therefore, the primary goal of this sensor is to detect any liquified petroleum gas (LPG).
The internal structure is designed in such a way that it responds to the LPG as soon as the sensitive internal material comes into contact.
It requires simple additional circuitry to create the whole system, and its design is easy to integrate with other components.
It has low power consumption and, therefore, is a suitable component of projects like the Internet of Things (IoT). Here, it can work continuously, and the simple structure is the reason behind its long life.
It provides stable results and readings over time and, therefore, is a reliable component.
Parameter |
Value |
Units |
Sensor Type |
Semiconductor |
N/A |
Standard Encapsulation |
Bakelite, Metal cap |
N/A |
Target Gas |
LPG, CH4 |
N/A |
Detection Range |
300 - 10000 ppm (CH4, C3H8) |
ppm |
Loop Voltage (Vc) |
≤ 24 V |
DC |
Heater Voltage (VH) |
5.0 V ± 0.1 V |
AC or DC |
Load Resistance (RL) |
Adjustable |
N/A |
Heater Resistance (RH) |
26 Ω ± 3 Ω |
(room temp.) |
Heater Consumption (PH) |
≤ 950 mW |
N/A |
Sensitivity (S) |
Rs(in air) / Rs(in 2000 ppm C3H8) ≥ 5 |
N/A |
Output Voltage (Vs) |
2.5 V - 4.0 V |
(in 2000 ppm C3H8) |
Concentration Slope (α) |
≤ 0.6 (R3000ppm/R1000ppm C3H8) |
N/A |
Standard Test Conditions |
||
Temperature (Tem) |
20°C ± 2°C |
N/A |
Humidity |
55% ± 5% RH |
N/A |
Before going into the details of the external structure, let’s have a look at the internal structure of this sensor:
The image shown above displays the structure of the dimension from different angles of the sensor. The unit here is a millimeter, and all the readings have a tolerance:±0.1mm. We’ll learn the detailed dimensions soon in this article.
An important feature of this sensor is its simple circuit, which not only makes it less power-consuming but also allows the user to install it without any complications. Here is the basic structure of this LPG sensor:
The labeling of the image will be clarified in the next section when we study its structure in detail.
If you want to study the datasheet in more detail then I suggest you visit the following link:
Just like most of the gas sensors of this class, MQ-5 has four pins. In some models, the additional two pins are also present. It has a simple structure, and the detail of each pin is given in the table below:
Standard Configuration |
Alternative Configuration |
Function |
A |
AO (Analog Out) |
Analog Output |
H |
H (Heater) |
Heater Power |
GND |
GND (Ground) |
Ground |
VCC |
VCC (Power) |
Power Supply |
N/A |
DO (Digital Out) |
Digital Output (optional) |
N/A |
A (Analog Ground) |
Analog Ground (optional) |
A plus point of this series is, the gas sensors come in different packages so that the user may choose MQ-5 natural LPG sensor according to the type of circuit. Each package has its own pros and cons. Here are some important packages in which this sensor is available:
Package Type |
Description |
Advantages |
Disadvantages |
DIP |
Through-hole mounted |
Simple and affordable |
Not suitable for space-constrained applications |
SMD |
Surface-mount |
Ideal for space-constrained applications |
Requires soldering expertise |
Custom Module |
Pre-assembled module |
Easy to use |
Most expensive |
Some other gas sensors from the MQ series can be used in place of the MQ-5 natural LPG sensor, but these may not be that efficient. Here are some popular gas sensors that can be used in place of MQ-5 natural LPG sensors:
The electronic components are sensitive, and the performance depends on the circuit and the manufacturing features. If you want to get the best MQ-5 natural LPG sensor, you must buy it from the following platforms:
eBay
AliExpress
Amazon
The MQ-5 sensor has a similar working as other gas sensors from the MQ series. The sensor detects LPG and methane gases through the semiconductor metal oxide sensing layer. Here is the breakdown of the work into different steps:
The MQ-5 has a heating element in its core that is constantly powered. Typically, it is done on the 5V and this heating enables the sensing layer to absorb more gas molecules from its surrounding air. Usually, the sensing element is tin dioxide (SnO2) because it is an excellent receptor of flammable gases.
The constant heating allows the reactive material to absorb oxygen and create oxygen ions on its surface. In this way, these ions are readily available for the flammable gases needed for the reaction. As a result, a depletion region is formed around the tin oxide so that the electrical resistance of the circuit increases.
As soon as the reactive gases (LPG) come into contact with the oxygen ions, these start reacting with the liquified petroleum gas. This results in a decreasing number of ions and a decrease in electrical resistance. We know that the electric current is inversely proportional to the resistance so the overall electrical conductivity of the circuit is affected, which causes the sensing of the gas.
The circuit is designed in such a way that the change in the current values stimulates the analog output that can be detected at the analog pin as an output.
Some models of MQ-5 have a digital output as well. The change in the electrical current causes a change in the voltage difference between the diodes of the circuit. This voltage change is detected on the digital pin of the MQ-5 natural LPG sensor. This happens because the circuit has an analog to a digital converter.
The voltage change typically ranges from 2.5V to 4.0V. As the concentration of the LPG and other reactive gases increases, it causes a change in the electrical conductance and as a result, less voltage change is seen.
A feature of this sensor is its small and compatible size, which can fit in different circuits. Here are the dimensions of the MQ-5 natural gas sensor that will help you work with it in a circuit:
Dimension |
Value |
Units |
Diameter |
20 |
mm |
Height |
30 |
mm |
Pin length |
4-5 |
mm |
Weight |
~8 |
grams |
Mounting Hole Distance |
18 |
mm |
Pin Pitch |
2.54 |
mm |
There are different ways to use this sensor in applications. This is a common gas sensor in different domains of daily life. The basic and most common examples of its applications are given here:
Industrial flammable gas alarm
Portable gas detector
Domestic gas leakage alarm
Air quality monitor
Educational projects
Smart home devices
Robotics
Automotive
Agriculture
Healthcare
Hence, in this way, we have studied the mQ-5 natural LPG sensor in detail. We started this learning through the basic introduction of this sensor. We saw that it can detect multiple gases but it is most precise for the MQ-5 natural LPG. We studied the basic features and specifications through its datasheet and saw different graphs to understand its working. Just after that, we understood the pin configuration and working principle of this sensor. In the end, we saw the table for the physical dimension and the applications of this gas sensor. I hope I have covered all the topics but if you want to learn more, you can ask us.
Hello readers! I hope you are doing great. Today we are discussing the features and details of the MQ-4 methane gas sensor, which belongs to the popular gas sensor MQ family. We have been working on other gas sensors as well, but MQ-4 is particularly suitable for detecting the presence of methane gas. This sensor is more popular because methane gas and compressed natural gas (CNG) are widely used for cooking and other related purposes. MQ-4 methane gas sensor is an important part of the home safety system. Some other advantages of this sensor are, that it responds instantly and has a potentiometer that adds versatility to its functions.
In this article, we are going to study the MQ-4 methane sensor from scratch. We’ll go through its introduction and will study the basic components of its datasheet. We’ll see some performance graphs and study the internal structure of this sensor. After that, we’ll move towards the external circuit and its working features. In the end, there will be a study of its applications. This is going to be an easy and informative article, so let’s move on to the first point:
Methane gas is widely used everywhere, and we’ve seen multiple cases of gas leakage. Therefore, the MQ-4 methane gas sensor has a special place in different applications in almost every domain of life. The MQ-4 methane gas sensor is a metal oxide semiconductor (MOS) that detects the presence of methane gases and then provides the result in the form of analog values. In this way, it provides information about the gas concentration, and its range is 300 ppm–10,000 ppm which is enough to detect leakage.
The basic structure of this gas sensor includes the following:
The sensitivity of this detector for different gases may vary but overall, it is a good choice for detecting any gas leakage. This sensor can detect gases like:
The ignition of these gases is extremely exothermal, so these produce a large amount of what. Therefore, the MQ-4 methane sensor is a life-saving element.
Till now, we have seen the basic features of this sensor but now, we are going to discuss the details of its functions. Here are some important points that will highlight the importance of this sensor:
There are multiple types of specifications, and I’ve divided them into different groups for clarification. Here is the table that shows the standard work condition parameters and their details:
Parameter |
Technical condition |
Circuit voltage (Vc) |
5V ± 0.1 |
Heating voltage (VH) |
5V ± 0.1 |
Load resistance (PL) |
20 kΩ |
Heater resistance (RH) |
33 Ω ± 5% |
Heating consumption (PH) |
Less than 750 mW |
Now, here are some important environmental parameters for the MQ-4 methane sensor:
Parameter |
Symbol |
Value |
Using Temperature |
Tao |
-10℃ - 50℃ |
Storage Temperature |
Tas |
-20℃ - 70℃ |
Related Humidity |
RH |
Less than 95%Rh |
Oxygen Concentration |
O2 |
21% (standard condition) |
The sensitivity characteristics of this sensor, along with important parameters, are given below:
Parameter |
Symbol |
Value |
Sensing Resistance |
Rs |
10KΩ - 60KΩ |
Concentration Slope Rate |
α |
≤ 0.6 |
Temperature |
- |
20℃ ± 2℃ |
Circuit Voltage |
Vc |
5V ± 0.1 |
Humidity |
- |
65% ± 5% |
Heating Voltage |
Vh |
5V ± 0.1 |
Preheat Time |
- |
Over 24 hours |
The internal structure of the MQ-4 methane sensor is similar to that of its other daily members. Here is the detailed internal structure diagram that will help you understand the information we’ll discuss in the next section:
As discussed before, the MQ-4 methane sensor has different sensitivity levels for different gases. Based on multiple experiments, here is the graph that describes the sensitivity results:
The temperature and humidity around the MQ-4 methane sensor play a crucial role in the performance scale. Here is the graph that shows the change in the sensor’s behavior with varying temperatures and humidity:
Here,
Rs = The sensing resistance that depends on the concentration of the target gas. In the case of MQ-4, the target gas is methane.
R0 = The resistance of the sensor in clean air. It is the baseline resistance of the sensor when there is no methane present in the air.
Rs/R0 = It is the ratio of sensing resistance to the resistance in clean air. It is calculated to understand the relative change in the resistance of the sensor, and it depends on the target gas concentration.
If you want to see the detailed datasheet of the MQ-4 methane gas sensor, then you can visit the link MQ-4 Methane Gas Sensor.
Now, it is time to discuss the external structure of this sensor. Just like most of the members of the MQ sensors, this sensor has four pins. The name of each pin and its function are given in the table below:
Pin Name |
Description |
VCC |
This pin powers the module and typically has an operating voltage of +5 volts. |
GND |
This pin is used to connect the module to the system's ground terminal |
Digital Out (DO) |
This pin is used to get digital output from the sensor. It is done by setting a threshold value using the potentiometer of the sensor. |
Analog Out (AO) |
This pin outputs 0-5V analog voltage, which is based on the intensity of the gas |
For the convenience of the user, the MQ-4 methane sensor comes in different packages. Here is the table that will show a brief introduction to the available packages:
Feature |
DIP |
SMD |
TO-220 |
Custom Module |
Package type |
Through-hole |
Surface mount |
Through-hole |
Encapsulated module |
Size |
Large |
Small |
Large |
Varies by module |
Ease of use |
Easy (breadboard compatible) |
Requires soldering & reflow oven |
Moderate (soldering) |
Easy (plug-and-play) |
Power requirements |
Low |
Lower than TO-220 |
Highest |
Varies by module |
Additional circuitry |
Requires external circuit |
Integrated circuit |
Integrated circuit |
Varies by module (may include voltage regulation, communication) |
Applications |
Hobby projects, prototyping |
Commercial electronics, space-constrained designs |
Industrial gas detection |
Beginner projects, quick integration |
Considerations |
Limited space for additional components |
Requires soldering expertise |
Larger size, higher power draw |
May lack specific features |
Here is a list of some other alternatives that are used in place of the MQ-4 methane gas sensor, along with the types of gases these can sense:
The MQ-4 methane gas sensor is a common instrument available on multiple platforms, but one must always choose reliable sources. These sensors are proven to be life saviors, so I would suggest you buy them from the options given below:
eBay
AliExpress
Amazon
The working principle of the MQ-4 methane gas sensor is similar to that of the other MQ sensors. Let's discuss each component of this sensor and its role in the final result:
The basic workings of the MQ-4 methane gas sensor depend on the electrical conductivity of the metal oxide semiconductor (MOS) material used in the structure of this sensor.
The MOS is also known as the chemiresistors, which means the electrical conductivity changes when these come into contact with the gas vapors.
The sensor has a heating element at its core, the duty of which is to maintain a constant heating temperature of around 300°C. This is a crucial process for the right response of the sensor.
As soon as the methane gas comes into contact with the metal oxide semiconductor (MOS), it is absorbed onto its surface. The surface already has oxygen ions, and when these ions contact the vapors, they start reacting with them.
The reaction between the oxygen ions and methane results in a decrease in the conductivity of the MOS layer. This change is directly proportional to the amount of methane present in the surrounding air of the MQ-4 methane gas sensor.
The change in conductivity resulting from the previous step is measured as the change in voltage across the sensor electrodes. The greater the resistivity change, the greater the voltage change across the electrodes.
Here is the table that shows the physical dimensions, their values, and additional notes of these parameters:
Dimension |
Value |
Units |
Notes |
Diameter |
20 |
mm |
N/A |
Height |
30 |
mm |
N/A |
Pin length |
4-5 |
mm |
Can vary slightly depending on manufacturer |
Weight |
~8 |
grams |
N/A |
Mounting Hole Distance |
18 |
mm |
Center-to-center distance between holes |
Pin Pitch |
2.54 |
mm |
Distance between pin centers |
Till now, we have been discussing the basic output of the MQ-4 methane gas sensor but now, we’ll understand how this small instrument can be used in different ways to get the required output. Here are some important examples of applications where an MQ-4 methane gas sensor is used as the heart of the circuit:
So, today we have seen the details of the MQ-4 methane gas sensor. We started with the basic introduction of this sensor and then saw the basic points of its datasheet. After that, we’ve seen the pin configuration and workings of this sensor. We understood every step of its operation and saw the physical dimensions of this methane gas sensor. In the end, we give some important examples where the MQ-4 methane gas sensor is used as the base. I hope you have understood each point, but if something is confusing, you can ask questions in the comment section.