The MQ5 Gas Sensor is a versatile and highly sensitive device that enables easy detection of gas leaks in both residential and industrial settings. It offers the capability to identify various substances such as alcohol, H2, LPG, CH4, and more. With its exceptional sensitivity and rapid response time, this sensor allows for quick and practical gas measurements. Operating on the principle of a Metal Oxide Semiconductor (MOS) type Gas Sensor, commonly referred to as Chemiresistors, it detects gases by monitoring changes in the resistance of its sensing material upon exposure to the gas. The MQ5 Sensor is a reliable tool for enhancing safety and facilitating efficient gas detection applications.

 

Package Includes:

• 1x MQ5 LPG Sensor

 

Features:

• Analog Output Voltage: It provides a 0 ~ 5V analog output voltage, where the voltage increases as the gas concentration rises. This feature allows for easy interpretation and integration with other systems.
• Enhanced Sensitivity: The module exhibits better sensitivity towards gases such as liquefied petroleum gas (LPG), natural gas, and city gas. This sensitivity enables accurate detection and monitoring of these gases.
• Long-Life and Reliable Stability: With its robust design and high-quality components, the MQ-5 Sensor module offers long-term durability and reliable stability. It can withstand continuous operation and provides consistent performance over time.
• Fast Response and Recovery: The module demonstrates rapid response and recovery characteristics, ensuring quick detection and timely alerts in case of gas leaks or changes in gas concentration.
• Operating Voltage: The module operates at a DC 5V voltage, making it compatible with common power sources and microcontroller systems.
• Detection Range: The MQ-5 Sensor module is specifically designed to detect LPG and CH4 gases within a concentration range of 300 to approximately 10,000ppm. Additionally, it can also detect H2, CO, and alcohol, expanding its versatility for various gas detection applications.

 

Description:

The MQ-5 Gas Sensor is an advanced and highly versatile device designed to detect a wide range of gases with precision and reliability. It is commonly used in industries and residential applications to identify gas leaks promptly, ensuring the safety of individuals and the environment. This sensor module features a 0 ~ 5V analog output voltage, where the voltage level corresponds to the detected gas concentration. Higher gas concentrations result in higher output voltages, allowing for easy interpretation and integration with other monitoring systems. The MQ-5 Sensor exhibits exceptional sensitivity towards gases such as liquefied petroleum gas (LPG), natural gas, and city gas. It is specifically optimized to detect these gases effectively, providing accurate readings even at low concentrations. This sensitivity is crucial for the early detection and prevention of gas-related hazards. With a long lifespan and reliable stability, the MQ-5 Sensor ensures consistent and dependable performance over an extended period. It's high-quality components and robust construction contribute to its durability, making it suitable for continuous operation in demanding environments.

With its impressive response and recovery characteristics, the MQ-5 Gas Sensor swiftly detects and measures gas concentrations, ensuring prompt identification of potential hazards. This exceptional speed is especially vital in time-sensitive scenarios, enabling immediate actions to mitigate risks effectively. Operating at a convenient DC 5V voltage, the MQ-5 Sensor seamlessly integrates into a wide range of electronic systems, leveraging its compatibility for enhanced versatility in various projects and applications. The MQ-5 Sensor is meticulously calibrated to detect LPG and CH4 gases across a concentration range spanning from 300 to approximately 10,000ppm. Moreover, its capabilities extend beyond these gases, encompassing the detection of hydrogen (H2), carbon monoxide (CO), and alcohol. This expanded gas detection capacity broadens the sensor's utility, making it an invaluable asset for diverse gas detection needs across multiple industries and domains.

 

Principle of Work:

The MQ5 Gas Sensor operates on the principle of detecting the presence and concentration of LPG (liquefied petroleum gas) in the surrounding environment. It accomplishes this by measuring the analog signal generated by the sensor in response to the detected gas. The sensor's analog output is directly proportional to the concentration of LPG present in the air, The MQ5 Gas Sensor utilizes a Metal Oxide Semiconductor (MOS) technology to detect the presence and concentration of gases, particularly LPG (liquefied petroleum gas). The sensor consists of a sensing element coated with a metal oxide film that undergoes changes in its electrical conductivity when exposed to specific gases. When the MQ5 sensor is powered, it heats up the sensing element using an integrated heating element. This heating process is essential for the sensor's operation as it enables the interaction between the gas molecules and the metal oxide surface. As the gas molecules come into contact with the heated surface, a chemical reaction occurs, causing the conductivity of the metal oxide film to change. The sensing element's electrical conductivity varies depending on the concentration of LPG gas in the environment. Higher LPG concentrations lead to an increase in the conductivity of the metal oxide film, while lower concentrations result in decreased conductivity. This change in conductivity is primarily due to the absorption and desorption of gas molecules on the surface of the sensing element. It is important to note that the MQ5 Gas Sensor is specifically calibrated to detect LPG gas, but it can also exhibit some sensitivity to other gases such as methane (CH4), hydrogen (H2), carbon monoxide (CO), and alcohol. However, for accurate and reliable measurements, it is recommended to use the sensor within its designed range and specifically for LPG detection. To utilize the sensor effectively, most microcontrollers (MCUs) are equipped with an integrated Analog-to-Digital Converter (ADC). This ADC can be employed to read the analog output signal from the MQ5 Gas Sensor. By leveraging the MCU's signal processing capabilities, the observed analog voltage can be transformed into a quantifiable measurement of the LPG concentration in the air. With this measurement at hand, appropriate actions can be taken based on predetermined thresholds. For instance, if the LPG concentration exceeds a certain level, an alarm can be triggered to alert individuals to the potential gas leak or hazard. This allows for timely responses and interventions to ensure safety and mitigate any risks associated with LPG gas presence.

 

Pinout of the Sensor:

The MQ5 Gas Sensor has six pins, which are categorized into three types: A pins, B pins, and H pins (Heater pins). Here is a clear pinout of the sensor:

1. A Pins: The sensor has two A pins, one on the upside and one on the downside. These pins can be connected together and connected to the +5V DC supply. By applying the positive voltage to the A pins, the sensor is powered.
2. B Pins: Similar to the A pins, there are two B pins, one on the upside and one on the downside. These pins can be connected together and linked to the output terminal. Connecting the B pins together allows the analog output signal to be obtained from the sensor.
3. H Pins (Heater pins): The center two pins are referred to as H pins or Heater pins. Each H pin is connected to an independent electrochemical sensor within the sensor module. These pins should not be connected directly to an Arduino or microcontroller due to their high current consumption. Instead, they need to be connected individually to the +5V power supply and GND.

To adjust the sensitivity of the sensor, a resistor labeled Rl can be added to the circuit. The value of the Rl resistor can be chosen between 2K to 47K ohms. Using a lower-value resistor reduces the sensitivity of the sensor while using a higher-value resistor increases the sensitivity. It's important to note that higher sensitivity may result in less accuracy in detecting higher gas concentrations.

 

Applications:

1. Gas Leakage Detection: The sensor is widely used for detecting and monitoring gas leaks, particularly LPG (liquefied petroleum gas) and CH4 (methane). It provides an early warning system to prevent potential accidents and hazards in homes, commercial buildings, and industrial settings.
2. Industrial Safety: The MQ5 Gas Sensor is employed in industrial environments to ensure worker safety. It can detect the presence of hazardous gases and trigger alarms or shutdown systems to prevent any potential risks or accidents.
3. Gas Detection in Appliances: The sensor is used in gas-powered appliances such as stoves, ovens, and water heaters to monitor gas levels and ensure safe operation. It provides an additional layer of protection by alerting users to gas leaks and preventing potential fire or explosion hazards.
4. Environmental Monitoring: The MQ5 Gas Sensor is utilized in environmental monitoring systems to measure and track gas emissions. It helps in assessing air quality, detecting pollution sources, and implementing appropriate measures for pollution control.
5. Gas Detection in Laboratories: The sensor is employed in laboratory settings to detect and monitor the presence of gases during experiments or in chemical storage areas. It ensures the safety of lab personnel by alerting them to any potential gas leaks or hazardous conditions.
6. Gas Detection in Vehicles: The MQ5 Gas Sensor can be integrated into automotive systems to monitor the presence of gases, such as LPG or methane, in vehicles. It helps ensure the safety of passengers and prevents gas-related incidents.
7. Fire Detection: The sensor can be used as a component in fire detection systems to detect the presence of flammable gases, triggering alarms and initiating fire suppression mechanisms.
8. Gas Monitoring in Agriculture: The MQ5 Gas Sensor is employed in agricultural settings to monitor gas emissions from livestock waste or storage facilities. It aids in maintaining a healthy environment for animals and preventing the buildup of harmful gases.

 

Circuit:

1. Replace the 10K resistor connected to the B pin with a variable resistor if you need adjustable sensitivity. This allows you to fine-tune the sensitivity level of the gas sensor according to your requirements.
2. Connect the A and H pins of the MQ-5 sensor to the +5V power source pin of the Arduino board. The separate H pin should be connected to the GND (ground) pin of the Arduino board.
3. Both B pins of the sensor should be connected to the Analog pin A0 of the Arduino board. This allows you to read the sensor's analog output.
4. Test the sensor's response by exposing it to LPG gas from an oven or a lighter. Observe the readings on the Serial Monitor to see how they change abruptly when the gas is detected. This helps you validate the sensor's functionality and sensitivity adjustments.

 

Library:

This Module doesn't need any Library to function.

 

Code:

This example code reads the analog input from an MQ5 gas sensor connected to the Arduino's analog pin A0. It initializes the serial communication, waits for the MQ5 sensor to warm up for 20 seconds, and then enters the main loop. Inside the loop, it reads the sensor value and prints it to the serial monitor. If the sensor value exceeds 400, it turns on an LED connected to pin 13. Otherwise, it turns off the LED. There is a delay of 2 seconds before the next sensor reading is taken.

#define MQ5pin A0 // Define the analog input pin for MQ5 sensor
int ledPin = 13; // Define the pin for the LED

void setup() {
pinMode(ledPin, OUTPUT); // Set the LED pin as an output
Serial.begin(9600); // Initialize the serial communication
Serial.println("MQ5 warming up!");
delay(20000); // Allow the MQ5 to warm up
}

void loop() {
int sensorValue = analogRead(MQ5pin); // Read the analog input from MQ5 sensor
Serial.print("Sensor Value: ");
Serial.println(sensorValue);

if (sensorValue > 400) {
digitalWrite(ledPin, HIGH); // Turn on the LED if sensor value exceeds 400
} else {
digitalWrite(ledPin, LOW); // Turn off the LED otherwise
}

delay(2000); // Delay for 2 seconds before next reading
}

 

• The MQ5pin is defined as A0, which corresponds to analog input pin 0 on the Arduino board.
• The variable sensorValue is declared and initialized within the loop function to improve code readability and maintainability.
• The ledPin is defined as an integer to clearly indicate its purpose and make it easier to modify if needed.
• The pinMode for the LED pin is set explicitly as OUTPUT for better clarity.
• The comments are revised to be more concise and provide clearer explanations.
• The digitalWrite function is used with HIGH and LOW constants to explicitly indicate turning the LED on or off.
• The delay period is maintained as 2 seconds for consistency with the original code.

 

Technical Details:

• Heater Voltage: 5.0V
• Power Supply: 5 Volts
• Working Current: 150mA
• Preheat time: Over 20s
• Heater Resistance: 31±10%
• Sensing Resistance Range: 10 – 60K
• Sensor Heat Consumption: 0.5-800mW
• Detecting Concentration: 200-10000ppm

 

Resources:

MQ-5.pdf 

 

Comparisons:

When comparing the use of the MQ5 sensor with the use of the MQ5 sensor module, there are a few key differences to consider:

1. Ease of Use: The MQ5 sensor module typically comes with additional components and circuitry integrated into a single module, making it easier to connect and use compared to using the standalone MQ5 sensor. The module may have built-in voltage regulation, signal conditioning, and output interfaces, simplifying the setup process.
2. Convenience: With the MQ5 sensor module, you don't need to worry about wiring individual components and ensuring proper connections. The module provides standardized pins or connectors that can be easily plugged into the Arduino or other microcontroller boards, saving time and effort.
3. Flexibility: Using the standalone MQ5 sensor allows for greater flexibility in terms of customization and integration into specific projects. You have more control over the design and can incorporate the sensor into a custom circuit or system according to your specific requirements.
4. Expandability: While the MQ5 sensor module provides convenience, it may have limited expandability options. On the other hand, using the standalone MQ5 sensor gives you the flexibility to add additional components or sensors to the circuit as needed, allowing for more complex and customized setups.
5. Cost: The standalone MQ5 sensor is generally more cost-effective compared to the MQ5 sensor module. If you already have the necessary components and prefer a DIY approach, using the standalone sensor may be a more economical choice.

The choice between using the MQ5 sensor or the MQ5 sensor module depends on the specific project requirements, level of expertise, and the balance between convenience and customization.