1.      Introduction

The rapid growth of industrialization and urbanization has resulted in a significant increase in the use of combustible and toxic gases such as LPG, CNG, methane, propane, hydrogen, and alcohol vapours across domestic, commercial, and industrial sectors. Although these gases are essential for energy and production processes, their leakage poses severe safety risks, including fire outbreaks, explosions, suffocation, and long-term health complications. According to global fire and safety statistics, a substantial number of industrial and household accidents occur due to undetected gas leakage [3], [4], [6],[7].

A major challenge in gas leakage prevention is that many hazardous gases are invisible and odourless, making human sensory detection ineffective. Manual inspection methods and conventional safety practices suffer from delayed response, human error, and lack of continuous monitoring. In confined or poorly ventilated spaces, leaked gas can accumulate rapidly and reach explosive concentration limits within a short duration, increasing the probability of catastrophic incidents [4], [7].

To overcome these limitations, automated gas detection systems based on electronic sensors and embedded controllers have become increasingly important. Semiconductor gas sensors such as the MQ series offer high sensitivity, fast response, and compatibility with microcontroller-based platforms [1], [8]. Embedded systems enable real-time data acquisition, processing, and decision-making, allowing immediate alert generation during hazardous conditions [5], [9],[10]..

In this context, the proposed Smart Nose for Hazardous Zone system is designed as a compact, portable, and low-cost safety solution that continuously monitors gas concentration using an MQ-2 sensor and activates an audible alarm through a buzzer when unsafe levels are detected. The Arduino Uno microcontroller serves as the processing unit, ensuring reliable operation, easy programmability, and scalability. The battery-powered architecture makes the system suitable for installation in remote and power-restricted environments such as fuel storage units, industrial plants, laboratories, vehicle garages, and household kitchens.

2.       Architecture

The Smart Nose for Hazardous Zone system follows a simple yet effective embedded hardware architecture comprising four major functional blocks: sensing unit, processing unit, power management unit, and alert unit. The MQ-2 gas sensor acts as the sensing module, continuously monitoring the surrounding environment for the presence of flammable and toxic gases. The analog output signal generated by the sensor varies with gas concentration and is supplied to the Arduino Uno microcontroller for processing.

The Arduino Uno functions as the central processing unit of the system. It continuously reads sensor data through its analog input pins, compares the measured value with a predefined safety threshold, and determines whether the detected gas concentration exceeds permissible limits. When hazardous conditions are identified, the microcontroller activates the buzzer alarm to warn nearby individuals.

The system is powered using a 9V battery connected through a manual switch, enabling standalone and portable operation without dependency on external power sources. This design ensures uninterrupted monitoring in hazardous zones, even during power outages. The overall architecture enables fast response, real-time detection, and effective alert generation, thereby reducing the risk of gas-related accidents [2], [3].

Fig. 1: Architecture of Smart Nose for Hazardous Zone

The Smart Nose for Hazardous Zone system follows a simple yet effective embedded hardware architecture comprising four major functional blocks: sensing unit, processing unit, power management unit, and alert unit. The MQ-2 gas sensor acts as the sensing module, continuously monitoring the surrounding environment for the presence of flammable and toxic gases. The analog output signal generated by the sensor varies with gas concentration and is supplied to the Arduino Uno microcontroller for processing.

The Arduino Uno functions as the central processing unit of the system. It continuously reads sensor data through its analog input pins, compares the measured value with a predefined safety threshold, and determines whether the detected gas concentration exceeds permissible limits. When hazardous conditions are identified, the microcontroller activates the buzzer alarm to warn nearby individuals.

The system is powered using a 9V battery connected through a manual switch, enabling standalone and portable operation without dependency on external power sources. This design ensures uninterrupted monitoring in hazardous zones, even during power outages. The overall architecture enables fast response, real-time detection, and effective alert generation, thereby reducing the risk of gas-related accidents [2], [3].

I.     HARDWARE COMPONENTS

A.    Arduino Uno

The Arduino Uno is an open-source microcontroller board based on the ATmega328P and is widely used in embedded and automation applications due to its simplicity, reliability, and cost effectiveness [2], [5]. It provides multiple digital and analog I/O pins, enabling easy interfacing with sensors and actuators. In this project, the Arduino Uno processes the analog signal from the MQ-2 gas sensor and controls the buzzer alarm during hazardous conditions.

Fig.2: Arduino PINOUT

B.    Power Supply (9V Battery)

A 9V battery is used as the primary power source to ensure portability and independent operation. Battery-based power supply allows deployment in locations where continuous electrical power is unavailable, such as storage rooms, gas cylinders areas, and remote industrial environments.

C.    MQ-2 Gas Sensor

The MQ-2 is a semiconductor-type gas sensor capable of detecting LPG, methane, propane, butane, hydrogen, alcohol vapours, and smoke. It operates based on resistance variation of tin dioxide (SnO₂) when exposed to combustible gases [1], [7], [8]. The sensor offers high sensitivity, fast response time, and wide detection range (300–10,000 ppm), making it suitable for real-time safety applications.

D.   Switch

A manual ON/OFF switch is incorporated to control the power supply to the system. This helps conserve battery life and ensures safe handling during installation and maintenance [4], [5].

E.     Buzzer Alarm

The buzzer serves as the alert unit of the system. When the gas concentration exceeds the predefined threshold, the Arduino activates the buzzer to produce an audible warning, ensuring immediate awareness of hazardous conditions.

II.             PROTOTYPE IMPLEMENTATION

Figure 3 illustrates the Circuit design model of Smart nose for hazardous zone. The components are assembled on a breadboard and interconnected using jumper wires. The prototype validates the practical feasibility of the proposed architecture and demonstrates successful integration of sensing, processing, and alert modules [6].

Fig.3: Circuit design model of Smart nose for hazardous zone

The Smart Nose for Hazardous Zone system is based on an embedded hardware architecture that integrates sensing, processing, power management, and alarm indication modules. The architecture is designed to continuously monitor the surrounding environment for the presence of hazardous gases and respond automatically when danger is detected. At the core of the system lies the Arduino Uno microcontroller, which acts as the central processing unit responsible for receiving sensor data, executing programmed decisions, and controlling output responses. The system is powered using a 9V battery connected through a switch, enabling portable and uninterrupted operation even in remote hazardous locations where external power sources are unavailable

  This architecture ensures fast detection, real-time response, and effective warning to minimize the risk of gas related accidents

3. Results and Discussion

The Smart Nose for Hazardous Zone system was successfully designed, implemented, and experimentally evaluated to verify its performance in detecting hazardous gas leakage and generating timely alert signals. The hardware prototype, consisting of the Arduino Uno, MQ-2 gas sensor, buzzer, battery, and switch, operated reliably under different test conditions.

Fig. 4: Hardware model

Figure 4 illustrate the complete hardware model of the proposed system. During experimentation, the MQ-2 gas sensor demonstrated high sensitivity to combustible gases such as LPG, methane, and butane. When exposed to clean air, the sensor output remained stable below the predefined threshold level. Upon the introduction of gas near the sensing module, a rapid change in sensor resistance was observed, resulting in an increased analog output signal. This variation was accurately detected by the Arduino Uno through its analog input pin, confirming effective sensor–microcontroller interfacing [1], [2].

Once the detected gas concentration exceeded the programmed safety threshold, the Arduino Uno immediately triggered the buzzer alarm. The response time of the system was found to be minimal, ensuring prompt warning to nearby individuals. This fast reaction is critical in preventing gas accumulation and potential ignition in confined or high-risk environments. Similar response behavior has been reported in earlier embedded gas leakage detection systems, validating the reliability of the proposed design [3], [4].

The system maintained stable operation during continuous monitoring, with no false triggering observed under normal atmospheric conditions. Battery-powered operation allowed uninterrupted functioning without dependency on external power sources, making the device suitable for portable and remote hazardous locations. The low power consumption of the Arduino Uno and MQ-2 sensor further supports long-duration deployment in real-world safety applications [2], [5].

Compared to conventional manual gas inspection methods, the proposed system provides continuous real-time monitoring and immediate alert generation, significantly reducing the risk of delayed detection. The compact design, low component cost, and ease of installation make the system economically viable for large-scale deployment in households, laboratories, fuel stations, and industrial facilities. The obtained results align with existing studies emphasizing the effectiveness of embedded and sensor-based gas safety systems in reducing fire hazards and improving workplace safety [6], [7], [8].

The experimental results confirm that the Smart Nose for Hazardous Zone system delivers accurate gas detection, rapid alarm response, and reliable performance, fulfilling the intended safety objectives of the project.

4.       Conclusion

This research paper has presented the design and development of the Smart Nose for Hazardous Zone system, an embedded safety device intended for reliable detection of flammable and toxic gas leakage. The project demonstrates the effective integration of the Arduino Uno microcontroller, MQ-2 gas sensor, buzzer, and portable power supply to provide real-time monitoring and immediate alert response during hazardous conditions. The experimental implementation proves that the system can accurately sense abnormal gas concentrations and trigger an alarm at the correct threshold, thereby offering a practical and low-cost solution for preventing fire accidents, explosions, and health risks

                                ACKNOWLEDGMENT

I would like to thank our Head of the department Prof. (Dr.)   Pankaj Jha for his continuous guidance, valuable suggestions, and constant encouragement throughout the completion of this project. His expertise, support, and insightful feedback played a significant role in shaping the development of this work and enhancing my understanding of embedded system applications.