falohun-2016-ijca-908473.pdf — page 1

International Journal of Computer Applications (0975 – 8887) 
Volume 135 – No.7, February 2016 
30 
Dangerous Gas Detection using an Integrated Circuit 
and MQ-9 
Falohun A.S. 
Dept. of Computer Sc. & Eng. 
Ladoke Akintola Univ. of Tech. 
 
Oke A.O. 
Dept. of Computer Sc. & Eng. 
Ladoke Akintola Univ.of Tech. 
Abolaji B.M., Oladejo 
O.E. 
Dept. of Computer Sc. & Eng. 
Ladoke Akintola Univ.of Tech.     
 
ABSTRACT 
Natural gas is an odourless one which consists of compounds 
made of two elements: carbon and hydrogen called 
hydrocarbons. Sometimes, due to an accident or if the valve is 
not properly closed, the gas leaks. This system is aimed at 
detecting the leakage and sounding an alert so that occupants 
in the building can maintain optimal ventilation and turn off 
all electrical appliances or evacuate the vicinity until a redress 
is made. 
An MQ-9 chemical sensor coupled with an Integrated Circuit 
was used to build the system and on testing, the system gave 
adequate visual information, audible and timely alert on 
detecting a gas leakage. 
General Terms 
Security, Safety, Signal, Gas, Casing. 
Keywords 
Sensor, Buzzer, Embedded, Soldering, Alarm. 
1.  INTRODUCTION 
In this fast developing society, electronics has come to stay as 
the most important branch of Engineering. Electronic devices 
are being used in almost all industries for quality control and 
automation and they are fast replacing the present vast army 
of workers engaged in processing and assembling in the 
factories. These devices supplement the human ability to 
sense, monitor, calculate, observe, and control. [8]  
An uncontrolled combination of fuel with oxygen releases 
heat and any unintended contact with a spark can cause 
burning. Automatic gas detecting systems are intended to 
notify the building occupants to evacuate in the event of the 
gas leakage or other emergency, report the event to an off-
premises location in order to summon emergency services, 
and to prepare the structure and associated systems to control 
the spread of gas and fire. [3]  
This work is about the design and construction of a gas 
detector with audible alarm. This gas detector with audible 
alarm is designed with the intention to ensure that the event of 
gas 
is 
intelligently 
detected, 
promptly 
notified 
and 
interactively managed than what is obtainable with 
conventional ``ring-ring´´ fire alarm systems. 
„Jet Age‟ is what the age is called as the growing desire of 
human, is that things are done in the twinkle of an eye (i.e. 
food get cooked in a minute, uninterrupted power supply, fast 
transportation of people and loads, fast access to knowledge 
base 
(Internet), 
Internet 
banking, 
social 
media 
communication, online classes). And these have led to breath-
taking inventions to cater for these desires. One of such is the 
gas-cooker, whose work is of great benefit. It is observed that 
the destruction caused by fire due to gas leakage is quite 
alarming and building occupants are slow in responding to 
alarm systems. Dr. Guylène Proulx in [6] discussed three 
reasons why occupants may ignore the alarm signal as: 
 
Failure to recognize the signal as a fire alarm. 
 
Loss of confidence in the system because of 
nuisance alarms, or, 
 
Failure to hear the signal if there is other source of 
sound apart from the alarm system or the resident is 
partly with deafness disability. 
Therefore, a gas detector with audible/visual alarm presented 
herein tends to solve these identified problems through the 
design and construction of a low-cost, easy to construct gas 
detection system via gas sensor. Figure 1 gave a hint on the 
alarm system built around a Timer which is easy to work with, 
affordable and easy to design and construct, instead of a 
Microcontroller. 
 
 
 
 
Figure 1: Block diagram of the user-interactive fire alarm 
system. 
2. LITERATURE REVIEW 
2.1 Gas Alarm Systems 
An automatic gas alarm system is designed to detect the 
unwanted presence of fire by monitoring environmental 
changes associated with combustion. [2] 
In general, a fire alarm system is classified as either 
automatically actuated, manually actuated, or both. [5]. 
Automatic fire alarm systems are intended to notify the 
building occupants to evacuate in the event of a fire or other 
emergency, report the event to an off-premises location in 
order to summon emergency services, and to prepare the 
structure and associated systems to control the spread of fire. 
2.2 Parts of a Fire Alarm System 
Primary Power supply: Commonly the non-switched 120 or 
240 Volt Alternating Current source supplied from a 
commercial power utility. In non-residential applications, a 
branch circuit is dedicated to the fire alarm system and its 
constituents. "Dedicated branch circuits" should not be 
confused with "Individual branch circuits" which supply 
energy to a single appliance. 
Secondary (backup) Power supplies: This component, 
commonly consisting of sealed lead-acid storage batteries or 
other emergency sources including generators, is used to 
supply energy in the event of a primary power failure. 
GAS 
SENSOR 
TIMER 
AUDIO ALERT 
UNIT 
VISUAL ALERT 
UNIT