See discussions, stats, and author profiles for this publication at: https://www.researchgate.
net/publication/348606912
Design and Construction of Cooking Gas (LPG) Leakage Detector
Conference Paper · January 2021
CITATIONS READS
0 712
3 authors:
Peter ANADEBE Okonkwo Amarachukwu Obi
University of Nigeria University of Nigeria
2 PUBLICATIONS 1 CITATION 9 PUBLICATIONS 6 CITATIONS
SEE PROFILE SEE PROFILE
Idoko Solomon
University of Nigeria
1 PUBLICATION 0 CITATIONS
SEE PROFILE
Some of the authors of this publication are also working on these related projects:
Circuit Breakers and Feeders in Nigeria View project
Design Construction and Testing of Hybrid Photovoltaic/Thermal (PV/T) Thermosiphon Flat Plate Solar Water Heater View project
All content following this page was uploaded by Amarachukwu Obi on 06 February 2021.
The user has requested enhancement of the downloaded file.
Design and Construction of Cooking Gas
(LPG) Leakage Detector
Okonkwo P. A., Obi A. I.a , Idoko S. O.
Department of Mechanical Engineering, University of Nigeria, Nsukka
a Corresponding Author. Email: amarachukwu.obi@unn.edu.ng
Abstract
The growing incidence of domestic and industrial fire accidents as a result of leakage of cooking gas also known as Liquefied
Petroleum Gases (LPG), has generated a lot of concerns in the society. This has propelled inquisitions by researchers targeted
at discovering how to prevent and control the menace of domestic and industrial fire accidents, arising from the leakage of
LPGs from cylinders and other containers of the gas. LPG has the characteristic of being highly inflammable. And the risk
of spark ignition of the gas, if present in high concentrations in an environment, leading to fire explosion is compounded by
its characteristic odourless nature. This makes it difficult for human beings to detect the presence of LPG at certain levels
of concentration in an environment. Although, nowadays, attempts have been made to odourize LPG, to enable human
perception in an environment if leakage occurs from the storage cylinder; this has not been very effective in preventing
incidences of domestic cooking gas fire accidents. In this work, effort has been made to design and fabricate a cooking gas
(LPG) leakage detector by incorporating an MQ6 sensor, with a beeping buzzer, LED light, LCD display unit together
with an arduino controlled SIM800L Module for SMS alert. This device is capable of detecting the concentration level of
LPG in parts per million (ppm), in an environment. When in operation, once the calibrated MQ6 sensor detects the preset
concentration level of LPG in any environment, the user is alerted by the beeping of the buzzer, light from an LED, a display
of the gas concentration level on an LCD generator as well as an SMS alert from an arduino controlled SIM800L Module.
Keywords: leakage; LPG; MQ6; Arduino; LED light; SIM800L
1. Introduction ing combustible gases. The concerns for deforestation,
inadequate and often erratic power supply from the na-
In the olden days, men worked in harmful environ- tional grid, and the rising cost of kerosene coupled with
ments knowing and unknowingly. Even when the en- issues of kerosene adulteration have pushed up the de-
vironment was known to be harmful, risky, danger- mand for consumption of LPG for both domestic, in-
ous and causing injuries and fatalities, people felt that dustrial heating and heat generation purposes.
risk was part of the job. The first working environ- Global Economy.com reports that the average daily
ment which raised human concerns as a result of the consumption of LPG has risen to about a thousand
many fatalities recorded in it, was the coalmine. The barrels per day. This increase in LPG consumption
coalmine was identified as an area housing many com- has brought on with it increased rate of accidents of-
bustible and toxic gases which caused dangerous explo- ten leading to death due to gas leakage and often ex-
sions, fire and even death in the mines. This then cre- plosion of gas cylinders. Investigations have shown the
ated the need for developing how to detect the harm- major causes of these accidents to include: faulty cylin-
ful atmosphere that was responsible for the explosion ders, faulty valves, worn out regulators, illegal or over
and fire in the coal mines, and hence, the advent of filling of gas cylinders and lack of technical know-how
gas detectors. The application of intelligent systems in on the part of the users of gas cylinders. This therefore
gas detection is expanding in both domestic and indus- presents the need for a device that can detect LPG, if
trial spheres of human endeavors. Over the years, a lot present up to a certain level of concentrations in parts
of investigations have taken place in the gas detection per million in any environment. The objective of this
field, and these have led to many innovations and ex- work is to design and construct a device for detecting
panded the scope of gas detection applications. Ever the leakage of cooking gas (LPG).
since the discovery of LPG by Dr. Watter in 1910,
these have had a significant progression by scientists 2. Review of Literature
and researchers alike attempting to proffer solutions to
the problem of dangerous gas detection with a view to Some works have been done in gas detection and
curbing the incidents of gas explosion and fire. A major some others worked on sensors that detect gas. These
breakthrough was recorded in 1925 by Dr. Jiro Tsuji, works include the classification of gas detection tech-
with his development of light wave interference. In nologies which involve electrochemical method as a re-
1929, Dr. Oliver Johnson developed a platinum cata- sult of diffusion of gases through the porous membrane
lyst in a wheatstone bridge electronic circuit for detect- to the electrode where oxidation and reduction occurs
ISBN 0000-0000 © Faculty of Engineering, UNN, 2020.
C7-2 P. A. Okonkwo et al.
and the amount of current produced is directly propor- to 13 from right to left. They are used as input in read-
tional to the amount of gas that is oxidized indicating ing levels of voltage or they can act as output so that
the concentration of gas. Oxygen and toxic gases can voltage can be applied to it. Pulse width modulation
be detected by electrochemical sensors but they can- (PWM) pins also on the hardware adjust the amount of
not detect organic compounds [1]. A catalyst on the voltage applied to it. The analogue pin of the arduino
active bead causes a change in electrical resistance of gives you access to the analogue to digital converter of
the bead by allowing combustible compounds to ox- the microcontroller and it allows you to take analogue
idize the electrode. Catalytic bead sensors are inex- signal and convert it to digital signal [9], [10] and [11].
pensive and compounds such as silicon, mineral acids After selecting the sensor, it is placed on the Arduino
and sulphur compounds poison the sensor [1].The cur- microcontroller board that matched to the PIN input,
rent that result when the ionization energy of the com- then it started scanning the analog signal that is con-
pound is greater than the light photon energy is pro- verted to digital. The digital PIN will only recognize
portional to the concentration of the gas [2]. Transi- 0 as low value and 5 volts as a high value [12]. In the
tion metal oxide semiconductor contains elements with Arduino Nano system, there is a calibration step of free
more than one oxidation states; for example, Fe2 O3 , air (RO AIR CLEAN FACTOR) right before the sen-
TiO2 , V2 O5 , SnO2 , ZnO etc. Non-transition type sor is read, to provide a more accurate data response
contains elements with only one oxidation state since while detecting the gas concentration [12]. Arduino
much energy is needed to form other oxidation states scans the response data from the sensor periodically in
[3]. The basic principle of operation of metal oxide real-time. The sensor uses the digital (ADC) value to
sensors are based on redox reactions between the tar- get Resistance (Rs), and can be found in equations 4
get gases and the metal surface. The first step of oper- and 5. Vc is the voltage from a microcontroller board.
ation involves reaction of oxygen with the molecules of VRL is the voltage generated from the sensor in the
the target gases leading to electrical variation of the ox- tested area. RL is the resistance value from the sensor
ide surface. The second step involves the transforming datasheet with kilo Ohm unit [12]. The digital value is
of the electrical variation to resistance variation of the the result from the analog to digital conversion (ADC).
sensor. Metal oxide semiconductor sensors are utilized In Arduino, the microcontroller has 10 bits resolution
to detect combustible gases as well as oxidizing gases from 0 to 1023 [12]. Once we calculate Rs and Ro we
[4]. The difference in wavelength energy is what is used can find the ratio and then using the graph shown in fig
in determining the concentration of the gas sample [5]. 3 we can calculate the equivalent value of PPM for that
Optical ways for gas sensing are based on the princi- particular gas.
ple of spectroscopy. They are applied in gas sensing A liquid crystal display (LCD) is a flat panel display
because of their high sensitivity, selectivity and rela- that uses the light-modulating properties of liquid crys-
tive stability. They are also affected by catalyst poison- tal. The LCD screen is more vitality effective than
ing. However, because they are very expensive, their a Cathode Ray Tube (CRT). A light-emitting diode
application in gas sensing is limited [6]. The sensitiv- (LED) is a two-lead semiconductor light source. It is a
ity of gases is measured at different level depending on P-n junction diode, which emits light when activated.
the area of application for example part per thousand When a suitable voltage is applied to the leads, elec-
(PPTH) is used for industrial estimation or detection of trons are able to recombine with electron holes within
the presence of LPG, part per million (PPM) and part the device, releasing energy in the form of photons
per billion (PPB) are used for more precise detection [13]. A buzzer is a sound signaling device which is
in the laboratories and at homes [6]. How sensitive a utilized in alarm devices, timers and different types of
gas sensor is, it is a function of several factors such as alarms [14], [15]. They might be mechanical, elec-
sensing materials, temperature and humidity of the en- tromechanical, or piezoelectric [11]. For this work, the
vironment, physical structure of the sensing layers, etc. buzzer utilized is the conservative, pin terminal type
However, when they are properly calibrated the effect of electromagnetic signal with 3100Hz full resonant
of some of these factors become insignificant especially frequency [15]. SIM800L GSM Module is a minia-
with metal oxide semiconductors sensors. Calibration ture GSM modem, which is used to send SMS (Short
of the sensor for the particular target gas and making Message Service) messages to a user when integrated
use of the variation in optimal conditions of operation with a microcontroller. At the heart of the module is
for other sensing target gases and the target gas in ques- a SIM800L GSM (Global System for Mobile Com-
tion [7]. munications) Cellular chip. The operating voltage of
the chip is from 3.4V to 4.4V, which makes it an ideal
3. Methodology choice for direct battery supply. The module needs an
The MQ6 (Message Queue 6) is a gas sensor mod- external antenna to connect to a network. The power
ule [8]. The module has four (4) pins for interfacing supply for this work is 8V Nickel Metal Hydride bat-
of which two pins are VCC and ground, one pin is tery for powering the microcontroller (Arduino Nano).
an analogue output pin for serial communication and The LPG detector is powered by two of this battery
the other is a digital which is also for serial commu- each producing 4.0V when fully charged. Also, the
nication. The sensor estimates the concentration of power supply for the SIM800L GSM Module is three
leaked gas in parts per million (PPM). Arduino nano (3) Nickel Metal Hydride battery each with a capac-
is a microcontroller which is a small, complete and ity of 1.3V when fully charged producing a total of
breadboard-friendly board based on the ATmega328 3.9V. Three batteries were chosen for powering the
(Arduino Nano 3.x) [9]. The board is programmed SIM (subscriber identity module) Module because the
using the arduino programming language. The digital logic voltage that the module can accept is 3.4V-4.4V
pins header on the arduino board is numbered from 0 which can be supplied by the batteries [16], [17]. The
Proceedings of the 2020 Sustainable Engineering & Industrial Technology Conference
Design and Construction of Cooking Gas (LPG) Leakage Detector C7-3
Figure 1: Integrated hardware design
TX Pin (transmitting pin) on the module is connected leakage is displayed on the LCD and the LED light is
to the digital pin 10 chosen pin on the microcontroller. switched on and sms message/messages are sent to the
The RX Pin cannot be connected to the Microcon- user.
troller’s digital pin as it uses 5V whereas the SIM800L From the sensitivity curve in the datasheet of MQ6
Module uses 3.3V level logic voltage as it is NOT 5V LPG [18] the sensing/protection resistor (4.7kΩ) and
tolerant. This means that the TX signal coming from the adjustable (0-50kΩ) are in serial which forms a load
the microcontroller must be stepped down to 3.3V so resistor R L (4.7-60kΩ) [20], [19]. The sensor’s resis-
as not to damage the SIM800L Module. In solving this tance Rs and R L forms a voltage divider. The output
problem, a 4.7Kilo ohms resistor is connected between voltage on the signal pin could be read by Arduino.
the SIM800L RX and the Microcontroller’s digital pin Given a value of R L , Power Supply Voltage, and output
10, and 2.2kilo ohms resistor between SIM800L RX voltage, Rs (sensor resistance) could be derived. Based
and GND [18], [19]. By applying the voltage divider on the chart provided in the MQ6 datasheet, figure 3,
rule and measuring the input voltage of the micropro- RS in clean air under given temperature and humid-
cessor (Arduino) to be equal to 4.85V, the voltage out- ity is a constant which is the "initial" resistance of the
put of the SIM module is calculated thus: sensor named R0 . R0 of the resistor could be derived
from Rs . The main job of the calibration is to calculate
R1 the R0 by sampling and averaging the readings when
Vout = × Vin (1)
R1 + R2 the module is placed in the clean air. Once the R0 is
derived, the concentration of target gas could be calcu-
V − out =
4.7
× 4.85 (2) lated by using the Rs /R0 ratio as the input. To achieve
4.7 + 2.2 more accuracy, a segmented look-up table should be
used. However, in the demonstration, a linear formula
V − out = 3.3V (3) is used as an approximation to the original curve [21].
The value of R0 is the value of resistance in fresh
4. Design air and the value of Rs is the value of resistance in gas
Figure 1 (an integrated hardware design drawing) concentration. First you should calibrate the sensor by
shows the device that detects the leakage of cooking gas finding the values of R0 in fresh air and then use that
(LPG) and alerts the user on the current danger. value to find Rs using the formulae:
For the microcontroller to interface the sensor,
alarm, and the LCD, it has to be programmed. Figure
2 shows the LPG leakage detector software flowchart. Resistanceo f sensor ( Rs ) : Rs = (Vc /VRL − 1) × R L
The LPG leakage detector starts and initializes, checks (4)
the quantity of gas. If the quantity of gas is less than
200ppm, the led and the buzzer are switched off. If ADC − VC
the quantity of gas is greater than 200PPM then, gas VRL = (5)
1023
Proceedings of the 2020 Sustainable Engineering & Industrial Technology Conference
C7-4 P. A. Okonkwo et al.
Table 1: Technical data of MQ6 sensor [22][23][19]
Parameter Value
High Sensitivity LPG, iso-butane, propane
Working Voltage 5V
Heater Resistance 33Ω
Heating Consumption 0.75 W
Related Humidity 95%
Sensing Resistance 10 kΩ - 60 kΩ
(200 - 10000 ppm)
Gas Sensing Layer SnO2
Preheat Time over 24 hours
Table 2: Various kinds of gas that can be detected by a
certain sensor [12]
Sensor Content
MQ 2 H2 , LPG, CH4 , CO, Alcohol, Smoke,
Propane, Air
MQ 3 LPG, CH4 , CO, Alcohol, Benzine,
Hexane, Air
MQ 6 H2 , LPG, CH4 , CO, Alcohol, Air
MQ 7 H2 , LPG, CH4 , CO, Alcohol, Air
MQ 8 H2 , LPG, CH4 , CO, Alcohol, Air
MQ 135 Alcohol, NH4 , CO2 , Air
MQ 137 NH3 , O2 , C2 H6 O, Air
MQ 138 CH4 , CO, Alkohol, Propane, Benzine,
n-Hexane, Air
Figure 2: the software flowchart for LPG leakage detector
Each sensor has a graph datasheets provided by the
manufacturer, which has X axis for mg/L or PPM value
and Y axis for the ratio of Rs and Ro . In this development,
the ratio value has the main role in determining the
appropriate PPM or mg/L value based on the datasheets
given
The graph tells us the concentration of a gas in part
per million (PPM) according to the resistance ratio of
the sensor (Rs /R0 ). Rs is the resistance of the sensor
that changes depending on the concentration of gas. R0
is the resistance of the sensor at a known concentration
without the presence of other gases, or in the fresh air.
For air, Rs /R0 = 9.8 for MQ6 gas sensor. Table 1
shows some technical data of MQ6 gas sensor whereas
table 2 shows some various kinds of gas that can be de-
tected by certain sensors.
Figure 3: Mq6 Gas Sensor Datasheet; Source: [14]
5. Analysis of the Device Performance
The fabricated device when tested for its perfor-
mance gave a positive result. The device detects the
concentration of LPG gas leakage in the air if it exceeds
a safety level and then responds by sending GSM mes-
sages to the user through the use of SIM8000L mod-
ule. The LED and buzzer are activated to alert the user
and the device displays the message on the LCD. Fig.4
shows the final device after construction, but with the
power supply switched off.
Figure 5 shows the device under test. The pre-set
critical value of the gas concentration is 200 PPM but
the gas concentration detected by the gas sensor was
9 PPM, hence it has not met the threshold for trig-
gering an alarm. The buzzer and red LED were off
as expected. The LCD display indicated “Environ- Figure 4: Device after construction
ment Safe” indicating that there is no gas leakage as
a result of insufficient quantity of LPG gas. Figure 6
Proceedings of the 2020 Sustainable Engineering & Industrial Technology Conference
Design and Construction of Cooking Gas (LPG) Leakage Detector C7-5
7. Recommendation
Human safety is a very crucial aspect in both domes-
tic and industrial settings hence, the use of gas detectors
is highly inevitable in addition to other more sophisti-
cated security systems. This device should be placed
in a cool and dry place in order to ensure a longer life
span. The sensor should not be allowed to come in
contact with high corrosive gases such as Cl2 , CO, HC,
NO, CO2 , N and HNO etc. as this will lead to the
sensor losing its sensitivity. The device should also be
Figure 5: Device under Test placed very close to the point where there is high ex-
pectation of gas leakage in order for the sensor to re-
spond actively.
References
[1] Xiao Liu, Sitian Cheng, Hong Liu, Sha Hu, Daqiang
Zhang and Huansheng Ning. (2012). A survey on Gas
Sensing Technology, Sensors 2012, 12, 9635-9665; doi:
10.3390/s120709635.
[2] Instrumentation and Control.net/msa- 2007 gas detection
handbook.
[3] Keat Ghee Ong, Kefeng Zeng and Craig A. Grimes.
(2002). A Wireless, Passive Carbon Nanotube-Based
Gas Sensor. IEEE Sensors Journal 2(2): 82-88; DOI:
10.1109/JSEN.2002.1000247.
[4] Sofian M. Kanan, Qussama M. El-Kadri, Imad A. Abu-
Yousef and Marsha C. Kanan. (2009). Semiconducting
Figure 6: Device under Test Metal Oxide Based Sensors for Selective Gas Pol-
lutant Detection. Sensors 2009, 9(10), 8158–8196;
https://doi.org/10.3390/s91008158.
[5] Edward Naranjo, Shankar Baliga and Philippe Bernascolle.
shows the device after fabrication and in a LPG en- (2010). IR Gas Imaging in an Industrial Setting. Ther-
vironment. The red LED was blinking, the buzzer mosense XXXII, edited by Ralph B. Dinwiddie and
was activated and the LCD display indicated “Environ- Morteza Safai, Proc. of SPIE Vol. 7661, 76610K;
ment Safe” and a quantity of 9999.0 PPM. This was as doi:10.1117/12.850137.
[6] W. Yi, W. Ke-Jia, W. Qi and T. Feng, "Measurement
expected since the quantity of gas had surpassed the of CH4 by differential infrared optical absorption spec-
present value of 200 PPM. troscopy," 2009 9th International Conference on Electronic
Measurement & Instruments, Beijing, 2009, pp. 1–761–1–
766.
6. Conclusion [7] Chunguang Jin, Petra Kurzawski, Andreas Hierlemann,
and, and Edward T. Zellers, "Evaluation of Multi trans-
A microprocessor device was designed to measure ducer Arrays for the Determination of Organic Vapor Mix-
LPG (propane, C3H8) gas. It can measure gas at a con- tures", Analytical Chemistry 2008 80 (1), 227-236 DOI:
centration of 200 to 10,000 ppm and the objective of 10.1021/ac071512.
this work was met since the systems work effectively. As [8] A. I. Obi, O. C. Iloeje and C. O. Anyaoha, 2020. "Design,
Fabrication and Testing of Prototype Microcontroller Based
the gas detected in the environment varied, the LCD Multipurpose Multichannel Electric Logger", in: Proceedings
displays the quantity of the LPG constantly in parts per of the second NIEEE Nsukka Chapter Conference on Sus-
million (PPM). With the gas leakage below the preset tainable Infrastructure Development in Developing Nations,
critical value, the red LED was off and the LCD dis- 26th - 29th February, 2020, Vol. 1, No. 2, 44 – 50.
played "Environment safe" indicating that there is no [9] Arduino cc. "Arduino and Genuino Products Overview".
[10] Edward Hughes, "Hughes Electrical and Electronic Technol-
leakage of gas. With the gas detected above the pre- ogy", Revised By John Hiley, Keith Brown And Ian Mckenzie
set critical value, the red LED was blinking and the Smith, Pearson Prentice Hall, Tenth Edition, 2008.
LCD displayed "Environment unsafe" indicating that [11] Thomas G. Beckwith, N. Lewis Buck and Roy D.
there is leakage of gas with the buzzer raising an alarm Marangoni. "Mechanical Measurements" Addison-Wesley
Publishing Company, Inc. third edition, 1982.
by beeping. The detector is of low cost of base unit [12] Shoffi Izza, Sabillaa, Riyanarto Sarnoa, and Joko Siswan-
price of about 7000.00 as the component that goes into torob "Estimating Gas Concentration using Artificial Neu-
making the detector can be locally sourced and readily ral Network for Electronic Nose", 4th Information Systems
available. If this is done with mass production, then the International Conference 2017, ISICO 2017, 6-8 Novem-
ber 2017, Bali, Indonesia, Procedia Computer Science 124
detector can even be of lower cost and would be easily (2017) 181–188.
affordable and competitive in the market. This price [13] B. L. Theraja, "Basic Electronics Solid State", S. Chand &
makes the device applicable to households. This sys- Company Ltd. Ram Nagar, New Delhi, Fifth Edition, 2009.
tem would be of great importance in domestic as well [14] https://en.wikipedia.org/wiki/Buzzer
[15] Holger Regenbrecht, Joerg Hauber, Ralph Schoenfelder, and
as industrial settings to detect the leakage of LPG and Andreas Maegerlein. "Virtual Reality Aided Assembly with
alert people on an impending fire incident since LPG is Directional Vibro-Tactile Feedback", in: Proceedings of the
highly inflammable. This can go a long way in helping 3rd International Conference on Computer Graphics and In-
to save human life and properties. Working capacity teractive Techniques in Australasia and Southeast Asia 2005,
Dunedin, New Zealand, November 29 - December 2, 2005;
of the device was proved with a number of tests under DOI: 10.1145/1101389.1101464.
real conditions (in a service installation for gas installa- [16] https://www.factoryforward.com/sim800l-gsm-module-
tions). arduino-commands-library/
Proceedings of the 2020 Sustainable Engineering & Industrial Technology Conference
C7-6 P. A. Okonkwo et al.
[17] https://github.com/stephaneAG/SIM800L/blob/master/README.md
[18] https://cdn.sparkfun.com/datasheets/Sensors/Biometric/MQ-
6% 20Ver1.3% 20-% 20Manual.pdf
[19] https://www.sparkfun.com/datasheets/Sensors/Biometric/MQ-
6.pdf
[20] https://rees52.com/diy-modules/1425-testing-a-mq-6-
gas-sensor-interfacing-with-arduino-uno-kt8
[21] https://study.com/academy/lesson/linear-approximation-
in-calculus-formula-examples.html
[22] Nedyalko T. Katrandzhiev and Nikolay N. Karnobatev,
"Elaboration of a Microprocessor Unit for Gas Measurement
with Sensor Mq-6", Scientific Works of University of Food
Technologies 2016 Volume 63, Issue 2.
[23] https://www.mybotic.com.my/products/MQ-6-MQ6-Gas-
Sensor-Module-(Liquefied-Petroleum-Gas-LPG–Butane
Proceedings of the 2020 Sustainable Engineering & Industrial Technology Conference
View publication stats
