Measurement and instrumentation project

1. OBAFEMI AWOLOWO UNIVERSITY,ILE-IFE,NIGERIA.
DESIGN OF IOT BASED FIRE ALARM SYSTEM
A PROJECT REPORT SUBMITTED
BY
Group 9, 300L Students Of Electronic & Electrical Engineering As One of The Assessment
Item For EEE310 (Measurement & Instrumentation I) Course Unit.
S/N GROUP MEMBERS MATRIC NO
1 AJAYI PRAISE EEG/2016/009
2 CHUKWUETOO JOY CHIKAODILI EEG/2016/019
3 IBEH CHIBUNA KENNETH EEG/2016/029
4 KPEREGBEYI AYIRI LESLIE EEG/2016/039
5 OKWUNZE CHIAGOZIE KELVIN EEG/2016/049
6 OMOTAYO OLUWATOBI M EEG/2016/059
7 AKPANOWO EDIDIONG JOHN EEG/2016/089
8 OTI JOEL CHUKWUEMEKA EEG/2016/099
9 ADEBIYI TEMITAYO MOSES EEG/2017/109
10 GABRIEL KAYODE MOSES EEG/2017/119
OCTOBER, 2019.

2. INTRODUCTION
This report has proposed an internet of things (IoT) based fire alarm monitoring and control
system best suited for industrial and home applications. This research work focused on using the
low cost ESP8266 Wi-Fi modules and MQTT to create collaborative awareness and ubiquitous
services for static IoT smart home. Collaborative-aware service makes devices interact
automatically without human intervention while ubiquitous service makes collaborative aware
service available anywhere and anytime. Fire is the major cause of accidents claiming valuable
lives and property. The chemical reaction between carbon-based materials in presence of oxygen
generates flammable vapor causing a steady rise in temperature and results in a fire. The major
characteristics of fire are it extends exponentially with time. Hence, timely detection of fire is
critical for avoiding a major accident. In this report, fire alarm system is integrated with IoT
platform. It can sense flame, the rise in temperature, and send it to a far-away control station
through WIFI to generate needful instructions for the actuator. The system is a monitoring and
control system. The sensors monitor the physical quantities such as temperature, flame and give
its output as voltage.

3. FIRE ALARM SYSTEM MODEL
The fire alarm system comprises of three major subsystem: (1) ESP866 which is basically a
microcontroller system that is responsible for all decision making process along with that (2)
sensor subsystem that has sensors sense the physical quantities to identify fire followed by
comparator, actuator and Wifi Module. The functional block diagram of conventional fire alarm
system is shown below.
A set of sensors are deployed in various zones to identify the location of the fire that comprises
of the temperature sensor and flame sensor. Fire Outbreak results significant increase in
temperature and percentage of carbon dioxide and carbon monoxide present in the atmosphere.
The temperature sensor used is LM35. The LM35 series are precision integrated-circuit
temperature devices with an output voltage linearly proportional to the Centigrade temperature.
The LM35 device does not require any external calibration or trimming to that provide typical
accuracies of ±¼°C at room temperature and ±¾°C over a full -55°C to
150°C temperature range. Flame sensor has photodiode to detect the light and op-amp to control
the sensitivity. It is used to detect fire and provide HIGH signal upon the detection. ESP866
reads the signal and provides alert by turning on buzzer. Flame sensor used here is an IR based
flame sensor. The ESP866 is basically a microcontroller system that takes sensor output as input.
The sensor outputs voltages are analog and digital in nature and are compared with a pre-
determined threshold by the comparator. The comparator outputs are either ‘1’ or ‘0’ that is
being given input to the processor. After receiving and analyzing the information, it provides
necessary instruction to the actuators. The actuators of the system are buzzer alarm.
TEMPERATURE
SENSOR
FLAME
SENSOR
Comparator
Comparator
ESP866
Buzzer
Alarm
Wifi
Module
MQTT
PLATFORM

4. COMPONENT USED
ESP8266-The ESP8266 is a System on a Chip (SoC), manufactured by the Chinese company
Espressif. It consists of a 32-bit micro controller unit (MCU) and a Wi-Fi transceiver. It has 11
GPIO pins* (General Purpose Input/Output pins), and an analog input as well. And on top of
that, you get Wi-Fi communication, so you can use it to connect to your Wi-Fi network, connect
to the Internet, host a web server with real web pages, let your smartphone connect to it, etc ...
The possibilities are endless! It's no wonder that this chip has become the most popular IOT
device available. The Internet of Things (IoT) is a system of interrelated computing devices,
mechanical and digital machines, objects, animals or people that are provided with unique
identifiers (UIDs) and the ability to transfer data over a network without requiring human-to-
human or human-to-computer interaction. The ESP8266 is a 3.3V microcontroller, so its I/O
operates at 3.3V as well. The maximum current that can be drawn from a single GPIO pin is
12mA. The ESP8266 has a single analog input, with an input range of 0 - 1.0V. The ADC
(analog to digital converter) has a resolution of 10 bits.
Monitoringthe Temperature UsingLM35- Threshold value (whichis30°C) alsobe programmedandthe
hostcan be notifiedwhentemperature isabove thisthreshold. Itisan analogand lineartemperature
sensor,whichhasa linearrelationshipbetweenoutputvoltage andtemperaturechanges(°C). Itshows
valuesinthe formof outputvoltagesinsteadof degreeCelsius.Thissensorisfullyratedfrom -55 °C to
+150 °C and withthe linearscale factorof 10mV/°C. It operatesfrom4 to 30 V,has lessthan60µA drain
currentand has lowself-heating.The inputvoltage affectstemperature measurement.Itssmallest
inputchange is0.5 °C. Whena 5V supplyisused,youhave aresolutionof 5000mV/1024 = 4.8mV.
Because the LM35 has a outputof 10mV/C the resolutionof the thermometeris10mV/4.8mV ~ 0.5ºC.
Detecting Fire using Flame sensor- The flame sensor is used to detect the fire which are in the
range of wavelength from 760nm to 1100nm and can detect fire up to distance of 100cm within
60 degrees of angle of detection. The module consists of an IR sensor, potentiometer, OP-Amp
circuitry and a led indicator. When a flame will be detected, the module will turn on its red led.
The sensitivity of this sensor is adjustable and it also has a stable performance. Every object
including the “fire” emits some amount of Infrared rays which are detected by the photodiode.
An operation amplifier is attached across the photodiode to detect the change in voltage. If the
voltage detected is zero it gives digital output “1” and if it detects some voltage in case of fire
then it gives digital output as “0”.
Control Element- The actuator of the system is buzzer alarm. The alarm makes a sound when
temperature in an environment is above the threshold value and flame is detected.

5. PROJECTDESCRIPTION
IOT Based Fire Alerting System uses two Sensors, namely, Temperature and Flame sensors.
There is an ADC convertor, which converts the analog signals received at the temperature sensor
end to digital and then transmits them to the ESP8266. The ESP8266 is programmed to turn on
the buzzer, when the temperature in the environment reach a threshold value and flame is
detected.
At the same time, NodeMCU sends the data to the Wi-Fi module ESP8266. ESP8266 is a chip
which is used for connecting micro-controllers to Wi-Fi network. ESP8266 will then the
following data to the IOT website, where, authorized people can take appropriate measure in
order to curb the fire.
a. Temperature (in Degree Celsius)
b. Flame Detection
The Pre-requisite for this IoT based fire alarming system is that the Wi-Fi module should be
connected to a Wi-Fi zone or a hotspot.

6. CIRCUIT DIAGRAM

7. CONFIGURE MQTT PLATFOFM
MQTT is one of the most commonly used protocols in IoT projects. It stands for Message
Queuing Telemetry Transport. In addition, it is designed as a lightweight messaging protocol that
uses publish/subscribe operations to exchange data between clients and the server.
Like any other internet protocol, MQTT is based on clients and a server. Likewise, the server is
the guy who is responsible for handling the client’s requests of receiving or sending data
between each other.
MQTT server is called a broker and the clients are simply the connected devices.
So:
 When a device (a client) wants to send data to the broker, we call this operation a
“publish”.
 When a device (a client) wants to receive data from the broker, we call this operation a
“subscribe”.
In this system that has a temperature sensor. Certainly, it wants to send his readings to the
broker. On the other side, a phone/desktop application wants to receive this temperature value.
Therefore, 2 things will happen:
 The device defines the topic it wants to publish on, ex: “temp”. Then, it publishes the
message “temperature value”.
 The phone/desktop application subscribes to the topic “temp”. Then, it receives the
message that the device has published, which is the temperature value.
Again, the broker role here is to take the message “temperature value” and deliver it to
phone/desktop application.

8. The same also applies to the flame sensor.
RESULTS