Department of EEE

PROJECT REPORT

Project name : Smoke Detection System

Course no. : EEE 2211

Course name : Measurement and Instrumentation

Submitted by :

14.02.05.134 - A.O.M. Shamsuddoha

14.02.05.136 - Shadab Sadman

14.02.05.157 - Muid Hasan Anik

14.01.05.131 – Mustafizur Rahman

SMOKE

DETECTION

SYSTEM

ABSTRACT A Smoke Detector is a fire protection device that

automatically detects smoke/gases and also gives

us warning to be aware of it, with some protection

system to handle the situation. Many fire accident

occurs in our surrounding due to absence of human

in the right place at the right time. That is the

importance of the project, it can minimize such

accidents. Thus it got immense importance in our

practical life.

Equipment used :

1. Arduino uno

2. Gas sensor : MQ-2

3. Temperature sensor : LM-35

4. Servo Motor

5. Buzzer Alarm

6. LED

7. 9V DC Battery

8. 7805 IC

9. Gas lighter (for testing purpose)

Some Instrument Details : (in short)

1. MQ-2 Gas Sensor :

Among various types of MQ series gas sensors we selected MQ-2 for their wide

detecting scope, fast response and High sensitivity. They are suitable for

detecting LPG( Liquified Petroleum Gas), i-butane, propane, methane ,alcohol,

Hydrogen, smoke. The gas sensor is mainly composed of tin dioxide on a

ceramic base. The resistance of the sensor varies depending on the

concentration of the reducing gases on the air. We used the module here,

here se sor’s pi s are o e ted as eed i ter ally ith resistance. Four

pins are outside there, VCC (with 5V dc), GND (with Arduino gnd), A0 (from

here e took output, o e ted it to ardui o A a d D e did ’t use . The

power led(red) turns on when it powered, and the Dout led (green) turns on

when it detects gas.

2. LM-35 temperature sensor :

The LM35 series are precision integrated-circuit temperature sensors, whose

output voltage is linearly proportional to the Celsius (Centigrade) temperature.

The LM35 does not require any external calibration or trimming to provide

typi al a ura ies of ± ⁄ °C at roo te perature a d ± ⁄ °C o er a full − to +150°C temperature range.

Other Features :

I. Calibrated directly in ° Celsius (Centigrade)

II. 0.5°C accuracy guaranteeable (at +25°C)

III. Suitable for remote applications

IV. Less tha μA urre t drai

V. Low self-heating, 0.08°C in still air

3. 7805 IC

We needed this component here to provide extra 5V dc voltage. Because

when we connected two sensors in parallel, current is also distributed in

two parallel paths. As a result LM-35 sensor receives negligible

current(because of POT on the MQ-2 it draws most the current) and it

does ’t ork properly. For this e eed to use IC to pro ide the shortage of current through LM-35 as required. Here capacitors are for

redu i g ripple oltage, though it’s ot mandatory to use(we have skipped

this without any trouble). An extra 9V battery is needed to operate the IC.

4. Servo Motor :

A servomotor is a rotary actuator or linear actuator that allows for precise

control of angular or linear position, velocity and acceleration. It consists of

a suitable motor coupled to a sensor for position feedback. In our project

use of servo motor is quite limited in fact it is optional, we need this for

protection purpose to on and off the water pump switch.

Circuit Diagram :

Image view :

Working Principle :

We have used two different sensors : gas sensor and temperature sensor. The

MQ-2 gas sensor senses smoke (due to fire) and gas leakage ( like methane,

LPG etc. in our kitchen or factory). And the LM-35 temperature sensor is for

detecting temperature rise due to fire. At first our Arduino UNO will get

information from the two sensors, and then it will compare the values

according to the condition given in the code. If the values are under the

tolerance level everything will be normal. But if either the temperature or the

concentration of gas rises above the condition then the buzzer will be alarmed.

Also if temperature or gas increases further it will operate a servo motor

whose work will be to ON the switch of a water pump to control the fire by

spreading water over the place(we could not arrange the water system part in

our project). We programmed this device that is implemented on the Arduino-

Uno (ATmega328p) and the value of the concentration of the smoke is given

high so that normal smoking gas will not be the reason of the device alarm.

This device is designed such as only real fire occurrence will be the reason for

this device alarming. After the device alarms, the servo motor shaft will

automatically rotate half of a cycle or 180 degree to switch on the water pump

or water spray. Thus this device can eradicate fire. Gradually when the

condition is under control or back to normal again the servo will switch OFF the

pump and also the buzzer will be stopped.

Code :

#include <Servo.h>

Servo myservo;

int buzz = 10;

int gas = 0;

int smoke = A0;

int temp = 0;

int lm35 = A1;

void setup()

{

myservo.attach(3);

pinMode(buzz,OUTPUT);

pinMode(smoke,INPUT);

pinMode(lm35,INPUT);

Serial.begin(9600);

}

Microcontroller (Arduino UNO)

Get info./values from gas sensor

Get info./values from temp.

sensor

Compere values according to

condition/Code

Operate the buzzer and

servo

void loop()

{

temp = analogRead(lm35);

int celsius = temp/2 - 5;

Serial.println(celsius);

gas = analogRead(smoke);

Serial.println(gas);

if(celsius>40 || gas>190)

{

if(celsius>45 || gas>250)

{

digitalWrite(buzz,HIGH);

delay(200);

digitalWrite(buzz,LOW);

delay(200);

int pos = 180;

myservo.write(pos);

delay(5);

}

else

{

int pos = 0;

myservo.write(pos);

delay(5);

digitalWrite(buzz,HIGH);

delay(800);

digitalWrite(buzz,LOW);

delay(800);

}

}

else

{

digitalWrite(buzz,LOW);

delay(1000);

}

}

Troubleshooting :

1. When we connect both the sensors with Arduino 5V and GND in parallel,

our LM-35 was not responding as it was responding individually(correctly)

without the MQ- gas se sor, due to urre t shortage i it’s branch. For

solving the problem we used 7805 regulator IC.

2. In different environment we need to calibrate the MQ-2 gas sensor

separately either y adjusti g the alue of it’s POT or ha ge the ra ge of it’s alue to operate i the CODE. This is e ause o centration of gases it

sense, are not same in every place or environment; so it gives values of

different ranges in different places.

3. We also faces difficulties calibrating the LM- to sho it’s readi g i Celsius scale.

Application :

1. This project can be used commercially as a security purpose device that will

detect fire and gas leakage in our kitchen or factory, mall, museum, hotels,

restaurants, laboratory etc.

2. In many home in our city there occur accident due to gas leakage in the

kitchen, this project can be used to minimize this occurrence .

3. On Every Garments Factory, there is a chance of accident for the occurrence

of fire. That is why this device is necessary to use.

Discussion :

Though smoke detection system is quite a simple project but it has immense

importance and necessity in our practical life. We programmed this device that

is implemented on the Arduino-Uno (ATmega328p) and the value of the

concentration of the smoke is given high so that normal smoking gas will not

be the reason of the device alarm. We can also add some further

improvement in this project. We are planning to use the dc water pump

without servo directly with the Arduino for more reliable and fast response.

And also we want to add a GSM module here for sending sms to the owner

when smoke is detected. It will be beneficial when no one at home or at a

vacant place.