This project uses a temperature sensor to detect the occurrence of a fire and in that case uses a GSM module to send a text alert to the user's phone number.

1. MINI PROJECT
GSM BASED SMS ALERT FIRE ALARM
SYSTEM USING ARDUINO

2. Overview
So what is this project? What does it do?
Basically this is a fire monitoring system,
which detects if there is a fire by measuring
the surrounding temperature. If it goes
beyond a certain critical point, it alerts the
user by sending a text alert to the phone
number of the user so that he or she may be
able to prevent any serious damage.

3. Before we start with the project itself, let’s see what led us to
take up this challenge to make this fire alarm system.
• Smoke alarms provide a critical early warning of fire, allowing
additional time to escape. National estimates of reported fires derived
from the National Fire Incident Reporting System (NFIRS) and the
National Fire Protection Association’s (NFPA’s) fire department survey
show that in 2009-2013, fires in homes with no smoke alarms caused an
average of 940 deaths per year (38% of home fire deaths). An
additional 510 people per year (21% of home fire deaths) were fatally
injured in fires in which smoke alarms were present but failed to
operate.
• Hardwired smoke alarms were more likely to operate than those
powered solely by batteries.
• The death rate per 100 reported fires was more than twice as high in
homes with no or no working smoke alarms (1.18 deaths per 100 fires)
as it was in fires with working smoke alarms (0.53 deaths per 100
fires). The lowest fire death rates were seen in homes with hardwired
smoke alarms and sprinklers.

4. So, we see that fire alarm systems are very much
in need even in this technologically advanced
era.
Speaking of technological advancements, what
comes to the mind first?
Smartphones!
So, why not integrate a fire alarm system with
our smartphones? That way the system can
warn us anytime there is a fire regardless of
wherever we are at the moment. We do not
have to be physically present at the site of the
fire to prevent it! That is worderful! Now let’s
get to the project itself.

5. Equipments used
• Arduino Uno
• GSM Module
• 16x2 LCD Display
• LM 35
• Vero Board
• 10k potentiometer
• 12V AC Adapter
• Resistors
• Wires and jumper cords

6. Circuit Diagram

7. The main elements of the circuit
• The Arduino
• LM 35
• The GSM Module
• The LCD display

8. The Arduino
It is an open-source microcontroller based kit for building digital
devices and interactive objects that can sense and control objects in
the physical world. It is based on microcontroller board designs,
manufactured by several vendors, using various microcontrollers.
These systems provide sets of digital and analog I/O pins that can
be interfaced to various expansion boards ("shields") and other
circuits. The boards feature serial communications interfaces,
including USB on some models, for loading programs from personal
computers. For programming the microcontrollers, the Arduino has
a specific software associated with it which provides an integrated
development environment (IDE) based on the Processing project,
which includes support for the C and C++ programming languages.
In this project this is the main workhorse. This controls the entire
circuit and makes all the decisions.

10. LM 35
• The LM35 is an integrated circuit sensor that can be used
to measure temperature with an electrical output
proportional to the temperature (in oC)
• Why Use LM35s To Measure Temperature?
» We can measure temperature more accurately than a using a
thermistor.
» The sensor circuitry is sealed and not subject to oxidation, etc.
» The LM35 generates a higher output voltage than
thermocouples and may not require that the output voltage be
amplified.

11. What Does An LM35 Look Like?
Here it is.

12. • What Does an LM35 Do? How does it work?
» It has an output voltage that is proportional to the Celsius
temperature.
» The scale factor is .01V/oC
» The LM35 does not require any external calibration or trimming
and maintains an accuracy of +/-0.4 oC at room temperature
and +/- 0.8 oC over a range of 0 oC to +100 oC.
» Another important characteristic of the LM35 is that it draws
only 60 micro amps from its supply and possesses a low self-
heating capability. The sensor self-heating causes less than
0.1 oC temperature rise in still air.
• The LM35 comes in many different packages, including
the following.
» TO-92 plastic transistor-like package,
» T0-46 metal can transistor-like package
» 8-lead surface mount SO-8 small outline package
» TO-202 package. (Shown in the previous slide)

13. The GSM Module
This module is responsible for the communication part of the
circuit. It takes information from the Arduino where to send
information and what information is to be sent. It uses a GSM SIM
card for communication purposes. It is basically just a MODEM
which uses serial communication to interface with and need Hayes
compatible AT commands for communication with the Arduino.
The alert message and the phone number of the recipient is given
by the user through the Arduino code. As soon as fire is detected an
SMS will be sent to the recipient’s phone number from the SIM card
inserted into the module.

14. SIM Card slot
Antenna
This is what it looks like

15. The LCD Display
This is used for displaying the current status of the circuit and the
actions taken by the circuit.

16. Now let’s get to the working…

17. • The LM 35 continuously monitors the
temperature and sends that information to
the Arduino. The temperature data is sent in
the form of voltage. The scale factor of the LM
35 is 0.01V/ºC.
• If a fire takes place, the temperature of the
surrounding starts increasing. As soon as the
temperature crosses a threshold value, the
Arduino sends a signal to the GSM Module to
do its job.

18. • The GSM Module sends a text message to the
user’s phone number from the SIM Card that
is inserted into the module. The code run on
the Arduino determines which number to
send the message to, how many times the
message needs to be sent, and some other
details.
• Now that the user has been alerted, the job of
the system is over. It is now up to the user to
take preventive measures.

19. Setbacks and Modifications
• No project is a success without setbacks. In
this project, the GSM Module proved to be a
major problem as during the testing, due to
unregulated current fluctuations, the chip
burned out and stopped working.
• So, we had to modify the project a little bit,
due to time constraints, we ultimately ended
up making just a simple fire alarm with an
alert speaker. To do this, we had to modify the
Arduino code for the circuit to function
without the GSM Module.

20. The modifications to the code are as follows:
• We created an extra function Alert() which is
called as soon as “fire” is detected, which tells
the speaker to sound the alarm.
• As soon as the surrounding temperature
restores back to normal, the condition in the
code to check whether fire has occurred or
not, becomes false and the noTone() function
is called to stop the speaker.

21. The modified Arduino Code
#include <SoftwareSerial.h>
#include<LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
SoftwareSerial mySerial(9, 10);
int sensor=A1;
float temp_read,Temp_alert_val,Temp_shut_val; int Fire_Set;
void setup()
{
pinMode(sensor,INPUT);
mySerial.begin(9600);
Serial.begin(9600);
lcd.begin(16,2);
delay(500);
}
void loop()
{
CheckFire();
CheckShutDown();}

22. void CheckFire()
{
lcd.setCursor(0,0);
lcd.print("Fire Scan-ON");
Temp_alert_val=CheckTemp();
if(Temp_alert_val>45)
{
Alert();
lcd.setCursor(0,1);
lcd.print("Fire Alert!");
Fire_Set = 1;
}
}
float CheckTemp()
{
temp_read=analogRead(sensor); // reads the sensor output (Vout of LM35)
temp_read=temp_read*5; // converts the sensor reading to temperature
temp_read=temp_read/10; // adds the decimal point
return temp_read; // returns temperature value in degree celsius
}

23. void Alert()
{
tone(8,2637);
}
void CheckShutDown()
{
if(Fire_Set==1)
{
Temp_shut_val=CheckTemp();
if(Temp_shut_val<28)
{
noTone(8);
lcd.setCursor(0,1);
lcd.print("Fire Shut!");
Fire_Set=0;
}
}
}

24. The Realised Project

25. The Modified Realised Project

26. Here is an animation showing the
working of the project…

27. The GSM Module
receives info from the
Arduino and sends
the text alert to the
user’s phone number
The Arduino
now tells the
display to its
job!
LM 35
In case of a fire,
The LM 35 senses a temperature
rise…
The LM 35
now passes
the info on to
the Arduino
The Arduino then
Processes the info
and tells the other
components to do
their respective jobs!
Fire
Detected!
SMS Sent!

28. END OF PROJECT