This document describes an RF-based home security system consisting of various sensors, an encoder, transmitter, receiver, and decoder. The system detects intruders via PIR, gas, fire, and light sensors and transmits encoded signals to a receiver using a 433MHz RF transmitter. When the receiver detects intruder signals, it triggers an alarm to alert users and can activate additional security systems through a relay switch. The wireless system provides an affordable way to monitor a home and deter crime without wires.

1. RF Based
Home Security System
Presented By:
Keshari Nandan (1113331085)
Md. Aamir Khursheed (1113331106)
Manu Singh Gaur (1113331098)
Rohit Shukla (1113331161)
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Submitted to:
Mr. Yogesh Kr. Verma
(Asst. Professor ECE)

2. Contents
1. Introduction
2. Block Diagram
3. Power Supply
4. Operational Amplifier
5. PIR Sensor
6. Gas Sensor
7. Fire Sensor
8. LDR
9. RF Encoder
10.RF Transmitter
11.RF Receiver
12.RF Decoder
13.Working
14.Advantages
15.Applications
16.Conclusion
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3. Introduction
The fear of theft and burglary always annoys many people. When
lock and keys become less safe, one can seek the help of electronic
security systems.
Such a portable security system is described here.
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4. Block Diagram 4

5. Power Supply
1. Transformer: An step down
Transformer is used which convert
240V AC Power supply to 12/24V
AC.
2. Diode(1N4007): Here four diode are
used. During the +ve cycle diode
D1 and D2 is conducting and
during the –ve cycle diode D3 and
D4 is conducting.
3. Smoothing Capacitor: Here
smoothing capacitor is used to
reduce the ripple.
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6. 6
Op-Amp(Operational Amplifier)
Here two op-amp are used(Because we are using 4 sensor and one
op-amp has the capacity to handle only two sensor).
Power Supply: Min: 3 Volt
Max: 32 Volt
Operating Temperature: Min: 0 C
Max: 70 C
Input Current: Max: 50 mA

7. 7
Passive Infrared Sensor(PIR)
PIR Sensor are used for tracking the movement.
If any moving body passes in front of the sensor
then sensor is activated and send a DC signal to the
out PIN.
PIR Sensor are having the two slot and these slots
are continuously sensing the temperature. If any
body passes to it the for a while the two slots are at
different temperature thus sensor turn on the output
PIN.

8. 8
Passive Infrared Sensor(PIR)
PIR Sensor are used for tracking the movement.
If any moving body passes in front of the sensor
then sensor is activated and send a DC signal to the
out PIN.
PIR Sensor are having the two slot and these slots
are continuously sensing the temperature. If any
body passes to it the for a while the two slots are at
different temperature thus sensor turn on the output
PIN.

9. 9
Gas Sensor
Gas sensor is used to sense the gases. It protect from
leakage of CNG gas(If security system is used to protect
the vehicle) or any harmful gas used by the thief during
the theft.
Gas sensor has SnO2 (Tin Oxide as sensing material),
heating plate and electrodes. When any gas comes in
contact with sensor then SnO2 start heating and
becomes conductor and two electrode becomes short
circuited and signal is send to the destination.

10. 10
Gas Sensor
Gas sensor is used to sense the gases. It protect from
leakage of CNG gas(If security system is used to protect
the vehicle) or any harmful gas used by the thief during
the theft.
Gas sensor has SnO2 (Tin Oxide as sensing material),
heating plate and electrodes. When any gas comes in
contact with sensor then SnO2 start heating and
becomes conductor and two electrode becomes short
circuited and signal is send to the destination.

11. 11
Fire Sensor
Fire sensor is used to detect fire flame
around it.
Fire sensor uses a comparator into it.
one terminal of fire sensor is set by the
potentiometer and other is connected
by sensor terminal and by default both
terminal are at same potential.
When sensor senses heat near it then
the voltage of one terminal get
changed and comparator output
becomes greater than zero and signal
is send to the destination.

12. 12
Light Detecting Resistor(LDR)
Light Detecting Resistor is used to detect the light in
night.
LDR has coating of conducting material(Electrode)
and it is separated an insulator material(only in
absence of light) known an Cadmium Sulphide.
When light is incident on the Cadmium Sulphide then
it become an conducting material and both the
electrode becomes short circuited.

13. 13
Light Dependant Resistor(LDR)
Light Dependant Resistor is used to detect the light in
night.
LDR has coating of conducting material(Electrode)
and it is separated by an insulator material(only in
absence of light) known an Cadmium Sulphide.
When light is incident on the Cadmium Sulphide then
it becomes a conducting material and both the
electrode becomes short circuited.

14. 14
RF Encoder
HT12E – 18DIP is an encoder and used to encode signal
coming from the op-amp and send to the transmitter.
HT12E has:
18 PIN
2.4-12 operating voltage.
low power dissipation.
High noise immunity.
38kHz for infrared transmission.
It has 8 address line and 4 data line.
It can accept 4 bits parallel data from its input terminal.
Output of serial data is fed into external RF Transmitter.

15. 15
RF Transmitter
RF Transmitter is used to transmit the incoming serial signal to the
receiver.
RF Module uses the frequency of 433 MHz and Amplitude shift
keying modulation.
Range of 433MHz RF Transmitter is 100 meters in standard
conditions.
Supply Voltage is 3 ~ 6 Volt.
Output Power is 4 ~ 12 dBm.

16. 16
RF Receiver
RF Receiver is used to received the incoming RF
Signal and convert back to the serial signal and
send to the decoder.
RF Receiver has low power consumption and its
require 5 Volt and 3.5 mA current to run.
It also operate at the frequency of 433 MHz
with the sensitivity of 105 dBm.

17. 17
RF Decoder
RF decoder takes the serial signal coming from receiver and
convert it into electrical signal and further it send this
electrical signal to Alarm.
RF Decoder has 4 data line and 8 address line. It is an 18 PIN
IC.
It has low power dissipation and high noise immunity CMOS
Technology.
It is capable of decoding 12 bit of information.

18. 18
Working
The system has two main parts: an intruder sensor cum transmitter and a receiver. The intruder sensor
reacts to light, fire, gas and mechanical movements. When the sensor detects a disturbance, the
transmitter gets triggered and begins to send wireless signals.
The receiver placed away from the transmitter receives the signals and produces an audio alarm. At
the same time, a relay switch is turned on so that other security systems can be energized through
this relay.

19. 19
Advantages
 Track and alerts from unwanted and suspicious movements.
 Warn us against hazardous fire.
 The system has DC operated function with portable receiver.
 Deters crime and protect valuables.

20. 20
Applications
 Can be used in locker.
 Can be used to protect costly garments.
 Can be used to protect vehicle against theft.
 Securance System is the company which is using the same concept to protect ATMs against theft.

21. 21
Conclusion
In this project we implemented Home security system comprising Wireless alerts using RF signals
as communication standards. The hardware equipment is tested and result is obtained. This
project is cost effective. Implementation of this project in present day will effectively provide a
peace of mind to the residents. This project can be implemented both in apartments and
General stores as well.

22. 22
Thank You