THEFT ALERTSYSTEM USING IR SENSOR MODULE

1. THERFT ALERT SYSTEM

2. INTRODUCTION:
 In our project we are using ir sensor based on lm358 & relay, buzzer for the
theft detection.
 IR sensor module responds to only 38 kHz pulsed infrared rays. It will not
sense continuous IR ray from the IR LED. So a transmitter circuit(as one in TV
remote handset) based on lm358 IC is required. Any standard transmitter
circuit based on lm358 IC can be used. But its output should be 38kHz exactly.
That is when IR rays are not available.

3. BLOCK DIAGRAM:
Power supply
relay
Ir sensor
Using lm358
buzzer
load

4. WORKING PRINCPLE:-
 Two Infrared LEDs always emit continuous infrared beam to the Photodiode.
The IR LEDs and Photodiode are placed on the opposite frames of the door
and properly aligned. Resistor R1 is the current limiter giving around 70 mA
current through the LEDs which is necessary to increase the output of IRLEDs.
IC1 is designed as Current to Voltage converter with the reverse biased
photodiode connected to its inverting input. The non inverting input is
directly grounded.
 Resistor R2 and VR1 forms the feedback loop to adjust the sensitivity of the
IC. Normally the Photodiode generates a small current by accepting the
energy from the infrared Beam. This tiny current will be amplified by IC1 and
gives a high output. This forward biases T1 and it conducts. The emitter
current from T1 keeps T2 off since it is a PNP transistor. Since T2 is off,
Buzzer remains silent. In short, in the standby mode, LED glows indicating the
active state of circuit and buzzer remains off.

5. HARDWARE DESCRIPTION:-
 POWER SUPPLY
 IR SENSOR
 THEFT DECTETOR CIRCUIT
 RELAY

6. POWER SUPPLY:-

7. IR SENSOR:-

8. Working:-
 IR stands for “Infra Red”. Infrared detectors/sensors are transducers of
radiant energy.IR Sensor is a sensor that sends and detects IR
Radiation/Signals. Infrared radiation is the portion of electromagnetic
spectrum having wavelengths longer than visible light wavelengths, but
smaller than microwaves, i.e., the region roughly from 0.75µm to 1000 µm
is the infrared region. Infrared waves are invisible to human eyes. The
wavelength region of 0.75µm to 3 µm is called near infrared, the region
from 3 µm to 6 µm is called mid infrared and the region higher than 6 µm
is called far infrared. (The demarcations are not rigid; regions are defined
differently by many).

9.  A relay is an electrically operated
switch. Current flowing through
the coil of the relay creates a
magnetic field which attracts a
lever and changes the switch
contacts. The coil current can be
on or off so relays have two switch
positions and they are double
throw (changeover) switches.

11. THEFT DECTETOR:-
R6
270
R7
1.5K
3
2
1
84
U2:A
LM358
R8
1.0K
D12
LED-RED

12. ADVANTAGES:-
 Easy hardware
 Low costing
 Easy to used
 For home & office

13. CONCLUSION:-
 This project presents the Theft alert system for home office and it is
designed, implemented and tested. Here in this Experimental work has been
carried out carefully and we know how ir sensor, relay work. The result shows
that higher efficiency is indeed achieved using the embedded domain.