Therft alert system

THERFT ALERT SYSTEM

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.

BLOCK DIAGRAM:

Power supply

relay

Ir sensorUsing lm358

buzzerload

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.

HARDWARE DESCRIPTION:-

POWER SUPPLY IR SENSOR THEFT DECTETOR CIRCUIT RELAY

POWER SUPPLY:-

IR SENSOR:-

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).

RELAY 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.

WOKING

THEFT DECTETOR:-

R6270

R71.5K

3

21

84

U2:A

LM358

R8

1.0K

D12LED-RED

ADVANTAGES:-

Easy hardware Low costing Easy to used For home & office

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.