ANTI-BAG SNATCHING ALARMG.SRINIVASULU V.SRIKANTH

09491A04A9 09491A04A8

CONTENTS

INTRODUCTION

COMPONENTS

CIRCUIT DIAGRAM

EXPLANATION

ADVANTAGES

APPLICATIONS

CONCLUSION

INTRODUCTION

When a burglar tries to snach the bag,it sounds a loud alarm,simulating a police horn.

This will draw the attention of other passengers and the burglar will be easily caught.

In sttandby mode the circuit is provided with a lock but when a burglar tries ti snach it, the circuit turns into unlocked mode to sound a loud alarm,simulating a poloce horn.

This circuit consists of three ICs.

They are ICI CA3140(ICI),which acts as a comparator,IC2 NE555 which acts as monostable multi-vibrator and IC3  UM3561 which is a complex ROM with inbuilt oscillator.

A single stage transistor BD139 acts as loud speaker to sound a loud police horn

COMPONENTS

Resistors (all ¼-watt, ± 5% Carbon)

R1, R2, R3 = 100 KΩ

R4, R6 = 10 KΩ

R5 = 10 MΩ

R7 = 330 Ω

R8 = 220 KΩ

R9 = 1 KΩ

VR1 = 10 MΩ

Capacitors

C1, C3 = 0.0047 µF

C2 = 4.7 µF/16V

C4 = 0.01 µF

Semiconductors

IC1 = CA3140 (operational amplifier)

IC2 = NE555 (timer IC)

IC3 = UM3561 (complex ROM with an inbuilt oscillator)

T1 = BD139

ZD1 = 3.3V 500mA

Miscellaneous

SW1 = ON/OFF switch

L1 = speaker 8Ω 1W

CIRCUIT DIAGRAM

EXPLANATION

In the standby mode, the circuit is locked by a plug and socket arrangement (a mono plug with shorted leads plugged into the mono-jack socket of the unit). When the burglar tries to snatch the bag, the plug detaches from the unit’s socket to activate the alarm.

The circuit is designed around op-amp IC CA3140 (IC1), which is configured as a comparator

The output from pin 6 of IC1 is fed to trigger pin 2 of IC NE555 (IC2) via coupling capacitor C1 (0.0047 µF). IC2 is configured as a monostable.

When there is an attempt at snatching, the plug connected to the circuit de- taches. At that moment, the voltage at the inverting input of IC1 exceeds the voltage at the non-inverting input and sub- sequently its output goes low

Resistor R7 (330 ohms) limits the cur- rent to IC3 and zener diode ZD1 limits the supply voltage to IC3 to a safe level of 3.3 volts. Resistor R9 limits the cur- rent to the base of T1

The alarm tone generated from IC3 is amplified by transistor T1. A loudspeaker is connected to the collector of T1 to produce the alarm.

The alarm can be put off if the plug is inserted into the socket again. Transistor T1 requires a heat-sink.

Resistor R7 (330 ohms) limits the current to IC3 and zener diode ZD1 limits the supply voltage to IC3 to a safe level of 3.3 volts. Resistor R9 limits the current to the base of T1.

ADVANTAGES

SAFE AGAINST VALUABLE ITEMS IN BAG

SIMPLE AND HANDY

ALARM FOR EASY IDENTIFICATION

APPLICATIONS

CARRY IMPORTANT ITEMS IN BAG SAFELY

NO WORRY WHILE TRAVELLING FOR LOSS OF ITEMS IN BAG

CONCLUSION

The circuit kept in your bag or suitcase sounds a loud alarm, simulating a police horn, if someone attempts to snatch your bag or suitcase.

This will draw the attention of other passengers and the burglar can be caught red handed

QUERIES????????

THANK YOU