01-08-2010, 03:42 PM
[attachment=4051]
PRESENTED BY:
RAJLAXMI SAHA(4th YEAR EE)
ORISSA ENGINEERING COLLEGE
INTRODUCTION
COMPONENTS USED
CIRCUIT EXPLANATION
ADVANTAGES
PRECAUTIONS
CONCLUSION
INTRODUCTION
NOW-A-DAYS DESKTOP HAS BEEN REPLACED BY LAPTOP WHICH IS A DEFORMED FORM.
SO IT HAS BECOME EASIER FOR THEFT TO STEEL OUR VALUABLE LAPTOP.
TO OVERCOME THIS KIND OF STEELING A LAPTOP PROTECTOR IS REALISED,WHICH WILL PROTECT BY ITS MINIATURE ALARM.
i) REGISTERS:
RESISTORS ARE THE ELECTRONIC COMPONENTS WHICH OPPOSES CURRENT.
RESISTORS OBEY OHMâ„¢S LAW.
DIFFERENT KIND OF RESULT COMES WITH RESPECT TO APPLICATION OF VARIOUS VOLTAGES.
ii) CAPACITORS:
A CAPACITOR IS AN ELECTRICAL OR ELECTRONICS DEVICE THAT CAN STORE ENERGY THE ELECTRIC FIELD BETWEEN A PAIR OF CONDUCTORS.
THE PROCESS OF STORING ENERGY IS CALLED ËœCHARGINGâ„¢.
A 47microF 25V CAPACITOR IS USED.
iii) INTEGRATED CIRCUITS:
IT CONSISTS OF
MINIATURIZED
ELECTRONIC
COMPONENTS BUILT INTO
AN ELECTRICAL NETWORK.
HERE TWO ANALOG
DESIGNED IC ARE USED.
- IC TLO71(IC1):IC1 IS USED AS
VOLTAGE COMAPARATOR.
- IC CD4538(IC2):IC2 IS USED AS A
MONOSTABLE WITH TIMING
ELEMENTS R5 AND C1.
iv) DIODE:
IN DIODES CURRENT IS DIRECTLY RELATED TO VOLTAGE.
DIODES ARE NON-LINEAR,TWO TERMINAL,
PASSIVE ELECTRICAL DEVICES.
A 1 JUNCTION DIODE (1N4148) IS USED IN THIS CIRCUIT.
v) BATTERY:
A 9V BATTERY IS USED
vi) TRANSISTOR:
TRANSISTOR AMPLIFY CURRENT AND VOLTAGE.
IT MAY BE USED AS SWITCH.
A pnp TRANSISTOR BC558(T1) IS USED IN THIS CIRCUIT.
vii) SWITCHES:
a) TILT SWITCH:
A TILT SWITCH IS
MADE UP OF PLASTIC BOTTLE
WITH TWO STAINLESS PINS AS
CONTACT OR PROBES.
IN TILT SWITCH 2/3RD OF THE
BOTTLE IS FILLED WITH WATER
SUCH THAT THE WATER CANNOT
MAKE CONTACT WITH THE PINS.
b) ON/OFF SWITCH:
A ON/OFF SWITCH OF 3A IS
USED.
THE USER CAN USE THE SWITCH
AS PER HIS REQUIREMENTS.
viii) PIEZO BUZZER:
A PIEZO-BUZZER IS USED AS AN ALARM.
USERS CAN USE ANY BUZZER AS PER THEIR CONVINIENCE.
ix) PRINTED CIRCUIT BOARD:
ALL THE ABOVE EQUIPMENTS ARE MOUNTED ON THE GENERAL
PURPOSE PCB.
THE UNIT IS INSIDE THE LAPTOP CASE IN HORIZONTAL
POSITION. IN THIS POSITION, WATER INSIDE THE TILT
SWITCH EFFECTIVELY SHORTS THE CONTACTS, SO THE
OUTPUT OF IC1 REMAINS LOW . THE ALARM GENERATOR
REMAINS SILENT IN THE STAND BY MODE AS TIGGER PIN 5 OF IC2 IS
LOW.
WHEN SOMEONE TRIES TO TAKE THE LAPTOP CASE, THE UNIT TAKES THE
VERTICAL POSITION & THE TILT SWITCH BREAKS THE ELECTRICAL CONTACT
BETWEEN THE PROBES. IMMEDIATELY THE OUTPUT OF IC1 BECOMES HIGH
& MONOSTABLE IC2 IS TRIGGERED. THE LOW OUTPUT OF IC2 TRIGGERS THE
pnp TRANSISTOR(T1) & THE BUZZER STARTS BEEPING.
1. CHEAPNESS: It is affordable for general use.
2. CLEANLINESS: It is clean as it doesnâ„¢t produce fume or poisonous gas.
3. AVAILABILITY: All equipments used in this circuit are easily available in the market.
4. EASY CONSTRUCTION: It is easy to construct for a person who has general idea about circuitry elements.
5. THERE SHOULD BE NO LEAKAGE IN TILT SWITCH.
6. BEFORE LEAVING THE LAPTOP THE USER SHOULD CONSIOUSLY ON THE SWITCH.
THE LAPTOP PERFORMS DIFFERENT
TASK IN DAY-TO-DAY LIFE. SO,IT SHOULD BE PROTECTED.
KEEP THE LAPTOP CASE IN HORIZONTAL POSITION & SWITCH ON
THE UNIT.LAPTOP IS NOW PROTECTED.
