AUTOMATIC THEFT CONTROLLER

SYSTEM USING BURGLAR ALRAM

Innovations in the Burglar alarm

INTRODUCTION:

Burglar alarm is the one of the security system which is use to prevent our home, office, banks, etc. In our project burglar alarm is mainly used to find out the theft and it can also give the signal to the user or owner by using of the mobile phones. So the theft can be avoided and the thief also will be caught.

The concept of burglar alarms was introduced to the world by Edwin Holmes. Holmes made these alarms an important component of business and residential security. In 1905, after enjoying several years of successful business, Holmes sold the concept of burglar alarms and his company to American Telephone and Telegraph Company (AT&T). AT&T then went a step further and connected burglar alarms to emergency call systems at both fire and police departments.

CONCEPT OF BURGLAR

ALARMS

. Burglar alarms are systems designed to detect

unauthorized entry into a building or area.

They consist of an array of sensors, a control panel

and alerting system, and interconnections

Sensors detect intruders by many methods such as

monitoring door and window contacts by passive infrared motion detectors ultrasound vibration electric or magnetic fields microwaves

Sensors may be directly wired to a control panel that

provides sensor power, or may communicate wirelessly.

LET’S GET THE BASIC STRAIGHT.

(BEFORE “THEY “ DO)

STEPS INVOLVED:

These things take place in a sequence:

Step 1: Try and catch the burglar at the door step it self,

In a burglar alarm, the switch detects the act of intrusion in any circuit, to turn the electricity on or off; you open or close part of the circuit using a switch.

BREAKING THE CIRCUIT:

1.closed-circuit system(if somebody opens the door, the circuit is opened, and electricity can't flow. This triggers an alarm) 2.open-circuit system (opening the door closes the circuit, so electricity begins to flow and the alarm is triggered)

These sorts of alarms are divided into two categories:

Closed circuits are normally a better choice than open circuits because an intruder can deactivate the open circuit by simply cutting the connected wires.

A BASIC MAGNETIC SENSOR :

A MAGNETIC SENSOR IN A CLOSED CIRCUIT CONSISTS OF A FEW SIMPLE COMPONENTS. FOR THE MOST BASIC DESIGN, YOU NEED:

(1) A BATTERY POWERING A CIRCUIT

(2) A SPRING-DRIVEN METAL SWITCH BUILT INTO A DOOR FRAME

(3) A MAGNET EMBEDDED IN THE DOOR, LINED UP WITH THE SWITCH

(4) A SEPARATELY-POWERED BUZZER WITH A RELAY-DRIVEN SWITCH.

WHAT IS CONTROL BOX?WHY IT IS NEEDED?

o The burglar only needs to close the door again to turn the buzzer off. That's why

most modern burglar alarms incorporate another piece into the circuit -- the control box.

oThe control box is hooked up to one or more alarm circuits, but it also has its own power supply.

oBut once the alarm is triggered, the control box won't cut it off until somebody enters a security code at a connected keypad.

oIt monitors the circuits and sounds the alarm when they are closed or opened (depending on the design).

oFor added security, the control box is usually positioned in an out-of-the-way spot, so the intruder can't find it and attempt to destroy it..

Step2: burglar managed to escape the circuits……now what..?

DETECTION OF MOTION:

The intruder's actions are highly unpredictable once he is inside -- you don't know where they'll go or what they'll touch. A specific "trigger" isn't very effective. To detect an intruder who's already in the house, you need a motion detector.

An automatic door opener is an example of a radar-based motion detector.The motion detector emits radio energy into a room and monitors the reflection pattern.

Another simple design is photo-sensor motion detectors. Photo- sensors have two components

(1) A SOURCE OF FOCUSED LIGHT (OFTEN A LASER BEAM) (2) A LIGHT SENSOR

Passive infrared (PIR) motion detectors: »In a home security system, you aim the beam at the light sensor, across a passageway in your house.

»When somebody walks between the light source and the sensor, the path of the beam is blocked briefly.

»The sensor registers a drop in light levels and sends a signal to the control box.

The motion detector emits radio energy into a room

and monitors the reflection pattern.

More advanced security systems include passive infrared (PIR) motion detectors.

These sensors "see" the infrared energy emitted by an intruder's body heat.

When an intruder walks into the field of view of the detector, the sensor detects a sharp increase in infrared energy.

Of course, there will always be gradual fluctuation of heat energy in an area, so PIR detectors are designed to trigger the alarm only when infrared energy levels change very rapidly.

All these motion detector designs can be combined in a house to offer complete coverage.

In a typical security system, the control box will not sound the alarm immediately when the motion detectors are triggered.

There is a short delay to give the homeowner time to enter a security code that turns the system off.

The "motion sensing" feature on most lights (and security systems) is a passive system that detects infrared energy.

PHOTO-SENSOR MOTION DETECTORS

These sensors are therefore known as PIR (passive infrared) detectors or pyroelectric sensors.

In order to make a sensor that can detect a human being, you need to make the sensor sensitive to the temperature of a human body. Humans, having a skin temperature of about 93 degrees F, radiate infrared energy with a wavelength between 9 and 10 micrometers. Therefore, the sensors are typically sensitive in the range of 8 to 12 micrometers.

If somebody disturbs the reflection pattern, the motion detector sends an alarm signal to the control box.

Time Delay: IN A TYPICAL SECURITY SYSTEM, THE CONTROL BOX WILL NOT SOUND THE ALARM IMMEDIATELY WHEN THE MOTION DETECTORS ARE TRIGGER.

ALL THESE MOTION DETECTOR DESIGNS CAN BE COMBINED IN A PHOTO-SENSOR MOTION HOUSE TO OFFER COMPLETE DETECTORS COVERAGE.

PIR DETECTORS ARE DESIGNED TO TRIGGER THE ALARM WHEN INFRARED ENERGY LEVELS CHANGE VERY RAPIDLY.

WHEN SOMEBODY WALKS BETWEEN THE LIGHT SOURCE AND THE SENSOR, THE PATH OF THE BEAM IS BLOCKED BRIEFLY. IN A HOME SECURITY SYSTEM, YOU AIM THE BEAM AT THE LIGHT SENSOR, ACROSS A PASSAGEWAY IN YOUR HOUSE.

THE SENSOR REGISTERS A DROP IN LIGHT LEVELS AND SENDS A SIGNAL TO THE CONTROL BOX.

Step3: Sounding the alarm

(1)A SIREN OR OTHER LOUD ALARM NOISE (2)FLASHING OUTDOOR LIGHTS (3)A TELEPHONE AUTO-DIALER

In an advanced system, the control box will be wired to several different components. . Typically, it will activate:

The siren and lights serve three functions:They signal to police which house has been broken into. They drive the intruder away. They alert occupants and neighbors that someone has broken into the house.

The telephone auto-dialer can: Dial the police directly, and play a pre-recorded message giving the address of the house and any other relevant information

A BASIC CIRCUITRY:

I n this basic circuit, the alarm will be switched on under the following four different conditions: 1. When light falls on LDR1 (at the entry to the premises). 2. When light falling on LDR2 is obstructed. 3. When door switches are opened or a wire is broken. 4. When a handle is touched.

DEFECTS AND REMEDIES SUJESTED:

IF POTENTIOMETER VR3 TAPPING IS HELD MORE TOWARDS GROUND, THE ALARM WILL GET SWITCHED ON EVEN WITHOUT TOUCHING.

In such a situation, the tapping should be raised. But the tapping point should not be raised too much as the touch action would then vanish.

BATTERY BACKUP IS NECESSARY FOR THIS CIRCUIT

RELAY COILS PRODUCE LARGE REVERSE VOLTAGE SPIKES

short circuits these spikes before they can do any damage. >To avoid this adjust potentiometer VR3 properly.

short circuits these spikes before they can do any damage.

ELECTRIC SPARKING IN THE VICINITY OF THIS CIRCUIT MAY CAUSE FALSE TRIGGERING OF THE CIRCUIT

AN IMPROVED FORM OF BURGLAR ALARM

(WITH CHANGES AND INCREASED EFFICIENCY)

The Automatic Intruder Alarm uses a Cmos 4011.The 4011 has four two-input NAND gates.NAND gates only produce a low o/p if both i/p are high. The errors of the previous model have been considered and rectified along with further improvements.

PART LIST1X CMOS 40111X BC547 1X ENTRY BUZZER 1X RELAY 1X SIREN MISC: DIODES, RESISTORS, CAPACITORS, TRANSISTORS, SWITCHES, ETC...

Exit delay:

It gives the owner time to exit the area without triggering the circuit.

# during this time the alarm cannot be activated.

# So it's safe to open the loop and exit the building.

# Once C2 has charged, the Exit Delay is finished

and pin 6 is high. Now if any one enters the area(even if it is the owner himself ) it will trigger the circuit

But the user can use entry delay to stop the triggering of the alarm

Detect and Rectification: THE WIRES GOING TO THE SWITCHES ON THE

DOORS, WINDOWS, ETC. CAN ACT LIKE A RADIO ANTENNA.

THEY PICK UP STRAY SIGNALS THAT CAN CAUSE 'FALSE ALARMS‘.

C1 IS THERE TO DE-TUNE THE WIRES - AND SHORT-CIRCUIT ANY HIGH FREQUENCY SIGNALS TO GROUND.

C4 DOES A SIMILAR JOB FOR THE SUPPLY. THE ERRORS ARE TO BE RECTIFIED CAREFULLY.

Conclusion:Home security is a rapidly growing field, and there are new and improved burglar alarms popping up all the time.

With rapid advancement of technology the field is turning out to be an area full of scope

Even these circuits may develop faults as time goes and new changes can be made to make them more efficient.

Home security is a field that can never be ignored by the engineers as it does have scope for years to come, because security is of prime importance to one and all.