DESIGN AND CONSTRUCTION OF ANTI-THEFT ALARM FOR VEHICLES
DESIGN AND CONSTRUCTION OF ANTI-THEFT ALARM FOR VEHICLES
1 Background of the study
The rate of increase in car theft in this part of the world has reached an alarming rate. In the rave of this development, engineers in this country have been performing researches aimed at providing a lasting solution to this endemic act  . This research team in an attempt to proffer a lasting solution thought of exploring the electronic car anti-theft device techniques as possible remedy. The implementation is divided into twosubsystems: the alarm and the vehicle anti theft subsystems. The importance of this design cannot be over emphasized since it helps to reduce the rate of vehicle theft within our society. For instance, when there is an intruder into the vehicle, the system will immediately and automatically demobilized the car after few seconds the intruder moves the car thereby blowing an alarm the status of the car and preventing the car from being stolen. This automobile security system is manually operated. Few of the many auto-motive theft-prevention systems allow a vehicle to start and temporarily run before disabling a critical component, such as the fuel or ignition system. In case of hijacking, the driver can leave the car safely, and then use any phone to send out some commands and remotely cut off power or gasoline supply, so as to stop the car from running and get back the car easily. In such case, the vehicle snatcher will not be in a position to harm the vehicle owner. Car security system has been very popular in recent times and widely used in most cars and automobiles owned by companies, business organizations and even by some private individuals who can afford the cost.
1.2 Statement of the problem
This design is a theft deterrent system that simulates problems in motor vehicles. On engine startup, this system allows normal engine operation for a random time duration during which it can be deactivated. The device is not an alarm system, but can function well in conjunction with any alarm device. Whenever an unauthorized use is detected, a digital controller randomly generates a unique controlling signal with random timing variations that is communicated to the remote receiving subsystem interface units. These units can be connected in series with vital vehicle sub-system components in order to interfere with typical subsystem component operation, thereby inducing the illusion of an actual vehicle problem severe enough to inhibit vehicle drivability. This system allows unique implementation by locating disabling receivers on any variety of vital vehicle subsystems, presenting thieves with multiple unknowns specific to each vehicle. Hence, there is no chance for a pattern to be developed and very little possibility that the device will be recognized by an unauthorized operator  .
This system consists of several components coupled with motor vehicle subsystems. The heart of the system is the modem module which integrates the capability of a microcontroller. This module supervises the entire system, communicating with one or more re-mote disabling receivers (mobile phone), which act as the interface circuitry between the controller and the motor vehicle subsystem. The onboard controller performs the generation of random control information signals. A variety of methods can be used to generate the random control information signals, including receiving a radio frequency, using digital logic components, or programming a micro-controller, in order to provide a random control information signal  . The functionality of the system is based on the ignition key switch and anti-hijacking output, in addition to an input circuit. The key switch input simply connects the battery to the coil ignition system of the vehicle.
1.3 Aim and objective
The main aim and objective of the design and construction this project is to create a comfort in the minds of vehicle owners or users when their vehicles are parked or stationed anywhere without much fear of car-theft. This project is aimed at constructing a car anti theft alarm which will deactivate the ignition if the right code is not entered (or is not entered correctly) or the switch is not pressed, and the switch or code must be hidden which must be known only by the right user.
1.4 Significance of the project
This device functions as an electronics watch dog. This device functions as a major security alarms used in an cars which can also be used in residential, commercial, industrial, and military properties for protection against burglary (theft) or property damage, as well as personal protection against intruders.
This system doesn’t require the car owner to activate it; it operates automatically. Alarm is considered as providing much more effective anti-theft protection than an audible alarm alone; many auto insurance companies offer lower rates for vehicles that are equipped with them.
To determine whether there is a device in the car, it is very difficult. If the alarm is intended to scare off intruders this creates many problems. To theft a thief can thoroughly inspect the car, but the protective device will not notice, and after the break he was waiting for trouble.
The alarm is almost impossible to disconnect: to determine the location of the system unit from the first impossible, and the principle of operation of many of the hijackers are unknown. The simplicity and ease of use. High reliability and silent operation, which is important.
1.5 Scope of the project
A car an anti-theft alarm mechanism prevents an automobile’s engine from starting unless the correct ignition key is inserted into the ignition slot. One of the advantages is that the car owner does not have to remember to activate it – its operation is automatic. The device is considered as a passive anti-theft system since it does not require action from a person to make it work. One disadvantage of the system is that car keys with the embedded transponder are more expensive and time consuming to replace if lost and usually requires a visit to a car dealer. Most new vehicles have some anti theft security as standard equipment, but aftermarket or add-on is available for older cars or vehicles without factory-installed.
Anti theft alarm is an electronic device that arms automatically when your vehicle is switched off and prevents unauthorized starting of the vehicle.
Anti theft alarms are integrated into the vehicle’s circuitry and engine-management system. They automatically interrupt the power to multiple electronic circuits, usually the starter motor, ignition and fuel pump circuits, when the specially coded key is removed from the ignition switch, or the vehicle is shut off.
Only if the correctly coded key (or other coded element) is used and recognized by the system will the circuits be enabled, allowing the car to start. Anti theft alarms typically have a transponder or resistor embedded in the head to communicate the code to the engine-management system.
If the correct code is not recognized, or someone attempts to start the vehicle by some other means – such as hotwiring or breaking the ignition lock cylinder – the system will remain armed and prevent the car from starting. An anti theft alarm should always be at the core of any car theft deterrent system. It is the most effective means of preventing drive-away theft.
1.6 Limitation of the project
- For the device to work, the owner must put ON the ignition
- Car keys with the embedded transponder are more expensive and time consuming to replace if lost and usually requires a visit to a car dealer.
- The system can cause accident if not de-activated in time.