INTRODUCTION
This work is on design and construction of a SMS based home security system. Security is the main concern for everyone. Everyone wants to live securely in his/her house. Everybody wants themselves to keep safe or secure from various incidents like theft in their house or accidents caused due to LPG gas leakage or accidents due to fire in their house. Now days many times we hear news about house robbery or theft in some houses, bungalows, flats. These robberies or thefts take place when nobody is in house or in some cases we find that robbery take place even if people are in their houses. Another bad news we hear is about accidents are caused or blast happens because of LPG gas cylinder leakage. In house we find that LPG gas is commonly and widely used for cooking purpose. So in every kitchen we find that LPG gas cylinder is placed. However due to some reasons, LPG gas might leak from these cylinders. And because of this LPG gas leakage, fire might be ignited or it can even cause the LPG gas cylinder blast. Which can damage the house or in even worst situations, it can cause life threat to the person living inside the house.
This project has 3 basic modules along with a GSM modem. GSM modem is used to send the SMS whenever there are changes in any of the three modules.
First module of this project detects if any person is entering inside the house. This feature is helpful at night time or whenever we are out of our home.
Second part of project serves the functionality of a door-latch opening using a password entered through keypad. As well as sending this data to a GSM modem through serial port. This module also turns on buzzer if 3 wrong passwords are entered consequently. User can change this password anytime he/she wish using a keypad.
Third module uses LPG gas sensor to detect the gas leakage. If there is leakage then buzzer is turned on.
Another problem / fear are about fire in our house. There can be various reason of this fire being ignited or house getting caught in fire. Reason of fire can be electrical short circuit or due to some other things like candles or oil lamps kept inside our house or because of fireworks in festival season. Early detection of all these problems is really necessary. Sometimes fire lighted is small but if proper attention is not paid to it or if proper actions are not taken to control this fire, then it can convert into big tragedy as this fire can spread in complete house. Same with LPG gas leakage, if it is detected on time and if it is controlled on time then it can avoid a big accident. Also in case of robbery it would be beneficial if we can blow some alarm. Let’s take an example that we are out of our home and theft is going on in our house. In such case if we are intimated about theft then we can inform our neighbors, then they can create some noise or take some appropriate action so that this theft can be avoided. Let’s take another problem; sometimes key of our home is lost. If we do not replace our lock and if these keys are found by thieves then it can cause robbery. We all know that duplicate key can be created within few minutes and also key duplication is easy. These are the disadvantages of traditional locking system which uses a key and a lock. To overcome all the above stated disadvantages of existing system we have designed a GSM based home security system. It can avoid these undesirable situations, hazardous conditions like LPG gas leakage, fire ignition and theft.

1.2 AIM OF THE PROJECT
In this project, the main of this work is to designed a simple but very efficient home security that has a function of sending sms to the homeowner on his/her mobile number in case of an intruder, fire or wrong entry alert which also trigger a cctv which captures the activity of the intruder.

1.3 SCOPE OF THE PROJECT
This project has 3 basic modules along with a GSM modem. GSM modem is used to send the SMS whenever there are changes in any of the three modules.
First module of this project detects if any person is entering inside the house. This feature is helpful at night time or whenever we are out of our home.
Second part of project serves the functionality of a door-latch opening using a password entered through keypad. As well as sending this data to a GSM modem through serial port. This module also turns on buzzer if 3 wrong passwords are entered consequently. User can change this password anytime he/she wish using a keypad.
Third module uses LPG gas sensor to detect the gas leakage. If there is leakage then buzzer is turned on.

1.4 SIGNIFICANCE OF THE PROJECT
i. Constant Protection: If you install a monitored alarm system in your home, you and your family have round-the-clock the protection against break-ins. Some systems also have fire alarms built in, which provides additional reassurance. The constant protection of an alarm system is particularly comforting when you may be away from your home for an extended period or you must leave your children home alone for an evening. It also means that your home is protected while you are sleeping so you can have peace of mind about your family’s safety and get a good night’s sleep.
ii. Deterrent to Criminals: Most home alarm systems provide small lawn signs or placards for your window that indicate that your home is protected by a security company. In many cases, the presence of this type of sign alone may persuade burglars and other criminals to pass over your home and move on to a dwelling that is not protected by a security system. Be sure to clearly display the decals and signs from your monitoring company to fully advertise your home’s security.
iii. Lower Insurance Rates: While there is a significant cost to install a home alarm system, it can mean a financial advantage as well. Your insurance company may actually adjust the rate on your homeowners insurance policy if you have a system installed in your home. Because your home is protected from theft – and in many cases, fire – costly incidences that might require you to make a claim are less likely to occur in your home. As a result, your insurance company can lower your rate.
iv. Remote indication: With the use of GSM technology owner of the house or industry get remote indication through SMS. So even if the user is away from home or industry, he/she will be intimated about the hazardous or undesirable conditions / situations inside the house.
v. This system is fully automated. So once this system is installed inside home or industry, then it does not require any human interaction to operate.
With the use of this system we can save the life of person inside home / industry. Since the accidents caused due to fire and LPG gas leakage can cause life threat.
vi. Also the property inside house and various materials inside the house and industry are saved from to theft and from fire detection.
vii. This system is Cost effective. Also it is Fast and efficient

1.5 PROBLEM OF THE PROJECT
Cut Phone Line: If your alarm system is connected to your security company by phone line only, you can run into problems. A burglar may cut your phone line before entering your home and all monitoring and communication with your alarm company is terminated. As a result, it is a good idea to have a cellular radio installed with your system, which will allow communication with the security company even if the phone line is cut.
False Alarms: While a home alarm system can provide security and peace of mind, it has the potential to become fairly annoying as well. It is not uncommon for false alarms to occur with your system. In some cases, the police or fire department may be dispatched to your home before you have a chance to explain the mistake to your security company. Some police departments may charge you if they are repeatedly called to your home without reason. To avoid false alarms, consult with your alarm company to determine what might be causing them so you can make adjustments.
Expense: The primary disadvantage of a home alarm system may be its expense. It is costly to have the system installed in the first place, but security companies charge a daily or monthly fee to provide monitoring services as well. These fees can quickly add up, so if you are on a budget, it may put a strain on your finances.
1.6 APPLICATIONS OF THE PROJECT
1) This project has its main application in security system. This project can be used in home as SMS based domestic security system. It will be really useful for the security of flat, bungalow or any row house. It can be used in our house for theft detection at night time. The other part of the project (password detector) can be used to automate the door locking process, so the user need not to carry the door lock keys along with him, he/she can just remember the password and use it later to open the door.
2) Various parameters monitored in this project like LPG gas leakage, theft detection and overheat due to fire are also applicable for industrial purpose as well. So this system can also be used in industries as a GSM based industrial security system.
3) We can use this project in Restaurants as well as hotels, since LPG Gas cylinders are majorly used for cooking purpose in hotels and restaurants. Also they are very much prone to fire. So this project can be fitted in cooking section or kitchen of hotels. We can also use this project for the lodging rooms in hotels or rented rooms in a hotel. User will be provided a password to enter in this room and various parameters in this room will be monitored.
4) This project can be used in hospitals. We need to do little bit modifications for use in hospital. We can add oxygen gas sensor to detect the leakage in oxygen gas cylinders, as it can also cause fire. The password operated locking section can be used in hospitals for those rooms which have limited access like rooms with chemical or x-ray machine units. So only authorized person can gain access to this areas/rooms/sections.