Abstract: Nowadays security is a vital issue in our day to day life. In the present world, crime becomes increasing and people want to secure their asset at their house. In this situation, an owner wants an advance technology so that he doesn’t worry about the assets when he doesn’t present in his house. This paper discusses about a simple but very effective technique that can be applied into home security. SMS based security box reduce the rate of the crime and secure our assets. The box is designed in such a way that when someone except the owner opens the box it will send an SMS (Short Messaging System) to the owner mobile using the GSM (Global System for Mobile) module. Main motive about this paper is to make a low-cost security box but its benefit will be high.Introduction:In the modern age of digital technology, the security system is one of the important topics. First, what do we understand the word ‘security system’? Security means the degree of defense against damages, risk, loss and crime 1. It is a form of protection structures and processes. A security system provides us a form of protection that ensures the safety and security of the assets when you are at the home or out of the home.Most of the security systems available in current, needed wiring, expensive, complex mechanism, bulky sized and many other problems 2. Hence, an easy and comprehensive portable and simple security system should be developed to fill up those loophole gaps. The implementation of this paper is to provide the user a security box which is cheap in price, low weight. The system alerts the user through SMS instantly when someone opens the box before the given time.The main focuses of this security system are to providing security when the user is away from home or his working places. In GSM mobile technology SMS (Short Messaging Service) is a technique that can perform anywhere whenever it needed 3. As the message can send quickly, accurately and at a low cost, so here chose the GSM module. Reasons for choosing GSM module are, GSM technology takes input signal from machinery to output message on device 5. That means that after detection of any intrusion GSM module will active. In the system, SMS facility will be very effective, where information or alert message sent by the GSM module and those information or alert message received by the user. The home security system is different types of sensor-related home security, keypad based security, Figure print, Palmprint and so much 4. But after so many research I chose GSM based home security because it is better than the other all as it is easy to install and having a very low cost. Besides wireless technology is used and very popular to control home security systems instead of wired topological connection and nowadays almost all the people using mobile phone so using this system user will not have to carry or buy any additional device to monitor their house.When the owner of the box away from the home or industry, all the sensors are activated by switching on the Security system. Whenever an intruder tries to open the box before the time owner set then the LDR (Light Dependent Resistor) sensor will activate and make an alert sound using the buzzer and at the meantime send an SMS to the owner of that box using the GSM module. Seeing the SMS, the owner understand that someone tries to open her box. On the other hand, after the fixed time (user set the time before closing the box) the box will automatically open. Here, Arduino Uno controls all the system. The concept is easy and the security system is new, unique and more reliable than other automatic security systems. Also, this system is portable, easy to install, reasonable price and can be used in any environment.Conclusion:In the present situation, people getting more concerned to secure their house from unauthorized people. SMS based security system implemented in an easy method and is very easy to use in homes, offices and so on. It is possible to develop and implement the system in a limited budget, low power conception, compact in size and user-friendly. As the user can monitor premises from anywhere in real time it increases the safety of the private premises. As long as the mobile communication network is present user get an alert message through the GSM technology. Methodology:According to the hardware design, the system and functional block diagram are shown in Figure 1 and Figure 2. System block diagram showing how all the components are interrelated to each other and the functional block diagram show the components work. Flowchart of the Total System:The flow chart of the total system is shown in Figure 3. Here we clearly show how the total system will run and the process of the security in step by step.