The design and study of a computer- controlled security system(CCSS) based on a GSM phone
Computers are finding important use in home automation, communication technology, security systems, etc. Communication between a computer, sensors, and a mobile phone can be achieved by use of appropriate interfacing techniques and a suitable program. A mobile phone has found use in the areas of security, voice-to-voice communication, sending and receiving short text messages and access information services available with the network carriers. This research project focused on designing a security system that alerts a mobile phone user of a possible intrusion into his or her house, business premises, car, etc. A passive infrared (PIR), magnetic contact sensors, an alarm and a mobile phone were interfaced to a computer. The PIR sensor senses heat from a body, and the magnetic contacts sense the opening of a door or window. In this study, a Computer-based prototype system appropriate for accepting signals from sensors and controlling an alarm and a mobile phone is presented. Personal Computer (PC) parallel and serial/USB ports were configured, programmed, and used in accepting signals and controlling a mobile phone and an alarm. Once the personal computer (PC) receives input signals from the sensors, it commands the interfaced mobile phone to send a predetermined text message using the short message services (SMS) of a mobile phone network. The SMS is sent to a designated person. After a short delay, the computer triggers an alarm system. The use of a PC as a control element provides a secure security system which does not require monitoring by a central station of a private firm. The various components used in constructing the system hardware were chosen based on their performance and suitability for use in a security system. One unique part of the system was its power supply; it was able to supply IOV and 5V. Software for control, scanning of input and interpretation, was developed using C++ programming language. The operational system was tested for its suitability and reliability as a security system. Tests showed that the magnetic sensor pulled in at a distance of about 2.3cm when fixed on steel, while on air it pulled in at a distance of about 4.3cm. The PIR sensor was found to have a horizontal range of about l Om.The security system was found to be reasonably fast in sending a SMS; on average it took 25s. The mobile phone network showed a very high degree of success in sending a SMS. The alarm went off every time after sending a SMS. After suitable modifications this system can be installed in homes, banks, institutions, vehicles, factories and any other area requiring this kind of security system (with the necessary modifications).