Abstract: The main objective of this project is to provide security to places such as banks, museums, shops etc. during non working hours. Security of valuables at such places can be assured by installing this system during non business hours especially night hours when there is none to safeguard the property. This system senses the presence of a person who tends to loot and immediately activates the system which provokes the security station or a police station by initially transmitting an alarm tone and then immediately transmitting pre-recorded information stating where the theft has broken down. The control of this mechanism is provided by a microcontroller and transmission is done using FM techniques. Infrared sensors are used to detect the presence of a person who breaks the place during non working hours. For this purpose two sensors are used, namely signal generator and signal receiver. From the signal generator infrared rays are emitted through the infrared LED and these rays are detected by the receiver infrared LED. These two infrared LEDís are arranged parallel to each other at the entrance. The distance between these two sensors can be increased to the required length, by increasing signal delivering power of the transmitter depending up on the area of the Room. The output of the signal receiver circuit is fed to microcontroller, such that whenever any person passes between the sensors, the controller gets high signal. On receipt of a high signal from the infrared sensor, the microcontroller energizes the relays, and the program is prepared such that one of the relays will be active for 20 seconds (relay-1) and the other for 70 seconds. The relay-1 contact is used to energize the alarm while the relay-2 contact is used to energize the cassette player mechanism, and the recorded information produced by the tape head amplifier is super imposed over the carrier and transmitted as a modulated wave using F.M transmitter. In the audiocassette, address of the system is recorded. In this project, condenser MIC amplifier is also used, and this is very sensitive MIC amplifier, which picks-up very low sounds also perfectly. The idea of using this MIC amplifier is, to transmit the voice or conversion of the intruders through the F.M. transmitter. The output of MIC amplifier, Tape head amplifier and 1 kHz signal generator is connected to the input of carrier generator. Two digits digital display system is designed with 7-segment displays and it is connected at the output of the microcontroller, therefore whenever the controller receives interrupted signal, the display shows 90 and starts counting in decrementing mode, finally when display shows zeros, controller de-energizes both the relays automatically. The receiving Module of the project work is, supposed to be installed at police station or security office, where the system alerts the police officials or security guards for taking the necessary action immediately. In the receiver the received signal is amplified using an Audio amplifier and the amplified signal is fed to the loud speaker.
Keywords: LED, MIC, IR, IC, RAM, DST, DPTR, NEMA, PCB, CCTV