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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 LED’s 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.
INTRODUCTION
Now-a-days a lot of importance is growing for the security aspects as the crime rate is increasing. This project report describes about the design and development of ‘Modern Security System with recorded Message transmitter’ which can be used in Banks, industries, jewellery shops, Temples, Go-downs, Museum’s and other places where the valuable material is stored. This kind of security system can be used for home security also.
This type of security systems is quite suitable for the isolated colonies or remote houses. A house, which is far away from the town or city, must be equipped with this system. This system will guard the house when residents are out and automatically transmits the theft information to the nearest police station or security office where the receiver is installed.
In order to check the un-authorized entry of persons into important places, many electronic security systems are developed and have become one of the important fields in the electronics. Many types of electronic systems are available in the market, such as, digital code locking system, Metal detectors, intruder alarms, touch detectors, fire alarms, closed circuit television systems, coded cards and magnetic cards for identifying the persons, scanners, burglar alarms, sound operated light switches, etc; These type of security systems are readily available in the Market, but the one which is mentioned in this report is designed using latest techniques and is not available in the Market.
In this project work, the control circuit is designed with microcontroller and the program is prepared such that, whenever the controller receives interrupted signal from the IR sensors, the controller energizes the relay and remains active for a specific time. The relays get deactivated once the display shows 00. The time for relay to remain in active state can be programmed according to the requirement. The idea of providing time delay is, during this time, the recoded information can be transmitted to the nearest Police station. In this project work cassette player mechanism is used, and supply is provided to the player through the relay contact. The pre-recorded message that contains the address of the system is super imposed over the carrier and transmitted as a modulated wave.
In this project work, microcontroller chip is playing a major role, the controller used in this project is ATMEL 89C51, and this is 40pin IC having 32 I/O lines. Nowadays with the advancement of technology in the field of micro-controllers, all the activities in our day-to-day living have become part of information technology and we find micro-controllers in each and every application. Thus, the trend is directing towards controller based project works. However in this project work, the basic signal processing of information gathering from the sensors is done with analog circuit, for this purpose IR sensors are used. These sensors can be called as optical sensors, the detailed descriptions of these sensors and microcontroller are provided in the subsequent chapters.
2.0 DESCRIPTION OF BLOCK DIAGRAM
Fig 2.1 Block diagram of modern security system with message transmitter
The complete block diagram of the project is as shown above. The description of various blocks is given as below:
2.1 IR SIGNAL GENERATOR AND RECEIVER
The principle of remote sensing is utilized in this project work, to detect the presence of any person wherein the IR transmitter and receiver blocks are installed. There are many occasions, when the presence of a person / object in the given area can be detected without making any contact with them.
The IR transmitting LED as well as receiving LED is arranged parallel to each other at the entrance of main door, where the presence of the person is to be detected. The range between the transmitting LED and receiving LED is restricted for less than 1 foot, because since it is a prototype module, the output of the timer IC is not amplified. This range can be increased by increasing the radiating power of the transmitting LED, by adding a suitable amplifier. The receiving LED receives continuous signal from the transmitting LED, whenever any person passes between these two sensors, the signal is interrupted, by which the controller receives high signal from the signal receiver block.
2.2 MICROCONTROLLER AND DISPLAY
On receipt of interrupted signal from the receiver block, the controller energizes the relay and the program is prepared such that, once the relay energized it remains active for 90 seconds. When the relay gets energized, the controller also drives the display simultaneously and the display shows 90 initially and starts decrementing immediately. Finally when display shows all zeros, the relay deactivates automatically. The display section is designed with two 7-segment common anode displays and it counts seconds in decrement mode.
Micro-controller unit is constructed with ATMEL 89C51 Micro-controller chip. The ATMEL AT89C51 is a low power, higher performance CMOS 8-bit microcomputer with 4K bytes of flash programmable and erasable read only memory (PEROM). Its high-density non-volatile memory compatible with standard MCS-51 instruction set makes it a powerful controller that provides highly flexible and cost effective solution to control applications.
Micro-controller works according to the program written in it. Most microcontrollers today are based on the Harvard architecture, which clearly defined the four basic components required for an embedded system. These include a CPU core, memory for the program (ROM or Flash memory), memory for data (RAM), one or more timers (customizable ones and watchdog timers), as well as I/O lines to communicate with external peripherals and complementary resources — all this in a single integrated circuit. A microcontroller differs from a general-purpose CPU chip in that the former generally is quite easy to make into a working computer, with a minimum of external support chips.
A traditional microprocessor won't allow you to do this. It requires all of these tasks to be handled by other chips. For example, some number of RAM memory chips must be added. The amount of memory provided is more flexible in the traditional approach, but at least a few external memory chips must be provided, and additionally requires that many connections must be made to pass the data back and forth to them.
For instance, a typical microcontroller will have a built in clock generator and a small amount of RAM and ROM (or EPROM or EEPROM), meaning that to make it work, all that is needed is some control software and a timing crystal (though some even have internal RC clocks). Microcontrollers will also usually have a variety of input/output devices, such as analog-to-digital converters, timers, UARTs or specialized serial communications interfaces like I²C, Serial Peripheral Interface and Controller Area Network. Often these integrated devices can be controlled by specialized processor instructions.
Originally, microcontrollers were only programmed in assembly language, or later in C code. Recent microcontrollers integrated with on-chip debug circuit accessed by In-circuit emulator via JTAG (Joint Text Action Group) enables a programmer to debug the software of an embedded system with a debugger.
More recently, however, some microcontrollers have begun to include a built-in high-level programming language interpreter for greater ease of use. BASIC is a common choice, and is used in the popular BASIC Stamp MCUs (Master Control Unit). Microcontrollers trade away speed and flexibility to gain ease of equipment design and low cost. There's only so much room on the chip to include functionality, so for every I/O device or memory increase the microcontroller includes, some other circuitry has to be removed. Finally, it must be mentioned that some microcontroller architectures are available from many different vendors in so many varieties that they could rightly belong to a category of their own. Chief among these are the 8051 family.