12-07-2012, 01:29 PM
home security system
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Introduction:
Electronic code door locking system or Password based door locking system. To the human race in this situation, security is the prime concern in which a man wants to secure all his things. Now-a-days, everyone is opting for the more secured home, secured accounts, secured society which is impossible these days. The Password protected system is the most éclatic in these days. But the electronic developments are making it possible to find a way to make everyone feel free.
In the previous days, a home is secured when it had mechanical locks which be can opened only with a single key. Later it had become the least used.Its because of the disadvantage it is having. The key can be duplicated easily whoever wishes to do so. This problem has been overcome with the electronic devices. In this, a password can be set, with which a home is said to be secured. The password cannot be duplicated or hacked or can be known by any other means. This is the major advantage of this system. A stranger can easily breakdown the lock and enter into our premises. But with the password protected system, even his greatest tool cannot break the password. This system is of porcelain which cannot be easily got down.
In this age of digital technology, every device and operation has become digital based. Now with digital based door lock systems, it is easier to control the door movement of the car or house. The new automated door lock system does not need a key to lock or unlock the door of the car or house. This digital door entry system is in fact controlled by a keyless.
The keyless door remote is an electronic circuit based device. This remote transmits radio
Signals via air to another device of the system installed in the car door or house door. The remote device of most digital appliances can be operated with either single or double batteries.
The keyless car remote can be operated from a distance of up to 75 to 500 meter
The working of a keyless remote is similar to the remote of a digital music player system like LCD television. However, some advanced digital remotes of a car lock system work on the entry number. A car owner has to press that entry number on the remote for controlling the movement of his car doors. The entry number is unique in nature and so is the remote device of an automatic keyless system. The remote of one keyless system cannot work on another.
The special feature of a keyless automatic door system is that it cannot be opened or closed manually. This digital system also carries an alarm signal which starts beeping when the digital door of a vehicle or home is touched by anyone. This system is thus essential for preventing
You can install a keyless entry system in your house as well as in your vehicle. Now a day, theft cases are increasing everywhere and the key based locking system is no longer a safe option. It is quite easy for thieves and robbers to open the traditional key based doors either with duplicate keys or some other way. Therefore for complete safety of your house and vehicle, you should install digital security systems at both places. With this system, you will never be in tension of.
In case your keyless remote stops functioning or you forget to remember the entry code of the door system, you can get repair services of the keyless digital remote from a car dealer or licensed locksmith. If you are on a journey and have lost your car remote, then too you can get a replacement of your lost remote from a local car dealer. The keyless entry remote systems are compact in size and there are numerous companies that manufacture these security gadgets. You can buy integrated electronic door lock systems either from a shop.
Modern keyless car lock appliances are equipped with added functions such as fuel indicator, temperature indicator of the car, etc. Therefore for security and added functionalities, you should install the latest version of a digital remote system in your car. However, this security system is also not a safe option anymore as thieves are now using high tech encrypted software’s for unlocking the car doors. Cyberlock is an access control
system that increases key control and accountability throughout your organization. Based on a unique design of electronic lock cylinders and intelligent keys, Cyberlock solves security problems that no other system can. Cyberlock cylinders replace standard mechanical lock cylinders. Cylinders install without wiring, easily converting your existing lock hardware into an access control system.
Introduction:
The P89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 8K bytes of Flash programmable and erasable read only memory (EPROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 and 80C52 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the PHILIPS P89C51 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.
Interrupts:
The AT89C52 has a total of six interrupt vectors: two external interrupts (INT0 and INT1), three timer interrupts (Timers 0, 1, and 2), and the serial port interrupt. These interrupts are all shown in Figure 6. Each of these interrupt sources can be individually enabled or disabled by setting or clearing a bit in Special Function Register IE. IE also contains a global disable bit, EA, which disables all interrupts at once. Note that Table shows that bit position IE.6 is unimplemented. In the AT89C51, bit position IE.5 is also unimplemented. User software should not write 1s to these bit positions, since they may be used in future AT89 products.
Power-down Mode:
In the power-down mode, the oscillator is stopped, and the instruction that invokes power-down is the last instruction executed. The on-chip RAM and Special Function Registers retain their values until the power-down mode is terminated. The only exit from power-down is a hardware reset. Reset redefines the SFRs but does not change the on-chip RAM. The reset should not be activated before VCC is restored to its normal operating level and must be held active long enough to allow the oscillator to restart and stabilize.
PROTECTION DIODE:
If the load is a motor, relay or solenoid (or any other device with a coil) a diode must be connected across the load to protect the transistor from the brief high voltage produced when the load is switched off. The diagram shows how a protection diode is connected 'backwards' across the load, in this case a relay coil.