27-12-2012, 01:02 PM
A Project Report On HOME AUTOMATION
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Abstract:
With advancement of technology things are becoming simpler and easier for us. Automatic systems are being preferred over manual system. This unit talks about the basic definitions needed to understand the Project better and further defines the technical criteria to be implemented as a part of this project.
INTRODUCTION-
Home automation is the residential extension of "building automation". It is automation of the home, housework or household activity. Home automation may include centralized control of lighting, HVAC (heating, ventilation and air conditioning), appliances, and other systems, to provide improved convenience, comfort, energy efficiency and security. Home automation for the elderly and disabled can provide increased quality of life for persons who might otherwise require caregivers or institutional care.
A home automation system integrates electrical devices in a house with each other. The techniques employed in home automation include those in building automation as well as the control of domestic activities, such as home entertainment systems, houseplant and yard watering, pet feeding, changing the ambiance "scenes" for different events (such as dinners or parties), and the use of domestic robots. Devices may be connected through a computer network to allow control by a personal computer, and may allow remote access from the internet. Through the integration of information technologies with the home environment, systems and appliances are able to communicate in an integrated manner which results in convenience, energy efficiency, and safety benefits.
Although automated homes of the future have been staple exhibits for World's Fairs and popular backgrounds in science fiction, complexity, competition between vendors, multiple incompatible standards[1] and the resulting expense have limited the penetration of home automation to homes of the wealthy or ambitious hobbyists. Possibly the first "home computer" was an experimental home automation system in 1966
PASSWORD ACCESS SYSTEM
Security is prime concern in our day-today life. Every one wants to be as much as secure as to be possible. An access control system forms a vital link in security chain. The micro controller based digital lock present here is an access control system that allows only authorized persons to access a restricted area. The system comprises a small electronics unit with a numeric keypad, which is fixed out side the entry door to control a magnetic lock. When an authorized person enters predetermined number (password) via the keypad, the relay operated for a limited time to unlatched the magnetic lock so the door can be pushed/pulled to open. At the end of present delay, the relay reenergizes and the door gets locked again. If the entered password is correct the display displays that “ Code is correct – access allowed.” And if the entered password is wrong it gives three beep signals and display will displays “Code is in-correct – Access is denied”.
When the code has been incorrectly entered five times, the code lock will switch to alarm relay are turned off after entering a valid user Access code. This function thwarts any attempt by hackers to quickly try a large number of codes in a sequence. The secret code can be changed any time after entering the current code (Master code).
With advancement of technology things are becoming simpler and easier for us. Automation is the use of control systems and information technologies to reduce the need for human work in the production of goods and services. In the scope of industrialization, automation is a step beyond mechanization. Whereas mechanization provided human operators with machinery to assist them with the muscular requirements of work, automation greatly decreases the need for human sensory and mental requirements as well. Automation plays an increasingly important role in the world economy and in daily experience. Automatic systems are being preferred over manual system. Through this project we have tried to show automatic control of a house as a result of which power is saved to some extent.
NEED OF AUTOMATION
Earlier, we looked into the face of future when we talked about automated devices, which could do anything on instigation of a controller, but today it has become a reality.
An automated device can replace good amount of human working force, moreover humans are more prone to errors and in intensive conditions the probability of error increases whereas, an automated device can work with diligence, versatility and with almost zero error.
Replacing human operators in tasks that involve hard physical or monotonous work.
Replacing humans in tasks done in dangerous environments (i.e. fire, space, volcanoes, nuclear facilities, underwater, etc)
Performing tasks that are beyond human capabilities of size, weight, speed, endurance, etc
This is why this project looks into construction and implementation of a system involving hardware to control a variety of electrical and electronics system.
Power supply design
The first building block in the dc power supply is the full wave rectifier. The purpose of the full wave rectifier (FWR) is to create a rectified ac output from a sinusoidal ac input signal. It does this by using the nonlinear conductivity characteristics of diodes to direct the path of the current.
Peak Current Levels
Diodes in the bridge conduct only in the time period from T0 to T1. The diode current must replace the charge lost by the capacitor during its discharge.
I = dQ/dT = C*dV/dT
As the magnitude of the filter capacitor increases, the peak current through the diodes must increase to replace the charge in less time. Therefore it is not always best to choose the largest value of C1 available. In a dc power supply, you can rely on the stages following the FFWR to significantly improve the voltage regulation.
GENERAL DESCRIPTION:-
The ISSI IS89C52 is a high-performance microcontroller fabricated using high-density CMOS technology. The CMOS IS89C52 is functionally compatible with the industry standard 80C51 microcontrollers. The IS89C52 is designed with 8-Kbytes of Flash memory, 258 x 8 RAM; 32 programmable I/O lines; a serial I/O port for either ultiprocessor communications, I/O expansion or full duplex UART; three 16-bit timer/counters; an eight-source, two-priority-level, nested interrupt structure; and an on-chip oscillator and clock circuit. The IS89C52 can be expanded using standard TTL compatible memory.
A microcontroller is an entire computer manufactured on a single chip. Microcontrollers are usually dedicated devices embedded within an application e.g. as engine controllers in tomobiles and as exposure and focus controllers in cameras. In order to serve these applications, they have a high concentration of on-chip facilities such as serial ports, parallel input/output ports, timers, counters, interrupt control, analog-to-digital converters, random access memory, read only memory, etc. The I/O, memory, and on-chip peripherals of a microcontroller are selected depending on the specifics of the target application. Since microcontrollers are powerful digital processors, the degree of control and programmability they provide significantly enhances the effectiveness of the application. Embedded control applications also distinguish the microcontroller from its relative, the generalpurpose microprocessor. Embedded systems often require real-time operation and multitasking capabilities. Real-time operation refers to the fact that the embedded controller must be able to receive and process the signals from its environment as they are received. Multitasking is the capability to perform many functions in a simultaneous or quasi-simultaneous manner Random Access Memory (RAM): RAM is used for temporary storage of data during runtime.