This document describes a home automation project that allows controlling home appliances like a TV, refrigerator, and lights using a personal computer. A PC is interfaced with a microcontroller via an RS232 cable. The microcontroller is connected to relays that switch appliances on and off. Home automation provides network connectivity between computers, appliances, and subsystems like HVAC and security. The project allows remote control and monitoring of appliances for convenience and energy savings.

1. HOME AUTOMATION USING PC DONE BY RAJESHKUMAR S SRI HARSHA D

2. MAIN APPLICATION OF PROJECT The aim of the project is to control home appliances like Television, Refrigerator, and Lights and other home electrical appliancesusing a personal computer. In this project a PC is interfaced with a micro-controller and it is connected to relays to which the appliances which are to be controlled are connected. The micro-controller controls the relays for switching the appliances, ON or OFF. Pre-defined symbols are sent to the Microcontroller through RS232 cable

4. smart chip bearing household appliances likedish washers, washing machines, microwaves and other electrical appliances.

7. Security

8. Cost Saving

10. MICROCONTROLLER VS MICROPROCESSOR Microprocessors and microcontrollers are widely used in embedded systems products. Microcontroller is a programmable device. A microcontroller has a CPU in addition to a fixed amount of RAM, ROM, I/O ports and a timer embedded all on a single chip. The fixed amount of on-chip ROM, RAM and number of I/O ports in microcontrollers makes them ideal for many applications in which cost and space are critical.

12. INTERNALARCHITECTURE All upgraded microcontrollers use one of two basic design models called Harvard and von-Neumann architecture VON-NEUMANN ARCHITECTURE Microcontrollers using this architecture have only one memory block and one 8-bit data bus. As all data are exchanged by using these 8 lines, this bus is overloaded and communication itself is very slow and inefficient The CPU can either read an instruction or read/write data from/to the memory. Both cannot occur at the same time since the instructions and data use the same bus system

13. HARVARD ARCHITECTURE Microcontrollers using this architecture have two different data buses. One is 8-bit wide and connects CPU to RAM memory. Another one consists of several lines (12, 14 or 16) and connects CPU to ROM memory Accordingly, the CPU can read an instruction and perform a data memory access at the same time

14. PIN Diagram Of Micro Controller Of AT89S8252

15. TIMERS SFR’S USED IN TIMERS: The special function registers used in timers are TMOD Register TCON Register Timer(T0) & timer(T1) Registers

16. TMOD Register: TMOD is dedicated solely to the two timers (T0 & T1). The timer mode SFR is used to configure the mode of operation of each of the two timers. Using this SFR your program may configure each timer to be a 16-bit timer, or 13 bit timer, 8-bit auto reload timer, or two separate timers. It can consider as two duplicate 4-bit registers, each of which controls the action of one of the timers.

17. TCON Register The timer control SFR is used to configure and modify the way in which the 8051’s two timers operate. This SFR controls whether each of the two timers is running or stopped and contains a flag to indicate that each timer has overflowed. Additionally, some non-timer related bits are located in TCON SFR. These bits are used to configure the way in which the external interrupt flags are activated, which are set when an external interrupt occurs.

18. CONCLUSION By using this project we control all the Electrical appliances of Home using PersonalComputer via RS232 as the communication medium between pc and controller. We are controlling the devices like light and fan and etc by sending signals from the pc to controller. This project gives exact concept of interfacing a high voltage electrical device or DC / AC motor to high sensitive personal computer system.

19. Thank You