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

2. The aim of the project is to control home appliances like Television, Refrigerator, and Lights and other home electrical appliances using 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 MAIN APPLICATION OF PROJECT

3. Home automation deals with providing a network in the house which links  computers & peripheral equipment.  smart chip bearing household appliances like dish washers, washing machines, microwaves and other electrical appliances.  sub-systems like Heating, Ventilation, Air- conditioning (HVAC), and security systems. What Is Home Automation

4. Micro Controller PCM MAX 232 Power supply ReLay Driver Relay FAN LIGHT Power supply BLOCK DIAGRAM

5. ADVANTAGES OF HOME AUTOMATION  Flexibility & Convenience  Security  Cost Saving  Remote Control

6. An embedded system can be defined as a computing device that does a specific focused job. Appliances such as the air-conditioner, VCD player, DVD player, printer, fax machine, mobile phone etc. are examples of embedded systems. Each of these appliances will have a processor and special hardware to meet the specific requirement of the application along with the embedded software that is executed by the processor for meeting that specific requirement. EMBEDDED SYSTEM

7. 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.

9. INTERNAL ARCHITECTURE 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

10. 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

11. PIN Diagram Of Micro Controller Of AT89S8252

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

13. 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.

14. 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.

15. By using this project we control all the Electrical appliances of Home using Personal Computer 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.