1. RF BASED HOME AUTOMATION SYSTEM
Project Title
RF BASED HOME AUTOMATION SYSTEM
Under the Guidance of
Submitted by

2. ABSTRACT
The main objective of the project is automation of home loads using RF technology.
In order to achieve this, a programmable microcontroller of 8051 family is used.
It consists of two sections: transmitter and receiver. The transmitter section consists of switches to ON/OFF loads.
This signal is encoded and transmitted using RF transmitter.
These signals are received by the receiver and decoder decodes the signal and this data is fed to MC which gives signal to the opto-isolator and triac arrangement to switch ON/OFF the loads.

3. BLOCK DIAGRAM
Transmitter section

4. Receiver Section

5. HARDWARE REQUIREMENTS
POWER SUPPLY BLOCK
MICROCONTROLLER AT89S52/AT89C51
RF TRANSMITTER & RF RECEIVER (HT12E/HT12D)
OPTO-ISOLATOR
REGULATORS
CRYSTAL OSCILLATOR
DIODES
RESISTORS
CAPACITORS
LAMPS

6. POWER SUPPLY Bridge rectifier 5v Regulator 230 V AC 50 Hz 5V DC
Filter(470µf)
12V step down
transformer

7. It is a smaller computer Has on-chip RAM, ROM, I/O ports...
MICROCONTROLLER
It is a smaller computer
Has on-chip RAM, ROM, I/O ports...
RAM
ROM
I/O Port
Timer
Serial COM Port
Microcontroller
CPU
A single chip

8. INTERNAL STRUCTURE OF A MICRO CONTROLLER-AT89S52/51
CPU
On-chip RAM
On-chip ROM for program code
4 I/O Ports
Timer 0
Serial Port
OSC
Interrupt Control
External interrupts
Timer 1
Timer/Counter
Bus Control
TxD RxD
P0 P1 P2 P3
Address/Data
Counter Inputs

9. Features of AT89S51/52 Compatible with MCS®-51 Products
8K Bytes of In-System Programmable (ISP) Flash Memory
Endurance: 10,000 Write/Erase Cycles
4.0V to 5.5V Operating Range
Fully Static Operation: 0 Hz to 33 MHz
256 x 8-bit Internal RAM
32 Programmable I/O Lines
Three 16-bit Timer/Counters
Eight Interrupt Sources
Full Duplex UART Serial Channel
Interrupt Recovery from Power-down Mode
Watchdog Timer
Dual Data Pointer

10. Pin Description

11. RF Transmitter and Receiver
RF modules are normally divided into three groups, RF transmitter module, RF receiver module and RF transceiver module
433MHz ASK transmitter and receiver is used for the remote control.
Fig : RF Transmitter
Fig RF Receiver

12. Features of RF Range in open space(Standard Conditions) : 100 Meters
RX Receiver Frequency : 433 MHz
RX Typical Sensitivity : 105 Dbm
RX Supply Current : 3.5 mA
RX IF Frequency : 1MHz
Low Power Consumption
Easy For Application
RX Operating Voltage : 5V
TX Frequency Range : MHz
TX Supply Voltage : 3V ~ 6V
TX Out Put Power : 4 ~ 12 Dbm

13. HT 12 ENCODER Operating voltage is 2.4V~12V for the HT12E.
Features
Operating voltage is 2.4V~12V for the HT12E.
Low power and high noise immunity CMOS technology
Low standby current: 0.1_A (typ.) at VDD=5V
HT12A with a 38kHz carrier for infrared transmission medium
Minimum transmission words are Four words for the HT12E
Built-in oscillator needs only 5% resistor
Data code has positive polarity
Minimal external components
HT12A/E: 18-pin DIP/20-pin SOP package

14. HT12 DECODER Features Operating voltage: 2.4V~12V.
Low power and high noise immunity CMOS technology.
Low standby current.
Capable of decoding 12 bits of information.
Binary address setting.
Address/Data number combination for HT12D: 8 address bits and 4 data bits.
Valid transmission indicator
Minimal external components
18-pin DIP, 20-pin SOP package

15. BC547 (NPN –Transistor)
The BC547 transistor is an NPN Epitaxial Silicon Transistor.
It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors.
The ratio of two currents (Ic/Ib) is called the DC Current Gain of the device and is given the symbol of hfe or nowadays Beta, (β).

16. The current gain from the emitter to the collector terminal, Ic/Ie, is called Alpha, (α), and is a function of the transistor itself

17. Opto-isolator Opto-coupler MOC3061/63 an LED SCR type combination.
Opto coupler is a 6 pin IC.
Additionally while using this IC with microcontroller and one LED can be connected in series with IC LED to indicate when high is given from micro controller such that we can know that current is flowing in internal LED of the opto-IC.
When logic high is given current flows through LED from pin 1 to 2 .So in this process LED light falls on SCR causing 6 & 4 to close only at the zero cross of the supply voltage.

18. Contd….
During each half cycle current flows through scr gate, external series resistor and through opto-scr for the main thyristor / triac to trigger for the load at the beginning of the supply cycle always to operate.

19. Software Requirements
Keil an ARM Company makes C compilers, macro assemblers, real-time kernels, debuggers, simulators, integrated environments, evaluation boards, and emulators for ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU families.
Compilers are programs used to convert a High Level Language to object code. Desktop compilers produce an output object code for the underlying microprocessor, but not for other microprocessors.

20. i.e the programs written in one of the HLL like ‘C’ will compile the code to run on the system for a particular processor like x86 (underlying microprocessor in the computer).
For example compilers for Dos platform is different from the Compilers for Unix platform  So if one wants to define a compiler then compiler is a program that translates source code into object code.

21. BIBILOGRAPHY
“The Microcontroller and Embedded systems” by Muhammad Ali Mazidi and Janice Gillispie Mazidi , Pearson Education.
ATMEL 89S52 Data Sheets.

22. QUERIES ?

23. THANKYOU