2. INTRODUCTION
This main objective of this project is to use Infrared frequency
signal to control (on/off) the Home Appliances. This Project is
REMOTE CONTROLLED SWITCH BOARD, which is used to
switch on/off the Home Appliances by using a standard Remote
control. The system is used to switch on/off up to six electrical
devices. All the above processes are controlled by the 8 bit
Microcontroller AT89S52. The Microcontroller receives the
Infrared Signal from the receiver and it decodes and switch
on/off the appropriate Device. The Range of the system is unto
10 meters. The project can switch on/off electrical devices of
maximum load current of 5Amperes. High power loads can also
be connected by changing the Relay and the devices will come
to the original state after the power failure. The Microcontroller
is used receive the Infrared signal from the Transmitter, the
received signal is processed by the Microcontroller and
according to the signal the corresponding device is switched
On/off.
3. HARDWARE USED
1. 89S52 Microcontroller
2. Voltage regulator 7805.
3. Diode IN4007
4. IR Remote
5. T-SOP
SOFTWARE USED
1.Keil u-Vision 3.0
Keil Software is used provide you with software development
tools for 8051 based microcontrollers. With the Keil tools, you
can generate embedded applications for virtually every 8051
derivative. The supported microcontrollers are listed in the µ-
vision.
2. PRO51 Programmer Software
4. AN INTRODUCTION TO INFRARED
REMOTE:
Infrared (IR) light is electromagnetic radiation with
longer wavelengths than those of visible light, extending from
the nominal red edge of the visible spectrum at 0.74 micro
meters (µm) to 300 µm. This range of wavelengths corresponds
to a frequency range of approximately 1 to 400 THz, and
includes most of the thermal radiation emitted by objects near
room temperature. Infrared light is used in industrial, scientific,
and medical applications.
The main technology used in home remote controls
is infrared (IR). The signal between a remote control handset
and the device it is controlling are infrared pulses, which are
invisible to the human eye. The transmitter in the remote control
handset sends out a pulse of infrared light when a button is
pressed on the handset. A transmitter is often a light emitting
diode (LED) which is built into the pointing end of the remote
control handset. The infrared light pulse represents a binary code
that corresponds to a certain command, such as (power on). The
5. receiver passes the code to a microprocessor, which decodes it
and carries out the command.
First, infrared remotes have a range of only about 30 feet (10
meters), and they require line-of-sight. This means the infrared
signal won't transmit through walls or around corners -- you
need a straight line to the device you're trying to control. Also,
infrared light is so ubiquitous that interference can be a
problem with IR remotes. Just a few everyday infrared-light
sources include sunlight, fluorescent bulbs and the human body.
To avoid interference caused by other sources of infrared light,
the infrared receiver on a TV only responds to a particular
wavelength of infrared light, usually 980 nanometers. There are
filters on the receiver that block out light at other wavelengths.
Still, sunlight can confuse the receiver because it contains
infrared light at the 980-nm wavelength. To address this issue,
the light from an IR remote control is typically modulated to a
frequency not present in sunlight, and the receiver only responds
to 980-nm light modulated to that frequency. The system doesn't
work perfectly, but it does cut down a great deal on interference.
6. AN INTRODUCTION TO 8051
MICROCONTROLLER:
When we have to learn about a new computer we have to
familiarize about the machine capability we are using, and we
can do it by studying the internal hardware design (devices
architecture), and also to know about the size, number and the
size of the registers.
A microcontroller is a single chip that contains the
processor (the CPU), non-volatile memory for the program
(ROM or flash), volatile memory for input and output (RAM), a
clock and an I/O control unit. Also called a "computer on a
chip," billions of microcontroller units (MCUs) are embedded
each year in a myriad of products from toys to appliances to
automobiles. For example, a single vehicle can use 70 or more
microcontrollers. The following picture describes a general
block diagram of microcontroller.
7. BLOCK DIAGRAM OF PROJECT
8051
MICRO
CONTROLL
ER
POWER
SUPPLY
IR
REMOTE
TSOP
RELAY’S
RELAY’S
RELAY’S
RELAY’S
RELAY’S
RELAY’S
