TV Remote Operated Domestic Appliances Control

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TV Remote Operated Domestic
Appliances Control

Abstract
 A typical TV remote sends coded infrared data that is read by a IR
sensor with the help of a Microcontroller.
 This is traditionally RC5 code as followed by remotes from PHILIPS.
 The same data is then burnt to a microcontroller to drive desired
output load through relays or opto isolators and triacs.
 All the buttons of the remote can be used for as much number of
loads to be operated.
 All the above functions are monitored and controlled by the 8 bit
microcontroller

Introduction
 The project is designed to operate electrical loads using a TV
remote.
 The remote transmits coded infrared data which is then received by
a sensor interfaced to the control unit.
 The system operates electrical loads depending on the data
transmitted from the TV remote.
 Operating conventional wall switches is difficult for elderly or
physically handicapped people.
 This proposed system solves the problem by integrating house hold
appliances to a control unit that can be operated by a TV remote.

Block Diagram

Working
 The project uses an IR receiver such a TSOP-1738 that responds to
only specific frequency of 38 kHz in order to avoid receiving false
signal from normal environmental infrared sources.
 The output of this receiver in interfaced to port 3.0 of the
microcontroller.
 A standard TV remote that delivers infrared codes at 38khz is thus
received by the TSOP receiver feeding a 14 bit data so emitted from
the remote to the microcontroller through receiver.
 The output from the MC is fed to the relay driver IC to switch ON &
switch OFF the load as sent from the TV remote.

Hardware Requirement
 POWER SUPPLY BLOCK
 MICROCONTROLLER (AT89S52/AT89C51)
 RC5 CODE
 RELAY
 ULN 2003
 TSOP

230 V AC
50 Hz
Bridge rectifier
Filter(470µf)
5v Regulator
5V DC
12V step down
transformer
Power supply

CPU
On-chip
RAM
On-chip
ROM for
program
code
4 I/O
Ports
Timer 0
Serial
PortOSC
Interrupt
Control
External interrupts
Timer 1
Timer/Count
er
Bus
Control
TxD RxDP0 P1 P2 P3
Address/Data
Counter
Inputs
Block diagram of MC

MC components explanation
ROM:
 A code of 4K memory is incorporated as on-chip ROM in 8051.
RAM:
 The 8051 microcontroller is composed of 128 bytes of internal RAM.
Interrupt Control:
 An event which is used to suspend or halt the normal program
execution for a temporary period of time in order to serve the
request of another program or hardware device is called an
interrupt.

Parallel Input/Output Ports:
PORT P0: When there is no external memory present, this port acts as
a general purpose input/output port.
PORT P1: This port is used for various interfacing activities.
PORT P2: This port can be used as a general purpose port when there
is no external memory but when external memory is present it works
in conjunction with PORT PO as an address bus.
PORT P3: PORT P3 behaves as a dedicated I/O port.

Address Bus:
 A bus is group of wires using which data transfer takes place
from one location to another within a system.
Timers and Counters:
 Synchronization among internal operations can be achieved with
the help of clock circuits which are responsible for generating
clock pulses.
 Internal operations can be synchronized using clock circuits
which produce clock pulses.

Pin diagram of 8052

8052 pin diagram explanation
Port 0(p0.0 to p0.7):
 It is 8-bit bi-directional I/O port. It is bit/ byte addressable. During
external memory access, it functions as multiplexed data and low-
order address bus AD0-AD7.
Port 1 (p1.0 to p1.7):
 It is 8-bit bi-directional I/O port. When logic '1' is written into port
latch then it works as input mode. It functions as simply I/O port
and it does not have any alternative function.

8052 pin diagram explanation
Port 2 (p2.0 to p2.7):
 It is 8-bit bi-directional I/O port. It is bit/ byte addressable.
Port 3(p3.0 to port 3.7):
 It is 8-bit I/O port. In an alternating function each pins can be used
as a special function I/O pin.
RESET:
 It is active high I/P signal. It should be maintained high for at least
two machine cycle while oscillator is running then 8051
microcontroller resets.

 A common used standard protocol for infrared data communication is
the RC5 code, originally developed by Phillips.
 This code has an instruction set of 2048 different instructions and is
divided into 32 address so this makes it possible to change the
volume of the TV without change the volume of the hifi.
 The transmitted code is a data word which consists of 14 bits and is
defined as:
 2 start bits for the automatic gain control in the infrared receiver.
 1 toggle bit (change every time when a new button is pressed on
the ir transmitter
 5 address bits for the system address
 6 instruction bits for the pressed key
RC5 CODE

TSOP1738 Features
 Photo detector and preamplifier in one
package
 Internal filter for PCM frequency
 Improved shielding against electrical field
disturbance
 TTL and CMOS compatibility
 Output active low
 Low power consumption
 High immunity against ambient light
 Continuous data transmission possible (up
to 2400 bps)
 Suitable burst length .10 cycles/burst

TSOP17 Description
 The TSOP17 – series are miniaturized receivers for infrared remote
control systems.
 PIN diode and preamplifier are assembled on lead frame, the
epoxy package is designed as IR filter.
 The demodulated output signal can directly be decoded by a
microcontroller.
 TSOP1738 is the standard IR remote control receiver series,
supporting all major transmission codes.

 ULN2003 is a high voltage and high current Darlington transistor
array.
 It consists of seven NPN Darlington pairs that feature high-voltage
outputs with common-cathode Clamp diode for switching
inductive loads.
 The ULN2003 has a 2.7kW series base resistor for each Darlington
pair for operation directly with TTL or 5V CMOS devices.
 Current, Output Max:500mA
 Voltage, Input Max:5V
 Voltage, Output Max:50V
ULN2003

It is a electro magnetic switch
Used to control the electrical devices
Copper core magnetic flux plays main role here
Relay

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.

Conclusion
 The TV Remote Operated Domestic Appliances Control can be
enhanced by using radio frequency technology where the
operational range shall be independent of line of sight distance as
often encountered with IR type of remote control.
 Here Edgefx provides you a lot of information about electrical
instruments that are particularly useful for all Engineering
students.

TV Remote Operated Domestic Appliances Control

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