TV Remote Operated Domestic Appliances Control

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TV Remote Operated Domestic Appliances Control

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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

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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.

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Block Diagram

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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.

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Hardware Requirement

• POWER SUPPLY BLOCK
• MICROCONTROLLER (AT89S52/AT89C51)
• RC5 CODE
• RELAY
• ULN 2003
• TSOP

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Power supply
Bridge rectifier
230 V AC 50 Hz
5v Regulator

5V DC
Filter(470µf)
12V step down transformer
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Block diagram of MC

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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.

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MC components explanation
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.

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MC components explanation

• 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.

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Pin diagram of 8052

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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.

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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.

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RC5 CODE

• 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

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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

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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.

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ULN2003

• 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 Max500mA
• Voltage, Input Max5V
• Voltage, Output Max50V

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Relay

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

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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.

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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.

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