Home Automation using Digital Control (1)

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Home Automation using Digital Control

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Home Automation using Digital Control
ABSTRACT

• Here is a teleremote circuit which enables
  switching on and off of appliances through
  telephone lines. It can be used to switch
  appliances from any distance, overcoming the
  limited range of infrared and radio remote
  controls.
• The circuit can be used to switch up to nine
  appliances (corresponding to the digits 1 through
  9 of the telephone key-pad). The DTMF signals on
  telephone instrument are used as control signals.
  
• The digit 0 in dtmf mode is used to toggle
  between the appliance mode and normal telephone
  operation mode. Thus the telephone can be used to
  switch on or switch off the appliances also while
  being used for normal conversation

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Home Automation using Digital Control
Block Diagram

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Home Automation using Digital Control
Hardware Requirements

• POWER SUPPLY BLOCK
• 555 TIMER
• RELAY
• MT8870 DTMF DECODER
• CD4049 INVERTER
• CD4013 FLIP FLOP
• MCT2E OPTO-ISOLATOR
• 74LS154
• BC547
• NPN TRANSISTOR

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Home Automation using Digital Control
Power Supply
Bridge rectifier
230 V AC 50 Hz
5v Regulator

5V DC
Filter(470µf)
12V step down transformer
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Home Automation using Digital Control
555 TIMER
The 555 Has Three Operating Modes

• Monostable mode
• In this mode, the 555 functions as a "one-shot".
  Applications include timers, missing pulse
  detection, switches, touch switches, frequency
  divider, capacitance measurement, pulse-width
  modulation (PWM) etc.

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Home Automation using Digital Control

• Astable
• The 555 can operate as an oscillator. Uses
  include LED and lamp flashers, pulse generation,
  logic clocks, tone generation, security alarms,
  pulse position modulation, etc.
• Bistable mode or Schmitt trigger
• The 555 can operate as a flip-flop, if the DIS
  pin is not connected and no capacitor is used.
  Uses include bounce free latched switches, etc.

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Home Automation using Digital Control
CD4049-Inverter

• The CD4049 devices are inverting hex buffers, and
  feature logic level conversion using only one
  supply voltage (VCC)
• These devices are intended for use as CMOS to
  DTL/TTL converters and can drive directly two
  DTL/TTL loads

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Home Automation using Digital Control
DTMF Decoder

• This circuit detects the dial tone from a
  telephone line and decodes the keypad pressed on
  the remote telephone.
• Two distinct frequency tones make up the
  DTMF(dual tome multiple frequency), and hence the
  name.
• The dialer and the telephone exchange communicate
  one way through the DTMF communication.
• The tone generator and the tone decoder consist
  of a complete communication setup.
• In this project, IC MT8870DE is used to decode
  the input dial tone to the dialed numbers.

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Home Automation using Digital Control

• These digital bits are interfaced to a
  microcontroller for any application.
• Pulse/dial tone method is used in the modern
  telephone communication.
• There is a dial tone generator on the caller side
  and a unique tone consisting of two audible tone
  frequency is generated when the user presses a
  button.
• As an example, 697hz 1209hz will be generated
  when key '1' is being pressed on the phone.
• A decoder circuit is present on the receiver
  side, which decodes the tone to a digital code.

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Home Automation using Digital Control
CD4013 Flip Flop

• The CD4013B dual D-type flip-flop is a monolithic
  complementary MOS (CMOS) integrated circuit has
  two D-type flip-flops, which you can use
  independently
• A D-type flip-flop, also called a D-type
  bistable, is a subsystem with two stable states.
  Using appropriate input signals, you can trigger
  the flip-flop from one state to the other.

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Home Automation using Digital Control
OPTO-Isolator

• Opto coupler is a 6 pin IC.
• It is a combination of 1 LED and a transistor.
• when light falls on the Base-Emitter junction
  then it switches pin5 goes to zero.
• When logic zero is given as input then the light
  doesnt fall on transistor so it doesnt conduct
  which gives logic zero as output.
• When logic 1 is given as input then light falls
  on transistor so that it conducts, that makes
  transistor switched ON and it forms short circuit
  this makes the output is logic zero as
  collector of transistor is connected to ground.

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Home Automation using Digital Control
OPTO-Isolator

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Home Automation using Digital Control
BC547

• The BC547 transistor is an NPN Epitaxial Silicon
  Transistor.
• The BC547 transistor is a general-purpose
  transistor in small plastic packages.
• It is used in general-purpose switching and
  amplification BC847/BC547 series 45 V, 100 mA NPN
  general-purpose transistors.
• Whenever base is high, then current starts
  flowing through base and emitter and after that
  only current will pass from collector to emitter

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Home Automation using Digital Control
74LS154

• Each of these 4-line-to-16-line decoders utilizes
  TTL circuitry to decode four binary-coded inputs
  into one of sixteen mutually exclusive outputs
  when both the strobe inputs, G1 and G2, are LOW
• The DE multiplexing function is performed by
  using the 4 input lines to address the output
  line, passing data from one of the strobe inputs
  with the other strobe input LOW. When either
  strobe input is HIGH, all outputs are HIGH.
• These DE multiplexers are ideally suited for
  implementing high-performance memory decoders.
  All inputs are buffered and input clamping diodes
  are provided to minimize transmission-line
  effects and thereby simplify system design.

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Home Automation using Digital Control
74LS154

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Home Automation using Digital Control
Circuit Diagram

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Home Automation using Digital Control
Circuit Explanation

• This system is designed to provide control of
  home appliances through landline by dialing the
  designated number for the particular load.
  Dialing can be done from the home phone or a call
  made to the home number from outside. This system
  is designed without engaging a programmable
  microcontroller but is based on digital logic
  using DTMF technology (Dual Tone multiple
  frequency) which receives the command from the
  landline phone to develop digital output.
• This digital signal is further processed to
  actuate switching mechanism through relay driver
  to turn on/off the loads/appliances. It can be
  used to switch appliances from anywhere,
  overcoming the limited range of other infrared
  and radio frequency type controls. This proposed
  system gives a new direction to the development
  of home automation. 

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Home Automation using Digital Control
Advantages

• High sensitive
• Works with any Cell phone from anywhere
• Low cost and reliable circuit
• Coverage distance up to 10 meter

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Home Automation using Digital Control
Applications

• Home appliances control
• Hotel lights/ fans Control
• Shops and Showrooms appliances control
• Industrial appliances

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Home Automation using Digital Control
Conclusion

• The concept of this system can be extended in
  future by giving an acknowledgement message to
  the user by system on the status of loads by
  using GSM modem.
• Home Automation using Digital Control Project is
  very helpful in Home, Industrial,Hotels and Show
  rooms

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