IR Remote Decoder by Veu92qx4

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									IR Remote Decoder

     Egr 326H
    Doug Carlin
How IR works
        • IR is an invisible light
          that can transmit large
          amounts of
          information while
          preserving the
          uniqueness of each bit.
Remote Encoding Scheme
  Each Remote Uses an Encoding Scheme
  Since I chose a Sony remote, its scheme is using the pulse-width coded
  standard. Sony uses a 12-bit protocol that consists of a 4-bit ID code 4-
  bit command code followed by 3 bits to sync the data.


  “1) Pulse-Width-Coded Signals vary the length of pulses to code the
  information. In this case if the pulse width is short (approximately
  550us) it corresponds to a logical zero or a low. If the pulse width is
  long (approximately 2200us) it corresponds to a logical one or a high.
  “ Source
  http://www.ee.washington.edu/conselec/A95/projects/pierreg/main.ht
  m
                Objective
To study the signals emitted from a Sony
 remote control and create an interfacing
 device with the PC. The extension of this
 project being researched is a possible source
 for controlling household electronics
 through the web.
Motivation
  • With all remotes on the market (not to
    mention in the households it only
    makes sense to understand whether or
    not you actually need these advanced
    remotes or if you can replicate them.
    But how can you encode data that you
    cannot “see”. That is where the IR
    Remote Decoder comes

  • This project attempted to “see” the
    encoded data from a single remote and
    translate that back to what button/key
    was pressed (for under $50.00).

  • This may be used in the future to have
    a computer pc program to transmit the
    “button/key” to a device via a range
    extender possibly through the internet.
      Basic Design Diagram


                                      Pic
               Power
   Power       Supply
   Supply       Plug
                                                      Serial            PC
    (Wall                                                       RS232
                                                    Interface
Transformer)
               On/Off
               Power
               Switch

                                Infrared Detector
                 Infrared LED
Parts to Produce a Working
           Circuit
Software Implementation
   Start
  Routine




                Clear
               Memory



               Display
               Ready
                Signal

                                                END
               Wait for     no
                Signal      signa



                                            Store
  Timing                                 groups of 8
 Subroutine                              bits into a
                                            table



               Initalize
                Timer
                                    while n<9

                                             Store
              Start Timer                   Shifted
                                            Result



               Look for
                                            Set
                 pulse
                                           Counter
              transitions



                                           Shift bits/
              Stop Timer                  store timer
                                              info
The Source of Error
          Reasons it was picked:
          •   This transformer output is 9 Volts
              DC at 500mA. The voltage
              regulator used is a voltage regulator
              with a dropout voltage of 2 Volts.
              Therefore a voltage of at least 7
              Volts from the transformer must be
              used for the regulator to operate
              properly. The closer to 7 Volts the
              less differential voltage, thus less
              power lost as heat.
          •   Unfortunately the transformer put
              out 14 V and the circuitry was not
              able to handle the power
              dissipation.

								
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