help,CFL light interferes with IR sensor

Discussion in 'The Projects Forum' started by aruna1, Sep 1, 2009.

  1. aruna1

    Thread Starter Active Member

    Dec 20, 2008
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    hello guys i made a remote fan regulator.today i attach it to wall and connected to fan.its working fine except its IR sensor activates by CFL in my room(doesnt give any problem f i use incandesent light).i use VS1838 IR receiver.and i dont send data only single pulse to activate.somehow CFL light interfears with sensor.any idea how to overcome this?[​IMG]
    thanks
     
  2. rjenkins

    AAC Fanatic!

    Nov 6, 2005
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    That appears to be a problem with the design.

    There are many sources of infra-red, which is why IR remote controls normally use binary code schemes with some form of valid data checking and/or 'tell-me-twice' check.

    A filament bulb changes brightness relatively slowly as the filament heats and cools. A CF lamp can change brightness much faster and that particular type must just hit the receiver right...

    You may find a different make of CF lamp does not have the same effect, but without an error checking receiver you will probably still get random operations.

    The only complete cure may be to remove the IR sensor and look for a different remote control project, with an output you can connect across the fan push button position to give 'proper' remote operation.
     
  3. jj_alukkas

    Well-Known Member

    Jan 8, 2009
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    Yes, as Rjekins said, you need to add 'parity bit' coding, or an error correction technique to check if a recieved code is right. But as I read, I think I saw that ur uC was out of memory for more code.

    If the remote was also made by you, try building it using 2 555's with proper 38Khz modulation and programme your reciever to only respond to your remote's commands.

    The NEC coding technique if used would solve all your problems if you are really concerned about it.
     
  4. bertus

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    Apr 5, 2008
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  5. jpanhalt

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    Jan 18, 2008
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  6. aruna1

    Thread Starter Active Member

    Dec 20, 2008
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  7. jpanhalt

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    Jan 18, 2008
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    I was not talking about the 38 KHz carrier modulation of the IR. I was talking about modulation of that carrier as described in the datasheet for the TSOP detectors. That makes for easy correction for interferences.

    Apparently, you got it working as is, but if you have further problems with range or interference, please do consider the additional step. It is quite easy to do, particularly with an MCU.

    John
     
  8. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    The TSOP sensor also requires proper power supply decoupling as shown in the datasheet.
     
  9. aruna1

    Thread Starter Active Member

    Dec 20, 2008
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    well actually i dont have enough memory left in PIC to decode
     
  10. aruna1

    Thread Starter Active Member

    Dec 20, 2008
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    i added a pull up resistor and it seems problem is solved
     
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