Testing Ir sensor 4 8051

Discussion in 'General Electronics Chat' started by jokester4u, Mar 18, 2014.

  1. jokester4u

    Thread Starter New Member

    Nov 3, 2012
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    The sensor is giving only 1 how do i make it 0 . So it becomes off ...
     
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  2. wmodavis

    Well-Known Member

    Oct 23, 2010
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    1 what? .

    Might have to do with the fact that the OP Amp output is grounded. Therefore the input to the 80C51 is also grounded. Is that what you want?
     
  3. bertus

    Administrator

    Apr 5, 2008
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  4. jokester4u

    Thread Starter New Member

    Nov 3, 2012
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    Yes !!!! It's grounded which makes the led glow. So my question is how do I get 1 input that will switch off the led. Meanwhile the sensor work both ways either 1 or 0 but unfortunately its working here as 0 only.
     
  5. wmodavis

    Well-Known Member

    Oct 23, 2010
    737
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    It is impossible with the circuit you show because the output of U3A (LP339) is connected to the ground point and therefore cannot ever change from zero volts. It will always be zero volts. So since you state that YES!!!! you want it grounded you have what you want. Next question?
     
  6. jokester4u

    Thread Starter New Member

    Nov 3, 2012
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    Or please let me know how to make a working IR sensor in proteus?
     
  7. wmodavis

    Well-Known Member

    Oct 23, 2010
    737
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    For a starter DO NOT ground the output of the op amp. That prevents it from switching!
     
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