answer me please

Discussion in 'The Projects Forum' started by engahmad89, Jan 31, 2011.

  1. engahmad89

    Thread Starter New Member

    Jan 31, 2011
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    does the IR work affected incase of use it in sunny place?
    does deffere from using it in shadow places?
    how can i do the calculations of it in those cases?
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    1,728
    Yes, ambient light will affect IR operation. You can get around this by sending a series of pulses at a fixed frequency, and on the receiving end look for that frequency. The receiver looks at the difference between the two levels rather than the absolute level.

    Please use more meaningful subject lines in your posts, such as "IR reception in sunlight vs shadow question"
     
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  3. engahmad89

    Thread Starter New Member

    Jan 31, 2011
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    what calculations should i do in that case and how
     
  4. wayneh

    Expert

    Sep 9, 2010
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    We cannot guess what your goal is. Why do you think you need to calculate something?
     
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  5. engahmad89

    Thread Starter New Member

    Jan 31, 2011
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    i mean what calculations should i do for voltage required in each case
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    IR LEDs have a low Vf; usually somewhere around 1.2v.

    You are not being specific enough. Without knowing what all of the variables are, we cannot come up with any formulas for you.
     
  7. Audioguru

    New Member

    Dec 20, 2007
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    If sunlight is shining directly on your IR receiver then it will be saturated and will not detect pulses of IR that you send to it.
     
  8. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    This device detects the position of the cam and wire above it.

    [​IMG]

    It works in direct sunlight, mostly on Summer days. The detector, which points directly up and is located approximately at the short piece of blue tape works fine. The plastic cover is just some smoke-colored acrylic I had. It has worked well for the past 5 years.

    John
     
  9. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    If this is for a reflectance sensor, (not data transmission), the most common method is for the IR to transmit at 20kHz+, then use a high pass or band pass filter on the receiver so any continual or slow changing light (sunlight, flourescent lamps) is filtered out.
     
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