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Question about solar interference on laser tag guns

  1. May 13, 2012 #1
    So my brother had a birthday party the other day where this company that rents laser tag guns comes over and all his friends played a big game of laser tag outside. the guns worked surprisingly well, and there was even a "grenade" that would shoot lasers out in all directions once a pin was pulled. They were most likely IR lasers since I could not see a little dot on my hand when I shot myself, but the question is: I was surprised by how well the guns worked, despite solar interference; and I didn't know why so naturally I had to learn. Also, on a rant, would a "blue-ray laser gun" (blue laser) work better outside than a normal red or IR one? Because based on what science teacher said, blue light gets caught up in the atmosphere (turning it blue) and never makes it to earth, so my idea was that since there is no alien blue light coming to interfere, the game would work much smoother. Or am I getting this all wrong and red light DOES interfere with blue light. (actually, red and blue make purple...) ughh.. I dont even know what I'm saying anymore. Ill post now to get answers more quickly.
     
  2. jcsd
  3. May 13, 2012 #2

    Drakkith

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    Staff: Mentor

    The majority of blue light from the Sun reaches the surface of the Earth without scattering in the atmosphere. I don't think moving the laser from IR to visible would accomplish much, as the Sun's output is higher in the visible range than in the IR range. However I am not familiar with the workings of laser guns, so I could be wrong.
     
  4. May 14, 2012 #3
    It is possible that the Laser Tag sensors respond to coherent light only.
     
  5. May 16, 2012 #4
    Laser Tags guns do not use a laser for the actual tagging, but an infrared LED with a lens to focus the beam. The infrared is modulated with a 57.6 KHz carrier wave. The receiver detects this 57.6 KHz signal and isn't very sensitive to the IR wavelength.
    This works the same as Tv-remotes, only those have less power and the beams spread out more.

    see http://membres.multimania.fr/ormeralion/Fichiers/ctii.pdf

    esp. page 31: Infrared emitters and their driver circuitry
     
  6. May 16, 2012 #5
    Hmm, ok. Is there a wavelength of light that comes less powerfully from the cosmos?
     
  7. May 16, 2012 #6

    Drakkith

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    Staff: Mentor

    I'm not sure what you are asking. Less powerfully than what?
     
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