LED signs could soon hide secret messages

Discussion in 'privacy technology' started by guest, Aug 29, 2018.

  1. guest

    guest Guest

    LED signs could soon hide secret messages
    August 29, 2018
    https://www.engadget.com/2018/08/29/led-signs-could-soon-hide-secret-messages/
     
    guest, Aug 29, 2018
    #1
  2. mirimir

    mirimir Registered Member

    Joined:
    Oct 1, 2011
    Posts:
    9,252
    Wow. Very cool. One could also embed messages in third-party video :)
     
    mirimir, Aug 29, 2018
    #2
  3. caspian

    caspian Registered Member

    Joined:
    Jun 17, 2007
    Posts:
    2,363
    Location:
    Oz
    And some music so we could dance a little jig! *puppy*
     
    caspian, Aug 29, 2018
    #3
  4. brians08

    brians08 Registered Member

    Joined:
    Apr 27, 2008
    Posts:
    102
    LED data is true line of sight. You have to know where it is and then be in the light beam to pick up anything.
    The article says a single LED is only good a few inches but that makes no sense. Your flat screen remote uses a single LED and that works at 20' or more.
    Imagine a big animated sign with thousands of LED pixels. Take one LED and replace it with a wavelength slightly off from the rest and modulate the light pulses with data. Use a bandpass filter on the receiver to increase the SNR.
     
    brians08, Sep 6, 2018
    #4
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