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Wireless 3D Glasses

Maintain Sync Without An IR Transmitter
 
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Hello,

I am sure that you intelligent people at the Halfbakery are familiar with stereoscopic 3-D shutter glasses for computers and video game consoles (i.e., cycle LCD lenses on and off in sync with “left” and “right” views on the display screen). The synchronization is maintained in one of two ways: (a) through a hard-wired connection between the computer/game console and the shutter glasses; or (b) through a wireless link (e.g., infrared) between an IR transmitter controlled by the computer/game console and the shutter glasses.

The hardwired link is not too interesting and obviously impedes freedom of movement (some people get really animated when playing video games). The wireless link requires a dedicated transmitter (e.g., an IR transmitter) to keep the shutter glasses in sync.

My idea is to: (a) initialize sync by having a detector (i.e., a visual light detector) in the shutter glasses detect one or more predetermined images on the display screen (a detector is needed in the shutter glasses anyway); and (b) maintain sync using circuitry on-board the shutter glasses.

This would provide a wireless link while eliminating the need for the dedicated IR transmitter (I think that the cost of the on-board circuitry would be substantially less than the cost of the dedicated IR transmitter). I know, not exactly an earth shattering idea, but maybe an idea nonetheless…

Testing_1_2_3, Dec 11 2002

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       What kind of "predetermined image" would it look for, and how? Could you do it cheaply, with just a light sensor, not an entire digital camera or whatever? If you can describe how that would work and how the subsequent synchronization would follow, then this sounds like a great idea.
egnor, Dec 11 2002
  

       No, no. No digital camera or such complicated mechanism. I am thinking of somthing like a sequence of black and white screens detected by a simple light sensor (visual light) held in the vicinity of the display screen.   

       Subsequent syncronization can take any well-known circuit design (e.g., PLL). The syncronization circuit does not have to be extremeny high-tolerance (in integrated circuit terms) since we are only talking about something on the order of magnitude of a 60 Hz refresh rate.
Testing_1_2_3, Dec 11 2002
  

       So for subsequent synchronization you're relying on the VBI? Sounds tricky; what if the scene happens to have dark areas which span the width of the display, or which overlap substantially with the front or back porch of the VBI?   

       You could require the constraint that a bar of light always remain at the top or bottom of the screen to provide a "handle" for synchronization but that's a little unfortunate.   

       Of course the whole LCD shutter thing requires a CRT display.
egnor, Dec 11 2002
  

       I see the subsequent synchronization being free-running (that is, not tied to the initial syncronization images or to the actual images being displayed for the viewer) - picture a clock in the shutter glasses telling each lens when to turn opaque and when to turn transparent   

       As far as the LCD shutter being tied to the CRT, I did warn you the idea is not earth shattering (although it seems to have some possible utility)...
Testing_1_2_3, Dec 11 2002
  

       It would be free running but it would need to correct itself; I doubt the clocks would stay in sync for very long. You mentioned a PLL which lead me to believe there is at least some amount of ongoing correction.
egnor, Dec 11 2002
  

       Not sure about necessarily losing sync (PLL was just an example), but thanks for the feedback.
Testing_1_2_3, Dec 11 2002
  

       //intelligent people//
That should read "person"
thumbwax, Dec 12 2002
  

       Oh, did somebody call for me ?
8th of 7, Dec 12 2002
  

       The glasses wouldn't have to be synched CONSTANTLY, using a pll, but you'd need some way to communicate the framerate then...
Corona688, Dec 12 2002
  
      
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