DDC glasses signal?

Post by **CarlKenner** » Tue Feb 26, 2008 10:07 am

What signal do nvidia cards send to DDC glasses? I'm trying to use WinI2C-DDC to do it, but I can't get it to work.

Post by **RAGEdemon** » Tue Feb 26, 2008 11:05 am

+5v 0v square wave 50% duty cycle. High = one eye is black, low is other side is black. Signal is on pin 12.

Post by **CarlKenner** » Thu Feb 28, 2008 1:07 pm

I can't get it to work with WinI2C-DDC.

Post by **RAGEdemon** » Thu Feb 28, 2008 1:15 pm

Can you be more specific?

Have you tried to get a signal on pin 12? If there is no signal then something wrong in your setup. If there is a proper signal then something wrong with your glasses.

If there is not the proper signal on the line then its a problem with the software and or hardware and you should ask the WinI2C-DDC people as its really nothing to do with stereo3D

I'm guessing its not producing the signal in the right format... I'm afraid you will need an oscilloscope to see what its actually producing. There are free software oscilloscopes available on the net which use a sound card... they work quite well but without a ground reference, you will see a signal of 2.5v and -2.5v instead of +5v and 0v.

Post by **CarlKenner** » Thu Feb 28, 2008 1:44 pm

I'm not sure I'm brave enough to wire up my vga port to my sound card, and I don't have an oscilloscope handy. But the SetSDA function returns true. I'm thinking maybe the problem is that the frame rate isn't high enough, or i'm calling the function at the wrong part of the rendering. Or does the nvidia card send some special signal to put it into stereo mode first?

Post by **Likay** » Thu Feb 28, 2008 2:57 pm

If you just want to check a squarewave at a low frequency you can try just adding a resistor and an led. Then swing the cable with the led back and forward. Since the led is moving you'll see the pattern it blinks with. (It's a quite rough estimation but i think this might be enough).

cheers

Post by **RAGEdemon** » Thu Feb 28, 2008 3:30 pm

LOL Likay, what a fantastic idea.

Have to try it myself sometime!

Post by **RAGEdemon** » Thu Feb 28, 2008 8:47 pm

As long as there is a square wave at the proper frequency, the glasses should "flicker". There is no "turn on" command for the glasses.

You don't have to wire it. Just temporarily affix a crocodile pin to the male end of a cable which is plugged into your VGA port.

Nothing on your card will break if you connect the wrong pin or short circuit a pin to another one.

For the oscilloscope thing, it uses the microphone port of your sound card. You don't really have to hack or solder anything. I have done it (and short circuited wrong pins accidentally *cough*) many times without any problems.

This looks like a decent one

http://www.zeitnitz.de/Christian/Scope/Scope_en.html

Let me know if you have any issues... this kinda I can actually help with. As for programming...you may as well be asking an apple

-- Shahzad.