3D glasses (not the retarded red and blue kind)

[Dr. McSteinsworth]

@ the "you cannot change the emitted polarization of an lcd" guy: If LCD tv's emit polarized light, then you can use polarized glasses successfully to view a 3D image! Here's how: If you have the horizontal-vertical polarized ones, then all you need to do is simply hook up a motor to the tv and rotate it at half the frequency of the glass' frequency. You would also need to make a few adjustments to the output video so that the image for every 2nd frame is sideways, every 3rd is upside down, and every 4th is the 'other sideways'. The only thing is, everything would be a little blurry. Haha that would be a hilarious project.

 

[tcmtech]

I like the concept your talking about but again I am skeptical about the LCD drive devices.
If I recall the common method is an actual alternating current applied through the LCD. And by PWM the AC is how the actual dimming or shading can be accomplished.
Being the LCD's work on a microamp level I was thinking that the micro controller guys would have no problem designing a basic LCD driver system. That could be phased to some sort of sensor that could pick up the frame by frame flicker and translate that to an actual lens alternation.

Or am I way off?

As far as the welder helmet concept there is one fatal flaw in the sensor tapping idea. The off delay built into the actual driver circuit!
Most are .5 to 3 seconds! The on response is 1/20000 of a second but the off time is not. I have an auto dim helmet and did a few hours of welding today and just though I would pass that part along.
I forgot about the time delay in the off side of the control. To beat that you would still need to hack the circuit I think.

 

[Sceadwian]

Yer not way off, but shutter glasses are almost always directly connected to the machine and synced via software, although syncing directly from the video from a sensor on the front seems like a good idea though I'm not sure how practical it would be. The turn off delay is likely from a capacitor providing hold up power. LCD's only require close to 1 volt to change from light to dark, a simple voltage divider from a micro controller could easily switch them.

 

[tcmtech]

SO it is feasible to do. You may be right about The capacitor delay mechanism BUT...
I want to be there when you take a dremmel to a potted surface mount circuit board thats going to cost you $50+ if you oops! and hit something besides the right capacitor!

I had a control board out of a cheaper helmet once. It had some surface mount capacitors but as I recall most of the stuff looked like comparator and possibly micocontroller IC's Rather complex circuitry actually! And very very small too!

If a sensor based timing system was used couldn't a synchronizing effect be done just by seeing the last frame flash and the counting so may micro seconds until the nest frame flash should happen work?
Dont actually sync to the present frame but just sense it and anticipate when the next one is coming to give you an effective timing reference?

However to keep the reference to which lens was to be triggered with the right frame I would think that a periodic reference frame would be needed though. That way the right left switching would be held in the correct order.

 

[Torben]

Hi tcmtech,

You're completely right about the off delay--I had totally forgotten about that since my helmet lets you adjust it right down to zero. Cheap masks don't have that control. (Mine cost $300, which is a bit much to rip open for a prototype ). If the cheap mask didn't allow that to be set to zero then the idea is indeed fatally flawed.

Oh well. Thanks for pointing that out or I might have tried it one day!


Cheers,

Torben

 

[Sceadwian]

There's no flaw... Rip the control electronics out, all you need to power the LCD directly is voltage divider to set the bias. You'd want to drive it directly anyways.