Why do most HMDs have a separate control box? Or don't they?

[RejutkaLupex]

The title isn't ideal, there wasn't enough space to better phrase the second sentence...

My impression of HMDs (both 2D and 3D) is that almost all of them seem to have separate controller boxes that do the actual preparation/conversion for the displays, contain the battery, etc...

Why is that? Am I merely not seeing all the HMDs without controller boxes?
I can somewhat understand the need for a separate box to have buttons and the like - but even devices that cannot control anything (the Vuzix comes to mind) have a separate controller where you plug in your source.

Is using technology that fits inside the "glasses" so expensive or heavy?
One reason I could see would be easier replacement of the control hardware, but while that may be a good reason in theory, I can't imagine any company actually thinking about that, or average customers worry about replacing the controller to update it.

Of course, the battery is another good reason - no doubt it's easier to stuff a useful battery into a separate box than trying to balance it all on the users nose. But then I'm thinking about the ST1080, and wonder anew - it has no battery, no media player, "merely" the common conversion hardware/software that any HMD needs - why does it need a separate box?

[brantlew]

I think size and weight constraints keep it out of the small form factor devices like the Vuzix or the ST1080. Sony could have done it with their big form factor but were just lazy. I guess you have to consider cabling as well. Most HDMI and VGA cables are monstrosities and I wouldn't want the weight of them tugging at my head.

Another reason is for the menu systems that you have to traverse to configure 3D settings - although I can easily imagine a set of buttons on the side of the glasses that would work almost as well.

[suckmysound]

if the 3D is not a priority then fatsharks are great.
they do not have control boxes at all to mess with.
u plug-in the AV cable in AV-in and the charger to power in port. Can be powered off battery as well.
i wanted to buy avaiator version[46FOV] [usd$370] but upon learning that SVGA version will be coming out shortly this year - i halted.

WoW - SVGA [800x600] version with 46FOV and great 'dominator' optics will be a killer 2D HMD.

[cybereality]

Mostly I think its just a matter of size and weight. When you are wearing something on your head every ounce counts. But not every HMD is like this. If I remember correct the Vuzix VR920 did not have a control box. All it had was a single fixed cable that split off into VGA and USB. And the headset itself was still pretty small and light. So it can be done.

[RejutkaLupex]

I guess you have to consider cabling as well. Most HDMI and VGA cables are monstrosities and I wouldn't want the weight of them tugging at my head.

Hm. Good point.
Though I guess it should be possible to create a small adapter that simply leads to a thin cable discarding anything not really important (like shielding, for short distances); of course, this might lead to a controller box - thinking that if you have to have an adapter, why not go all the way and reduce weight on the HMD itself.

But not every HMD is like this. If I remember correct the Vuzix VR920 did not have a control box.

I know several devices that don't have a controller - like the one I bought - it's self-contained. But they seem to be in a minority.
Vuzix has a controller too - just checked their site - it even has buttons for some reason (I doubt you can control the source, so it must be used for the HMD - but what for?).

[brantlew]

Vuzix has a controller too - just checked their site - it even has buttons for some reason (I doubt you can control the source, so it must be used for the HMD - but what for?).

You can configure screen settings like brightness and so forth, but the primary reason for it is to switch 3D modes. (SBS, interleaved, etc.) So if you start watching a SBS youtube video, you have to toggle the mode switch to SBS on the Vuzix and then back again when you return to the desktop.

[Johnny-Mnemonic]

Vuzix has a controller too - just checked their site - it even has buttons for some reason (I doubt you can control the source, so it must be used for the HMD - but what for?).

VR920 doesn't have a control box. Wrap 920 VR have.
I still own one VR920, and I think design wise (size, weight) it's great. But of course it have lot's of technical issues.