VR Gaming with HTC Vive / Other Headsets via USB-C! (VirtualLink, Thunderbolt 3)

[Pecacheu]

So this is a bit of an idea I had recently... Potentially even an idea for exploration in an LTT video! I've been thinking about how it would be possible to outfit the HTC Vive (the headset I have) with USB-C instead of the included cable.

 

Prologue: I had an opportunity a while ago to try out one of those wireless VR gaming backpack things in a store once that turns the Vive (I think it was the Vive version if I recall) into a wireless headset, and honestly... I could feel the lag vs a cable, it's just not the same. I just don't think the tech is there yet, even as impressive as all the fancy 5G or WiGig tech is... it's still not good enough.

 

So since I'm going to be sticking to cables for now, I was trying to think of ways to take that bulky tri-cable setup and turn it into a single USB-C cable, coming straight from the headset, that goes straight intro the PC.

 

VirtualLink is basically the failed attempt at a standard that is the reason NVIDIA puts USB-C connectors on their GPUs. It's a cool name but technically not the same thing as USB-C, it's an alt-mode. I believe the only difference to DisplayPort alt-mode is that it provides 2 DP lanes and a USB 3.2 lane instead of 1 DP lane and a USB 3.1 lane. (Though I might be wrong on the numbers there as there's conflicting info and even Wikipedia seems a little confused tbh)

 

Point is, there's liely barely any practical performance difference between them (5Gbps vs 10 for the USB, basically irrelevant, speed does not equal latency and only the latter matters much to VR sensors), so there's no real reason to stress out about not using purpose-built USB-C based adapters. And VirtualLink-compatible hardware is practically non-existent because it's basically a failed standard.

 

So with that out of the way, the problem we need to solve is carrying the USB 3, HDMI, and power for the headset all through a single cable. The first two are easy enough... It's the third that gets tricky. You might recall this adapter by Accell that made the headlines a little while ago, meant for adapting an Oculus Rift to using USB-C. But it only carries USB and HDMI, no power... Fine for the Rift since it can be powered by USB, but with the Vive, that barrel plug is required!

 

The HTC Vive is powered via it's Link Box by 12VDC at 2A... Though it will work basically fine off 1A from my own testing with a bench supply. Interestingly, it also seems to work fine at 9V 2A. Additionally, a surprising fact is that the Link Box is completely optional and unnecessary! The only requirement for using the Vive without the Link Box is that your PC has Bluetooth built-in, and that you can find a female barrel jack to sacrifice that happens to be the right size! (Btw, I've actually noticed slightly better performance without the Link Box in some cases, looks like the radios in it take up some of that precious bandwidth, lol)

 

Anyhow, that 12V power requirement is probably good news as that's a standard voltage for USB PD! So if the GPU's output port, or the USB-C port of a gaming laptop as another example, can supply 12V via USB PD then theoretically, this should be able to work. However, I have no clue if that's the case. For example the new laptop I've got (well, purchased, but it hasn't come in yet as it's a special order) lists the max wattage of the Thunderbolt 3 ports and claims to support USB PD (though doesn't say if that's for input only or both ways), but doesn't mention supported voltages anywhere. It can supply up to 15W, which would be 5V 3A or 12V 1.25A.

 

Of course, the next problem is what to do at the other end of the cable, the headset end. That's where a USB-C hub comes in! These are easy enough to find on the cheap, and any should do as long as it's got an HDMI port and USB 3.0. Here's one for $25 for example: https://amazon.com/dp/B07QXMNF1X I have one for example with 3 USB 3.0 ports and one 4K/60Hz HDMI. I like it because it doesn't have any of that useless bloat like a bunch of 2.0 ports and a multi-card reader. Just the essentials so it's nice and compact.

 

That said I haven't tested to ensure that it works with my headset, but I can confirm that (besides working with a phone which is what I bought it for) it works with a desktop through the USB-C port on the GPU. You can connect a display, USB 3.0 devices, and USB 2.0 devices, all at once, without a hitch. Of course that still doesn't solve our power delivery issue...

 

For that I think the solution might be one of these! That's a USB-C PD trigger, it simply tricks the USB-C device it's connected to into supplying the correct output voltage you want... assuming that device is capable of outputting said voltage. If we set it to 12V, then connecting it to the headset should allow a 12V supply over a single cable! The only thing to watch out for would be that the hub you're using provides a USB Type-C passthrough port compatible with USB PD (up to 100W of passthrough power). That should allow the higher voltage to pass through the cable while the lower-voltage 5V is simultaneously supplied to power the hub's own USB ports! Yup that's right, two voltages at once. It really works. Isn't USB-C freakin' amazing?

 

And that brings us to the final problem... Err, well... where the heck to find such a long USB-C cable! That I don't know, but I'm sure you could find one if you looked hard enough.

 

 

Alright so I know this is a long post but I'd love thoughts on this, not so much a question but I'm hoping to incite a discussion about um... odd VR and USB-C things.

[ki8aras]

assuming that you overcome all your previous hurdles i think you might need to buy sth like an active cable

[Pecacheu]

11 minutes ago, ki8aras said:

assuming that you overcome all your previous hurdles i think you might need to buy sth like an active cable

Yeah, most likely. Not sure what sorcery Accell is using to get their cable to 8ft long with that specialized VR dongle, but it may have some sort of built-in active cable in the adapter.

 

Oh, I neglected to mention... failing the solution of supplying 12V power from the desktop/laptop's own USB-C port, one could also use a USB-C powerbank, strapping it to your waist or putting it in your pocket for example. Since USB-C powerbanks with PD support can output not just the standard 5V, but 12V as well (and some up to 20V), you could use that in combination with the PD Trigger I mentioned above, and power the headset that way rather than through the cable itself. Plus, that solution might allow you to use an optical cable of some kind, which I imagine would be even lighter. (Wait, haha that was an unintentional pun)

[ki8aras]

3 minutes ago, Pecacheu said:

Yeah, most likely. Not sure what sorcery Accell is using to get their cable to 8ft long with that specialized VR dongle, but it may have some sort of built-in active cable in the adapter.

 

Oh, I neglected to mention... failing the solution of supplying 12V power from the desktop/laptop's own USB-C port, one could also use a USB-C powerbank, strapping it to your waist or putting it in your pocket for example. Since USB-C powerbanks with PD support can output not just the standard 5V, but 12V as well (and some up to 20V), you could use that in combination with the PD Trigger I mentioned above, and power the headset that way rather than through the cable itself. Plus, that solution might allow you to use an optical cable of some kind, which I imagine would be even lighter. (Wait, haha that was an unintentional pun)

don't optical cables support much bigger lengths?

if you have no regard for cost at least

[Pecacheu]

10 minutes ago, ki8aras said:

don't optical cables support much bigger lengths?

if you have no regard for cost at least

They do. But they also usually don't support USB PD I think. So you would have to power the headset via other means.

 

Also searing for USB-C cables can be difficult because there are so many different kinds, and you need one with 100% full support for all features or the dock will basically refuse to work at the other end. I've tried this, for example using a USB 2.0 Type-C cable with my own hub, it straight up refuses to work at all, but using a USB 3.2 Gen 2 cable or Thunderbolt 3 cable (same thing basically), it worked fine.

 

Thunderbolt 3 is easier to search for so I'm mainly trying that. I found a 2 meter (6.6ft) TB3 cable for $25. Though doing a mock-up with a 6.6ft charging cable I own, I've found that it's too short... Even a small room scale setup would make you tug your PC off the desk at that length, lol. So one would need to find a longer cable than that.

 

Though hey, if your basement happens to also be a Costco warehouse, apparently this cable exists: https://bhphotovideo.com/c/product/1522225-REG

[ki8aras]

4 minutes ago, Pecacheu said:

They do. But they also usually don't support USB PD I think. So you would have to power the headset via other means.

 

Also searing for USB-C cables can be difficult because there are so many different kinds, and you need one with 100% full support for all features or the dock will basically refuse to work at the other end. I've tried this, for example using a USB 2.0 Type-C cable with my own hub, it straight up refuses to work at all, but using a USB 3.2 Gen 2 cable or Thunderbolt 3 cable (same thing basically), it worked fine.

 

Thunderbolt 3 is easier to search for so I'm mainly trying that. I found a 2 meter (6.6ft) TB3 cable for $25. Though doing a mock-up with a 6.6ft charging cable I own, I've found that it's too short... Even a small room scale setup would make you tug your PC off the desk at that length, lol. So one would need to find a longer cable than that.

 

Though hey, if your basement happens to also be a Costco warehouse, apparently this cable exists: https://bhphotovideo.com/c/product/1522225-REG

i think the only viable solution at this time at least would be an optical powerbank with a powerbank strapped to your waist for power to the headset(as you mentioned previously)

unless of course youre able to find a normal cable of sufficient enough length to satisfy your demands

 

another option would be to link up multiple cables given that it doesn't increase latency exponentially

[Pecacheu]

After trying a number of different searches I've actually had some success searching for Oculus Quest Link Cables it seems. Here's one: https://amazon.com/dp/B085NNS16Y

 

This cable supports USB 3.2 10Gpbs and up to 60W power delivery. Theoretically it should work perfectly. The only strange thing is that there's no mention of any of these being active cables... Perhaps USB-C works differently and this length is possible without an active cable? Or maybe any hub it's connected to would provide signal boosting. Not sure. But the reviews seem to indicate it works, and not just for the Oculus Quest either, but for various other devices like connecting a phone to a MacBook, and it syncs data at full speed. That does sound like a good sign.

 

Btw if you didn't know, the Oculus Quest supports linking up to a PC as well as running in standalone mode... However from what I've heard the data that it sends over the cable is basically heavily compressed and travelling via only a single USB 3.0 link, not USB 3.1 w/ DisplayPort mode. Basically it's not utilizing the full potential of the USB-C connection, primarily for reverse compatibility reasons. (Basically, everyone get's a worse experience because not everyone's GPU/Desktop PC has a USB-C connector, some only have Type-A connectors.)