Extending the walking range of the Rift (making cables long)

HDMI sucks! :P

It's electrically identical to DVI, which is otherwise much superior. DVI cables up to 25 meters long are sold. Without any attenuation I use a 10 meter DVI cable at 1920x1200, 60Hz for 'silencing' my PC by keeping it in another room. (Who uses optical media these days anyway??)

DVI is much more affordable than HDMI and generally of much higher quality.

Hi Ganzuul,

Are you using your 10 meter DVI cable with a RIFT?

We're got various setups using 15 meter cables from desktops to projectors, using both HDMI and DVI and they work fine (unfortunately the cables are tied / locked down so I can't actually connect a rift into them). Also, one of the laptops I'm using only has an HDMI output (no DVI - and I'm trying to avoid using a HDMI to DVI adaptor).

No, not to the Rift but to my monitor. 1920x1200 has the same aspect ratio as the DK1, so I usually leave the resolution high, duplicate the display, and let the Rift's box downscale.

I don't have any position translation gear set up, but I could do the USB power hack and run a long USB cable too....


Just had a thought: Have you tried putting the laptop in a backpack which you hang from the back support of a spinny chair? It could be an interesting movement paradigm.

Nice idea about the backpack. We looked into this for some augmented glasses we were playing with, but we're suspending the user and unfortunately the backpack was a little too heavy and affected their motion.

I bought a non-name power adapter that had a longer cable and fried the control box as a result so I wouldn't suggest this route :)

I think its pretty much null now with the release of DK2 without a control box, but if anyone is interested I have looked into this and can tell you:

1. Extending the cable between the HMD and control box is impractical, only because cables with the correct configuration of cores, thin & light enough to be comparable with the original, are not available anywhere I could find. Bear in mind, this isn't just a 20-core cable, this is a 20-core cable with sets of differential pairs that must run at 1GHz/1.25GHz+ or the like. Others must carry large amounts of power, and others that operate at whatever frequency the USB data lines operate at. Electrically, its no problem to spec out, practically buying it as a hobbyist or even a small company however...

2. Yes you can extend the power cable between the adapter to the control box. However. The Rift takes 0.6A and at that level the voltage drop over the cable becomes a real problem, and if the cable is too long and the conductors are too small, the Rift will start to power on, then brownout and shut down. I have bought some 0.75mm2 speaker cable with a resistance of <0.05Ω/m which for 10 meters should result in a small enough voltage drop that the Rift should still power on, and so far it works OK.

3. I also prefer DVI to HDMI in general. For this though, while they both use current-mode logic, HDMI specifies a higher frequency per channel than DVI, which allows an HDMI 1.4 cable with four differential pairs (i.e. a thinner cable) to drive a 4K display. DVI would require dual-link for these resolutions (that is, 6 data pairs and a clock pair, making it thicker). HDMI also supports Ethernet and audio in the cable which could be utilised to reduce the number of cables on the Rift further.

I've been told DK2 won't work well with extenders. You need to use the cables that come with it.

"cybereality" wrote:
I've been told DK2 won't work well with extenders. You need to use the cables that come with it.

Disappointing.

I would of thought that using mini displayport would be better due to the higher bandwidth compared to hdmi or am I wrong

DisplayPort would be better I think as well, especially over HDMI since DP is royalty-free. I would guess that HDMI has been chosen because it is far more common than DisplayPort though.

There is no reason the DK2 wouldn't work with longer cables, provided they were active. That is, they actively boost & 'repair' the signals, with a device such as this: https://www.youtube.com/watch?v=ArgEecfK6TE
You can get HDMI cables now with these kind of line drivers in them.

For power, you'd need to transmit at a higher voltage (e.g. 12-24v) then step-down just before the Rift. The higher voltage means lower current, and therefore lower voltage drop, allowing for longer and thinner cables. A DC-DC converter such as a buck converter at the end can step-down to 5v very efficiently. You can get them for ~£5 off eBay. (This one works fine with the DK1: http://www.ebay.co.uk/itm/7V-24V-to-5V-3A-DC-DC-Step-Down-Converter-Buck-Module-with-USB-Output-KIS3R33S-/281216550302)