Oculus Rift - Slip Ring Ideas

Alkapwn
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Oculus Rift - Slip Ring Ideas

Post by Alkapwn »

Hey everyone. I know there's still a lot of discussion yet to be had about what the best way to use the Rift is. And which controller would be best suited, and stuff like that. One thing I'd like to get started on is for those of use that will be attempting to use the Rift in a full 360º environment. Meaning standing or sitting with the ability to completely turn around 360º.

There's been talks here and there about slip rings. Now that we know the "final" specs of the developer kit, I wanted to see if we could get the masses looking into a possible best solution for use with the Rift. I believe it's been stated that the cable running from the headset to the control box cannot be extended without degrading quality. If the cable has a decent length to begin with, a ceiling mounted control box with custom slip ring for the custom cable could work out nicely. Leaving the ability to get longer cables from the box to the comp/wall for power.

I've personally e-mailed these guys, http://www.slipring.com/capsule.htm as I've stated before, to see what can be done by way of a custom slip ring, with a potential bulk order to be placed with fellow forum members.

If anyone else has some ideas as what might work the best, companies, ebay, etc. I say we start compiling them now, That way we can get the best possible solution ready in time for when the Rift arrives.
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Re: Oculus Rift - Slip Ring Ideas

Post by cybereality »

I will probably be using the Rift either in a stationary seated position, or with a backtop. However, if you do need to order as a group, I will throw down some money for this.
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Re: Oculus Rift - Slip Ring Ideas

Post by Krenzo »

Alkapwn wrote:I believe it's been stated that the cable running from the headset to the control box cannot be extended without degrading quality.
I'm not sure I buy that. Differential signaling (which USB and HDMI signals use) is very resilient to cable attenuation. I could maybe see a problem if they're sending 5V over the cable, and there are components in the Rift that absolutely need 5V. I'm currently sending 5V over 50ft of Cat 7 ethernet cable for my position tracking system, and it drops 1V over the length arriving at the other side as 4V. This wouldn't be a problem if the Rift uses 3.3V or lower.
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Re: Oculus Rift - Slip Ring Ideas

Post by PalmerTech »

Krenzo wrote:
Alkapwn wrote:I believe it's been stated that the cable running from the headset to the control box cannot be extended without degrading quality.
I'm not sure I buy that. Differential signaling (which USB and HDMI signals use) is very resilient to cable attenuation. I could maybe see a problem if they're sending 5V over the cable, and there are components in the Rift that absolutely need 5V. I'm currently sending 5V over 50ft of Cat 7 ethernet cable for my position tracking system, and it drops 1V over the length arriving at the other side as 4V. This wouldn't be a problem if the Rift uses 3.3V or lower.
It is not HDMI that is being sent over our custom cable, it is LVDS. In addition to that, we are running USB, the LCD backlight power, and a few other lines. On top of that, the cabling uses extremely thin wire, which certainly does not help the problem.
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Re: Oculus Rift - Slip Ring Ideas

Post by 2EyeGuy »

So a slip ring is something that allows a cable to rotate on it's axis as much as you want? That would be good if mounted on the ceiling, although I still want to be able to crouch (maybe even lie prone) or jump.
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Re: Oculus Rift - Slip Ring Ideas

Post by 2EyeGuy »

PalmerTech wrote:It is not HDMI that is being sent over our custom cable, it is LVDS. In addition to that, we are running USB, the LCD backlight power, and a few other lines. On top of that, the cabling uses extremely thin wire, which certainly does not help the problem.
So why are you using extremely thin wire then? Is it just because it needs to be flexible?
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Re: Oculus Rift - Slip Ring Ideas

Post by alekki »

As I said in another thread, I'm definitely interested. You would have to mail the thing to Europe for me, though.
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Re: Oculus Rift - Slip Ring Ideas

Post by crespo80 »

alekki wrote:As I said in another thread, I'm definitely interested. You would have to mail the thing to Europe for me, though.
Me too (Italy) as long as the price is fair
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Re: Oculus Rift - Slip Ring Ideas

Post by Okta »

My guess is...not a chance in hell :lol:
Dont splip rings use some type of brush system? ON a video signal? Thats gonna look sweeeeeeeeet.
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Re: Oculus Rift - Slip Ring Ideas

Post by Krenzo »

PalmerTech wrote:It is not HDMI that is being sent over our custom cable, it is LVDS. In addition to that, we are running USB, the LCD backlight power, and a few other lines. On top of that, the cabling uses extremely thin wire, which certainly does not help the problem.
Ok, but LVDS is still differential signaling just like HDMI. I can understand attenuation being bad if you're using very thin wire. Can you say what voltage is being sent through the wire?
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Re: Oculus Rift - Slip Ring Ideas

Post by alpha »

I don't think*1 DVI will work through a slip ring setup... but if you want to find out I would at least suggest not to invest to much money and only order one as a proof of concept first.

*1 at least non of the slip rings manufactures I looked at listed DVI or HDMI in one of there application suggestions.
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Re: Oculus Rift - Slip Ring Ideas

Post by PalmerTech »

2EyeGuy wrote:
PalmerTech wrote:It is not HDMI that is being sent over our custom cable, it is LVDS. In addition to that, we are running USB, the LCD backlight power, and a few other lines. On top of that, the cabling uses extremely thin wire, which certainly does not help the problem.
So why are you using extremely thin wire then? Is it just because it needs to be flexible?
There are a lot of lines to run, and the cable needs to be lightweight and flexible. The cable could be extended a bit more, but it makes more sense to wear the control box on your belt and just use a long HDMI cable.
Krenzo wrote:
PalmerTech wrote:It is not HDMI that is being sent over our custom cable, it is LVDS. In addition to that, we are running USB, the LCD backlight power, and a few other lines. On top of that, the cabling uses extremely thin wire, which certainly does not help the problem.
Ok, but LVDS is still differential signaling just like HDMI. I can understand attenuation being bad if you're using very thin wire. Can you say what voltage is being sent through the wire?
The two highest voltages we have are 5v and 12v. A lot of power to be running through such a thin cable.
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Re: Oculus Rift - Slip Ring Ideas

Post by Metathias »

PalmerTech wrote: The two highest voltages we have are 5v and 12v. A lot of power to be running through such a thin cable.
Agreed does this concern you at all? Cables are the bane of my existence. And i hope i dont do to the oculus what i do to all my headphones.
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Re: Oculus Rift - Slip Ring Ideas

Post by Alkapwn »

PalmerTech wrote:The two highest voltages we have are 5v and 12v. A lot of power to be running through such a thin cable.
So the USB at 5v, power cable at 12v and then the HDMI. Anything special about the HDMI data rate?

Also does anyone know if we can just use a regular slip ring and just match the wires up? Is that doable without the need to get a custom one built?
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Re: Oculus Rift - Slip Ring Ideas

Post by brantlew »

PalmerTech wrote:There are a lot of lines to run, and the cable needs to be lightweight and flexible. The cable could be extended a bit more, but it makes more sense to wear the control box on your belt and just use a long HDMI cable.
Here's an idea. Go ahead and sculpt a belt clip on the box enclosure mold. Also, pretty please ensure that the connectors are really tight on the control box. The ST1080 has horrible connectors that slide out super easy and make mobile VR a real pain. And one last thing. Please think hard about the best placement for the connectors on the control box. It seems that you guys have initially done connectors in the front and back which is ok for desk usage - but that's not always convenient for mobile usage. Often you want to shove the control box in a pocket which is difficult if it's got wires coming out opposite ends. Also, if you had a slip ring and a belt mounted control box, the optimal placement might be to have both input and output connectors on the same side - facing up. Or maybe on front and side instead of front and back...
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Re: Oculus Rift - Slip Ring Ideas

Post by Nick3DvB »

Alkapwn wrote:Also does anyone know if we can just use a regular slip ring and just match the wires up? Is that doable without the need to get a custom one built?
I remember looking into this a few months back, was going to get one of these to play around with:

http://www.ebay.com/sch/i.html?_sacat=0 ... 24&_sop=15

I had trouble finding english data sheets for them, we really need to know the physical track order so we can alternate the signal pairs inside the capsule (as well a twist / shielding the fly leads). I think I'll just order some and have a go at this after Christmas, I know you can send LVDS through some CCTV designs so will try that first, but we might have more luck on the HDMI side, we could try splicing the slip-ring into an active cable, but I imagine the signalling is pretty finely balanced in those things? I want to try and squeeze stereo audio down there to but shielding might be a problem, it would be good to know if the new custom driver board can do PCM/AC3 audio over HDMI? I think a belt mount on the break-out box is a very good idea, just wear it on your back and run the slip line down to that intsead, you don't really want dead-weight hanging off the HMD anyway.
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Re: Oculus Rift - Slip Ring Ideas

Post by PalmerTech »

Metathias wrote:
PalmerTech wrote: The two highest voltages we have are 5v and 12v. A lot of power to be running through such a thin cable.
Agreed does this concern you at all? Cables are the bane of my existence. And i hope i dont do to the oculus what i do to all my headphones.
It did during the design process, but not anymore. We worked with the factory to make sure this cable is extremely durable, and extensive length testing was performed.
Alkapwn wrote:
PalmerTech wrote:The two highest voltages we have are 5v and 12v. A lot of power to be running through such a thin cable.
So the USB at 5v, power cable at 12v and then the HDMI. Anything special about the HDMI data rate?

Also does anyone know if we can just use a regular slip ring and just match the wires up? Is that doable without the need to get a custom one built?
LVDS, not HDMI. Nothing particularly special about it. A regular slip ring would work as well as a custom one, I think. The question is, can LVDS survive through that kind of connector?
brantlew wrote:
PalmerTech wrote:There are a lot of lines to run, and the cable needs to be lightweight and flexible. The cable could be extended a bit more, but it makes more sense to wear the control box on your belt and just use a long HDMI cable.
Here's an idea. Go ahead and sculpt a belt clip on the box enclosure mold. Also, pretty please ensure that the connectors are really tight on the control box. The ST1080 has horrible connectors that slide out super easy and make mobile VR a real pain. And one last thing. Please think hard about the best placement for the connectors on the control box. It seems that you guys have initially done connectors in the front and back which is ok for desk usage - but that's not always convenient for mobile usage. Often you want to shove the control box in a pocket which is difficult if it's got wires coming out opposite ends. Also, if you had a slip ring and a belt mounted control box, the optimal placement might be to have both input and output connectors on the same side - facing up. Or maybe on front and side instead of front and back...
It is too late to change the control box at this point, tooling is already under way. We considered a belt clip, but at this point, there are a minuscule number of people who would actually use it. I would get a clip like this one, it has an easy to attach adhesive nub, and is the strongest swiveling belt clip I have used: http://www.theclip.com/store/product.ph ... 277&page=1

The connections between the control box and the headset are hardwired like the Z800, so you definitely don't have to worry about them coming out! :P We could have had connectors, but it was a challenge finding a balance between low enough tear away force and high enough clipping power, so we pushed all that R&D forward to the consumer unit. I agree that having connectors on either side is not optimal for mobile usage, but I made the call to make something that worked best for the average seated user. My reasoning was that if a user is smart enough to be putting together a backtop or mobile device based rig, they would not have too much of a problem making the cables work. Maybe I will design a 3D printable external shell for the control box with a belt clip and cable management and release the files?
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Re: Oculus Rift - Slip Ring Ideas

Post by Alkapwn »

PalmerTech wrote:LVDS, not HDMI. Nothing particularly special about it. A regular slip ring would work as well as a custom one, I think. The question is, can LVDS survive through that kind of connector?
Is there an ability to get extra cables for experimentation? In looking online, it looks as if it could be possible. How many pins would be needed for the cable? If you're allowed to say at this point.
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Re: Oculus Rift - Slip Ring Ideas

Post by PalmerTech »

I will get extra cables to whoever needs them.
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Re: Oculus Rift - Slip Ring Ideas

Post by Dycus »

Nick3DvB wrote:
Alkapwn wrote:Also does anyone know if we can just use a regular slip ring and just match the wires up? Is that doable without the need to get a custom one built?
I remember looking into this a few months back, was going to get one of these to play around with:

http://www.ebay.com/sch/i.html?_sacat=0 ... 24&_sop=15

I had trouble finding english data sheets for them, we really need to know the physical track order so we can alternate the signal pairs inside the capsule (as well a twist / shielding the fly leads).
From my experimentation, LVDS isn't that fragile. I'm running it successfully over a 6ft HDMI cable (that even has incorrect impedance), with rather messy, non-twisted wiring at the connector ends. The key is just to keep them short, the wires coming out of the connectors aren't longer than 1.5 inches.

I'm willing to bet you could get LVDS, USB, and stereo audio over a 24-pin slipring just fine.
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Re: Oculus Rift - Slip Ring Ideas

Post by Alkapwn »

PalmerTech wrote:I will get extra cables to whoever needs them.
Palmer, you da man! I'll def be down for an extra cable when you get around to implementing the pre-Kickstarter orders.

Thanks again for dedication and effort you're putting into this! And for how helpful and responsive you've been with the whole community here.
Dycus wrote:
Nick3DvB wrote:
Alkapwn wrote:Also does anyone know if we can just use a regular slip ring and just match the wires up? Is that doable without the need to get a custom one built?
I remember looking into this a few months back, was going to get one of these to play around with:

http://www.ebay.com/sch/i.html?_sacat=0 ... 24&_sop=15

I had trouble finding english data sheets for them, we really need to know the physical track order so we can alternate the signal pairs inside the capsule (as well a twist / shielding the fly leads).
From my experimentation, LVDS isn't that fragile. I'm running it successfully over a 6ft HDMI cable (that even has incorrect impedance), with rather messy, non-twisted wiring at the connector ends. The key is just to keep them short, the wires coming out of the connectors aren't longer than 1.5 inches.

I'm willing to bet you could get LVDS, USB, and stereo audio over a 24-pin slipring just fine.
Sweet deal Dycus! You rock also! I will be picking up a slip ring for sure then.

I think Palmer, that you had mentioned wearing the control box and just using a longer HDMI cable? Wouldn't you also need to run the USB and power cables from the control box to the comp and wall? I'm assuming it'd be easier to just put the slipring in the middle of the custom cable.
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Re: Oculus Rift - Slip Ring Ideas

Post by Nick3DvB »

I'm pretty sure LVDS would be ok for relatively short cables, but some people are going to want much longer cable runs, assuming the slip-ring is on a ceiling mount along with the break-out box and they still want to be able to walk around / crouch etc (or if they have a high ceiling). I guess we're already way out of spec on the LVDS side so when you factor in a longer cable then any additional noise introduced by the slip-ring might be a killer. But if we wear the break-out box instead we should be able to use much longer cables, at ~720p we are well within HDMI spec (in terms of bandwidth) so that should leave a lot more scope for SNR changes, I'm hoping the same is true for USB, but we could always use a micro hub to amp that back up if needs be, and that might allow for additional low current USB peripherals to.
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Re: Oculus Rift - Slip Ring Ideas

Post by Krenzo »

Dycus wrote:6ft HDMI cable (that even has incorrect impedance)
I thought the HDMI spec defined the cable impedance. How could you find one with incorrect impedance?
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Re: Oculus Rift - Slip Ring Ideas

Post by Nick3DvB »

The combi cable sends LVDS (and USB) over a TDMS (HDMI) cable.
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Re: Oculus Rift - Slip Ring Ideas

Post by Dycus »

Nick3DvB wrote:I guess we're already way out of spec on the LVDS side so when you factor in a longer cable then any additional noise introduced by the slip-ring might be a killer.
Yes, this is true. Once in a while, LVDS won't work right over a 6ft HDMI cable and I have to use a 4ft one instead. I'd count on having to put the slipring very close above your head.
Krenzo wrote:
Dycus wrote:6ft HDMI cable (that even has incorrect impedance)
I thought the HDMI spec defined the cable impedance. How could you find one with incorrect impedance?
Correct for HDMI, incorrect for LVDS. At least, I think. Isn't HDMI 100Ω, while LVDS is 80Ω? Or maybe it's the other way around? Or maybe they're actually the same. Truthfully, I'm not sure. Hmm.

Well, anyway, if you're making a LVDS/USB combo cable from an HDMI cable, make sure you don't use one over 6ft. HDMI cables longer than that are always active cables, and won't work. You need a passive cable.
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Re: Oculus Rift - Slip Ring Ideas

Post by Nick3DvB »

I'm not sure about the impedance either, but I'm guessing the panel has other things to worry about at these sort of distances! :lol:

Good call on the fabric cable btw, I was starting to think about something like that, most of the really thin HDMI cables seem to be active to,

StarTech do a cheap 3.5mm passive one but its not very flexible: http://uk.startech.com/Cables/Audio-Vid ... HDMIACMM6S

I'm going to make up some custom cables but I can only find fabric "lamp" cable online, so I'm looking for a supplier that does standard ~3mm rubber cable off the reel, any ideas?
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Re: Oculus Rift - Slip Ring Ideas

Post by Krenzo »

Dycus wrote:Correct for HDMI, incorrect for LVDS. At least, I think. Isn't HDMI 100Ω, while LVDS is 80Ω? Or maybe it's the other way around? Or maybe they're actually the same. Truthfully, I'm not sure. Hmm.
LVDS is 100Ω. All differential signaling I've seen (CML, PECL, LVPECL, LVDS) has been 100Ω.
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Re: Oculus Rift - Slip Ring Ideas

Post by Dycus »

Ah, all right then. So, correct impedance, but the signal just starts degrading too much at further lengths.
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Re: Oculus Rift - Slip Ring Ideas

Post by Alkapwn »

Crap, I think I'm getting confused now with all the cable talk. Is the custom cable that's coming with the Rift an actual HDMI cable? Or is it a custom cable resembling the same characteristics of an HDMI cable?

So...
           custom cable                            /-----USB-----
RIFT-----SLIPRING-----CONTROL BOX |-----HDMI-----
                                                          \----POWER---

As apposed to
              custom cable                    /-----USB------\                  /-----USB-----
RIFT-------------------CONTROL BOX |-----HDMI------|SLIPRING|-----HDMI-----
                                                      \----POWER----/                \----POWER----
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Re: Oculus Rift - Slip Ring Ideas

Post by Dycus »

Between the headset and the control box is our custom cable that carries LVDS and USB. The control box will have some kind of video input, USB, and power.

If you're using a slipring, I'd put it between the headset and control box. This may not be the best idea, however. Plus, you'll be cutting up your Rift's cable.
It's probably better to have the control box with you, and put power, USB, and HDMI/DVI over the slipring instead.
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Re: Oculus Rift - Slip Ring Ideas

Post by Nick3DvB »

Sorry for confusing things, if you're going to be seated or standing on the spot then you should be ok just cutting the Rift cable (if you can bring yourself to do it!), but you'll be soldering about the same number of joins either way. Just bear in mind that the LVDS is already at it's limit so if you have lots of EMI flying around (from WiFi, Bluetooth / wireless headphones, Xbox pad, Hydra etc) you might need to add some more shielding around connections or the capsule itself, but that's why god gave us foil tape! :lol:
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Re: Oculus Rift - Slip Ring Ideas

Post by Alkapwn »

Nick3DvB wrote:Sorry for confusing things, if you're going to be seated or standing on the spot then you should be ok just cutting the Rift cable (if you can bring yourself to do it!), but you'll be soldering about the same number of joins either way. Just bear in mind that the LVDS is already at it's limit so if you have lots of EMI flying around (from WiFi, Bluetooth / wireless headphones, Xbox pad, Hydra etc) you might need to add some more shielding around connections or the capsule itself, but that's why god gave us foil tape! :lol:
Luckily for us, Palmer is super awesome!
PalmerTech wrote:I will get extra cables to whoever needs them.
I guess we'll just have to factor in the pros and cons of each method. I personally plan on demoing this to every gamer that I know. So still gotta figure out what the best way to do that is gonna be. I'm thinking maybe a mic stand with a boom that I can setup over their heads with the slipring there. Should make it more portable without sacrificing functionality. Will just have to do some weight testing and stuff. Good news is Monoprice has some.
http://www.monoprice.com/products/produ ... largeimage
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Re: Oculus Rift - Slip Ring Ideas

Post by Direlight »

Interesting topic, found a "traditional" swivel method. Maybe it's mechanism is similar to slip rings?

http://www.mtbs3d.com/phpBB/viewtopic.p ... 89#p100589

Slip rings seem like they could work as long as they don't strip the insulation off or something. Never seen one.
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Re: Oculus Rift - Slip Ring Ideas

Post by elliottmyers »

Hi - I realise this is an old thread...but just found it!

Check out this link and let me know what you think...
http://youtu.be/s4XottjkHzQ

Hope you like it - please do comment!

Elliott
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Re: Oculus Rift - Slip Ring Ideas

Post by Nick3DvB »

Hey Elliott, just noticed your reply, good to see you found MTBS at last! It’s a bit quiet around here these days...
Shame you didn’t drop by 2 years ago, would have liked to get your take on my crazy GameTrak idea! :P

There must have been quite a few GameTrak owners on here, I did a few tracking experiments with it myself

but I ended-up using a modified retractable cable for my slip-ring setup:

Image Image Image Image Image

I finally got around to building it, about this time last year actually, but didn't get time to post a proper DIY guide so

I’ve just chucked some photos of the build up on imgur for anyone who's still interested: http://imgur.com/a/BWXPf

Your Roto VR system looks great! Good luck with the KickStarter, nice to see you’re getting some press now, I’m plugging it whenever I can for you.
Good call moving the PC off the base, hard disks don’t like pulling too many G’s, and I prefer my water-cooling loop neither shaken nor stirred! :lol:

I really hope you get some traction on the Oculus SDK integration stuff, to compensate for the camera rotation issue etc, I’m not a software guy but it should be possible to hack a shim in there somehow if it comes to it. Maybe OSVR or Sixense’s new SDK could present a possible solution at some point, it will be interesting to see how all the input API stuff pans-out in the long run.

Personally I’ve been hooked on standing VR and fully-decoupled controls for a while now, after trying Teddy’s excellent Hydra-deck demos I could never go back to “gun-face” VR. In fact I couldn’t really play much else on DK1, even cock-pit stuff without positional tracking was a problem after 20 minutes, and I’m still waiting to miraculously develop immunity to stick-yaw turning, I'm not holding my breath. I ended-up modding HydraCoverShooter to work with some old UDK maps and just spent a few days exploring them! Even when calibrated properly, Hydra positional-tracking obviously isn’t a patch on DK2, but I still think the intuitive control scheme (360 degree, fully de-coupled) makes those early HydraDeck demos some of the most immersive publicly available VR demos - to this day.

I still remember the first time I got the calibration dialled-in just right, I had been playing HydraCoverShooter for about 10 minutes when I accidently dropped my Hydra controller, I looked down to see it’s virtual representation lying on the ground behind me, and (without even thinking about) just crouched down, picked it up, then turned to aim at something and carried on playing. A few seconds later it struck me – I was actually *in* VR… I know I experienced my first fleeting moments of presence in that demo, so I just want to say thank you Teddy0k – I’ll never forget it. HL2VR used to be amazing to, but sadly its Hydra torso-tracking mode has been broken for a long time now, hopefully Nathan will get around to fixing that with the STEM update (was nagging them about it on Reddit but didn't get very far).

(@Cybereality - It’s a real shame they've pulled the plug on UDK… :cry:

It would be nice to try these demos in the DK2, any chance of releasing that internal build some day?

After the recent UE4 announcement I'm not sure what harm Epic thinks it could do now??)

I think most people have been really under-estimating the importance of proprioception in general, just look at the response to the standing Oculus Connect and (Re)Vive Lighthouse demos, this aspect of presence seems to have come as a revelation to many. Even when seated, adding inertial cues into the mix will be really compelling for certain content.

@Elliott - How are you getting on with the Roto’s new slip-ring design? The quotes I was getting for custom wired units had a few too many zeros on the end, so I just built one myself for less than £50! There are still some cheap Moog capsules left on eBay if you’re quick, but the Chinese clones should work ok at low rpm. It would be interesting to compare notes on the electrical performance; I pushed mine to 1920x1200@75Hz without any visible pixel artefacts. I’ve not actually tested it with DK2 yet, been really busy lately so lent it to a friend and he’s taking his time getting it back to me. But I’ve already made up some break-out adapters to send power, USB & sync down standard HDMI cable, and I’m hoping voltage-drop won’t be as much of an issue for DK2. I added a simple EEPROM circuit to spoof some signals on the PC side of the slip-ring, I was expecting detection issues anyway and needed another pair free because I’d originally planned to try and send the two Hydra controllers signals over the slip-ring to, but I chickened-out of that in the end, didn’t want to risk it after the Hydra supply dried-up and the price gouging started, might still try it some day though.

If it wasn’t for the sync signal I could have used a cheaper 12 track slip-ring, if you are keeping the camera on the Roto’s base you could probably get away with that, by EDID cloning and tying all the shields to a common ground etc. When I get time I’m going to make up some DisplayPort adapters to see how far I can push the bandwidth on my prototype. The HDMI repeater isn’t actually needed for most short cables, and to be any use on the other side of the slip-ring it would need some manual re-tuning via it’s SMbus, not played with any of that yet though, something like the RedMere chip would probably be better for CV1 anyway. Not sure if Oculus will use DisplayPort or HDMI 2.0 for CV1, dual-link DVI seems very unlikely, but who knows, they could go with ThunderBolt, SuperMHL or something really weird I’ve not thought of?

http://www.feelthree.com/2015/03/ultra- ... layport-2/

Longer term we might end up having to use something like a 12G-SDI coax or optical hybrid slip-ring to get the bandwidth, but that would be expensive and signal conversion might add some latency. If nothing turns-up on the wireless front maybe these magic light-bulbs could be the solution one day!

http://www.tweaktown.com/news/43630/res ... index.html

Wireless is not really a pre-requisite for standing VR anyway, back-top PCs are one solution, but those retractable cables actually work pretty well over a small area, just don’t stray too far off your “magic carpet”. Because it’s a ribbon cable it actually helps drive the slip-ring around as it retracts, but they are not very robust and I think they’ll struggle electrically with CV1 (very thin cores, no proper shielding etc). There are better retractable cables out there but a custom design would probably be needed, short coiled “phone cord” type HDMI cables would work ok for ODTs but they stretch easily and are a bugger to untangle.

I found that you really need a thicker cable to transfer enough torque to get the slip-ring moving, very thin cables just want to loop-up like you see in all the Omni / Virtualizer videos. I’ve been thinking about a way to use a longer very thin cable by integrating the retractor spool & slip-ring together, putting the slip-ring at the centre of a lightly-sprung spool and mounting it to the ceiling as one unit, turned on it’s side and maybe angled down towards the player on some sort of rotating gimbal mount. Unfortunately that would be the easy part…

The cable to body interface remains the biggest problem, as Palmer suggested I normally fixed the DK1 box to a belt-clip on my back, this worked ok but you really need it higher-up, walking backwards is unnatural and turning around quickly onto the extended cable was still an issue sometimes. But you don’t want the cable going directly onto the HMD either, the weight / tension tries to pull it off - and no one wants to wear a chin strap! For safe head-clearance you really need at least a foot of rigid stand-off fixed high up on your back, centred between the shoulders probably makes the most sense. I looked at camera poll-mounts but they are really cumbersome, you probably want something like this or a H.A.N.S harness but with a much taller "collar" structure to run the cable down onto (lightly tensioned to take up any slack). It's obviously not ideal but it solves most of the safety and comfort issues without adding too much complexity. I suppose you could try and integrate it into a tracker-mount harness of some kind, but it’s not exactly practical, let alone productizable.

Sorry for the brain-dump but I’ve been meaning to post about this for a while now. It’s great to see someone else working on the locomotion problem has actually gone and built something! I've always loved a good contraption (apparently that word has a negative connotation!?) - didn't John Carmack tweet something recently about "a prototype being worth a thousand meetings…” ? I have to agree, I think your final design is looking great.

Hopefully once the various tracking solutions finally start to roll-out we’ll see more demos with fully de-coupled control schemes. Then you just need to find your killer-app for the motorised view-point stuff, a great turret-shooter maybe or some cool 360 video experiences should do the trick, I guess you've already reached out to the big flight-sim / space-shooter developers? (DCS, Elite: Dangerous, Star Citizen, EVE: Valkyrie, DarkField VR and so on)

Valve’s Lighthouse tracking seems to have got people thinking about standing VR again, maybe that could actually be a thing, but I guess we knew that all along really…

I say damn the lawyers Oculus – you’ve got to stand up for your rights sometimes!

After all, accidents will happen, even whilst sitting down: http://www.theregister.co.uk/2015/03/05 ... o_trouble/

Be careful with those trade-show demos Elliott! ;)

Will keep an eye on http://www.rotovr.com

Best of luck with the KickStarter launch - “build it and they will come...” 8-)

https://www.kickstarter.com/projects/ro ... next-level
geekmaster
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Re: Oculus Rift - Slip Ring Ideas

Post by geekmaster »

I just noticed the RotoVR in my email, with a notification from kickstarter. It makes me want to continue my experiments with my work in progress (but I was using wireless HDMI instead of slip-rings):

http://www.mtbs3d.com/phpBB/viewtopic.p ... 77#p129177
Gametrak
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Re: Oculus Rift - Slip Ring Ideas

Post by Gametrak »

Hi guys - just saw this thread - looks like we've created a solution that fits this thread exactly!

https://www.kickstarter.com/projects/ro ... =discovery

Slip rings with video signals do work!

Is this thread still active?

Elliott @ Roto
Gametrak
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Re: Oculus Rift - Slip Ring Ideas

Post by Gametrak »

Hey Nick!

Wow - only just saw your message. I'm rather in awe. Thanks so much for your support and delighted you know about Gametrak too!

If you build it...not many people coming yet...

https://www.kickstarter.com/projects/ro ... =discovery

Slip rings on DK2 work a treat btw.

You still here?

Elliott @ Roto
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Re: Oculus Rift - Slip Ring Ideas

Post by Nick3DvB »

Is there anybody there… :? This is starting to feel a bit like a séance… Ghosts of MTBS3D past. :lol:

No I wouldn’t call this thread active exactly, it just felt like the right place dump that lot the other day.

Thanks Elliott, I thought you might appreciate it, big fan of your work btw, the GameTrak has inspired me and many others.

I was also really disappointed by the slow up-take, but not entirely surprised; many solid projects have struggled with KickStarter fatigue recently. I have sent a few people in your direction, but I’m not a social-media user so not sure how much help I can be on the marketing front. There is definitely some price sensitivity, but it’s probably just bad timing more than anything, the Vive announcement probably didn’t help matters. But its early days, three weeks is a long time in VR, I’m sure you can still pull this back! Just a few ideas, for what they’re worth…

I know you don’t want to position the Roto exclusively as a sim-chair, but it can’t hurt to aggressively target that market to ! At the current price-point they seem like your most natural customers to me, a valuable first-wave at least. Why not start engaging on the flight / motor racing sim forums:

http://forums.eagle.ru/showthread.php?t=93477&page=374
http://forum.wmdportal.com/showthread.p ... iscussion/

Many of these guys are only just discovering VR, then go on to try other experiences and get hooked. You give them more flexibility than a specific sim-chair, and you win hands down on style – the “wife approval factor” etc. Let them help spread the word about the additional VR benefits later down the line, but do what’s necessary to get funded first! I would emphasise the motor / inertial cues aspect specifically for the vehicle based games (and video experiences). I know you want to simplify the marketing message but still take care not to conflate separate issues / features.

Given the price-point issue, maybe approach some corporate types about promotions / installations. I’d talk to Jonathan Tustain and the Inition guys about that kind of thing,
and I’m sure Kevin Williams (KWP, DNA etc) will have some thoughts on out-of-home applications, he suggested you talk to Samsung directly about GearVR launch demos – that’s certainly worth a shot.

For 360 movies, the director having view-override is a valuable feature in the long term, but something like a POV car chase experience would be a great primer for public demos. You could record real orientation data in car but even “faking it” with existing footage would be pretty compelling. Maybe ask Peter Wimmer about implementing the motor playback, or you could just hijack the subtitle system?


Lastly, I think pitching the de-coupled controls / foot-plate navigation feature is going to be the really tricky part at the moment, given that all the input / navigation stuff is still up in the air - this is uncharted territory for everyone right now. Many won’t appreciate the value of fully de-coupling head & body control because they just haven’t had the chance to try it, in fact it could be argued that most typical Rift + Game-Pad users haven’t truly experienced VR yet ! (by most reasonable definitions) Anchoring the body’s physical orientation into the virtual space is fundamentally important - whether you are seated or standing. It solves the un-intuitive control-scheme issues at a stroke, the fact it also cures motion sickness for most people is just an added bonus IMO.

It was interesting to see a back-lash developing against Vive and standing VR, the floor space and exertion arguments could help you, but there are strong arguments on both sides. The Reddit hordes seem to have defaulted back to Oculus-bashing again now, but it remains a divisive issue. Eventually people will realise that there’s no right answer here – we all perceive the world differently so it’s going to come down to personal preference in the end. 1:1 tracking purists will only ever want to sit IRL when they are sitting in VR, but for everyone else the Roto still looks like the best of both worlds to me ! I will have a think about some de-coupled control demo ideas for you, the Mech shooters seem like another good fit, but having some non-vehicle based examples would be of more value.

(btw - Is the yaw shaft-encoder stuff implemented yet? as part of a HID ?? )

Great to see R2VR have got a piece up finally, and the GadgetShowLive gig should be a massive boost – things are looking up ! :D

Just let me know if there’s anything else I can do to help. 8-)



@Geekmaster – seems like great minds think alike after all, what's your take on all this then?

Those bargain LG boxes look great btw – do they play nice at 75hz on DK2, what’s the latency like?
Gametrak
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Re: Oculus Rift - Slip Ring Ideas

Post by Gametrak »

Thanks Nick - talk about finger on the pulse. Lots of meat for us to chew on - have circulated with the team and think you should join us:)

Will jump on your suggestions and get back to you with an update. Thanks so much .

Btw: re Kevin Williams...do you know him?
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