Parts 8, 9 & 10 have now been added, for those wishing to read them

Part 11 now here: http://www.wastedspace.co.uk/cms/2011/0 ... 93part-11/

Part 12 now here: http://www.wastedspace.co.uk/cms/2011/01/19/hmd-project-part-12/

This projecrt is now neatened up and is here: http://www.wastedspace.co.uk/cms/catego ... y-upgrade/



Hi, I have been lurking around here recently and thought some of you may be interested in my current project.

Although, when completed there will be a shiny blog entry, I thought I would start here and collect some feedback

Anyways; I decided I’d like to play with some 3D stuff and decided the best way to see 3D is with two video sources, immersively. Preferably with a tracker oh, and a wide field of view, obviously.

I was quite frankly shocked that HMD’s have pretty much remained in the 90’s! I decided that I didn’t want to pay 10,000+ for an hmd. Nor did I want to pay ~1500=>~3000 for something that would just about do the job.

So I did some research and decided that optics were key, so I managed to get an old VR4 headset with knackered electrics, but working optics from Tone over at http://www.vrtifacts.com/ for a very fair price – what a great guy.

All I had to do was find a way of replacing the old AMLCD’s with something more modern; I won’t bore you with the investigations here, that will be for the final report.

The old LCD’s are apparently 4:3 – 1.3 Inches. Although the HMD hasn’t arrived yet, I have finished my initial prototyping today.

What do you think?

http://www.wastedspace.co.uk/hmd/

Cool man. Love to see more DIY HMD projects. Are you using a pico-projector there in the pictures? How do you plan on mounting that?

Yup, it's a Samsung SP-HO3 - WVGA resolution, only, but the controller takes inputs upto SXGA which is very handy. It has to be said the picture is very very tidy. I may use SVGA pico's for the final thing - depending on how the tirals go.

I havn't actually got the helmet yet, but there is plentry of options for mounting, by the looks of things.

The idea is that I don't have to mess with the current LCD mounting points and optical alignment / calibration - as they are already perfect. Indeed, I want to create a mount which will then take the this years and future pico's 1080p and beyond.

So in this top down version of the prototype, the assembly would be screwed into the plastic frame which currently holds the LCD and the pico clamped into place looking down. Depending on how that goes, I am also toying with the idea of a dual mirror mount, so the pico's will actually lie flat, pointing away from one's forehead. we'll just have to see.

I have yet to finalise the projection material, it's be a grey acetate, most likely, but I need to wait for the HMD before seeing how things look for brightness and contrast. The beauty with projection is that you have full control over the image.

http://www.photonic-sourcing.com/public ... splays.pdf

I like these, but 180hz seems way too low for a microdisplay , I'd expect around 2000...

How so ? Isn't 60hz per colour good enough ?

For a HMD , yes, for a full fledged projector, no . BTW I have no idea if you can obtain these at all.

This projecrt is now neatened up and is here:

http://www.wastedspace.co.uk/cms/catego ... y-upgrade/

I am behind in the write-up - it's all good though

Wow, looks like good progress!

The end result will probably not be too cutting edge (Same as my V8), but the promise, as you say, is in the future.

It might be too expensive for you, but have you looked into laser based pico projectors? They have amazing colors and contrast, and can focus at any distance, no adjustment needed.

Looks very cool. I was also going to recommend a laser projector, like the Show WX.

Thanks
The little Samsungs are pretty darned good, I’m hoping the end result will be superior to any of the older displays – the quality of the image, from a geek point of view really is staggering. Even when the electronics are downscaling from SVGA or even XGA – it’s sharp, vibrant and very colourful – far better than any LCD I have seen, especially legacy stuff. I got my first home projector in 1999, which was a sharp VGA jobbie – 7K it was then. I’ve seen the same one, with a replacement spare panel and new bulb and…. Oh my god – what we used to put up with - I do believe that the Samsungs (and similar TI picos)’ VGA is better than single LED transmisive LCD counterparts. But I havn’t seen them, so it’s circumspect.
Although I think I’m onto a winner, the future of projection headmounts is just beginning ; Laser pico is very very exciting, it’s not that they are focus free – it’s beyond that – they are focusless! You should be able to pop those things ontop of yer head and have them shine onto a curved Perspex sheet 6 inches from your face, with a perfect all-round image… What we’ll need are LEEP style Oakleys to keep up
We’ll see. I’m enjoying it, and if this week goes well, I’ll enjoy New Vegas too

Thanks,

I meant to say in previous post - I did consider them - though not available here... yet - My primary concern was with my cuirrent rig design being rear projection... do I really want to be looing into laser light ? - No matter how diffued. Hell, I can't find a NORMAL diffuser that is good enough yet - let alone a laser light one !!

As I'll explain in later posts on my blog thing, re-engineering to be a fron projection headset is a major feat, really one worthy of a ground -up design.

Z

Nice job so far. I like to see the blog of this do-it-yourself stuff.
I was thinking that front projection could be better given the loss of colour and contrast when using aany diffuser for rear projection.
I think that the easiest may be if you have the projector pointing at a vertical mirror that rests against your forehead. Then have the lens on the projector offset down from the microdisplay in the projector.

Part 7 is now available: http://www.wastedspace.co.uk/cms/2010/1 ... ct-part-7/

Nice work. I also bought 2 pico's for my project but after some fiddling realized it would be difficult. The big demon is the screen material. Any rear projection material would be designed for large area but we are talking micro where the fiber or grain of the material is very visible being so close and under magnification. I do like the projectors facing down with a single mirror idea though.

Yeah, the material choice is a demon I am still fighting! I have some decent pro-film stuff, which isn't too bad, and I have just ordered a sample of this: http://www.prodisplay.com/black-rear-pr ... creen.html ...

If all else fails, I can always opt for front projection - there is room for a beamsplitter between the optics and the screen, though I would probably end up having to mount the projectors below the optics. We'll see!

Also, what on earth is a Revelator shitter ? - Sounds like a nasty toilet episode!

What about Vikuiti rear projection film?

Great work your doing

have you looked at this? http://www.vrtifacts.com/hmd's/leep-on-the-cheap the optics cost $25 per eye piece and can offer you nearly 90 degree diagonal field of view, which sounds amazing. I wonder if this would work well with your Samsung dual projector setup?

I am getting the impression it's all pretty much of a muchness, but having not tried any 3M badged stuff yet (Although I am sure some of the 'bespoke' stuff I have tried would be from 3M) I will order a little bit and give it a whirl.

What I have learned from this, is, there are a load of proper blaggers around, peddling cheap as chips perspex as 'super hires', 'HD', 'Infinite resolution' etc. It's nearly all the same cheap plastic... And I have heard some awful excuses for it not performing in a NTE (near to eye) application....

Indeed I have, Tone from that website has been a great help, and inspiration....

Optics-wise, I think there are bigger things on the horizon.... but one step at a time... I recently tried out the new VR1280 in which the optics, though superb, are starting to show their age.

Are the optics on the VR1280 any better than on the VR920? I noticed they made some improvements with the Wrap line, but the FOV is still pretty low. How did it look?

I think he means this: http://www.virtualresearch.com/products/vr1280.htm

^this

Ah, OK. Nevermind then. I was confusing this with the Vuzix VR1440.

Isnt that thing vaporware?

Yeah, probably. Thats why I was getting excited when I thought he tried it.

Vuzix is not a wizard of progress. They use off the shelf CyberDisplay modules made by Kopin, even the optics are from Kopin. All they really do is the driver board, and software, and the trivial job of making a shell (Which, as the VR920 shows, they cannot even effectively design a comfortable one).

Kopin does make 1280x800 modules, but they are extremely expensive. As such, Vuzix is not going to implement them.

Unlike the Vuzix you dismantled, the VR920 I got my hands on was simply one of these modules: http://www.kopin.com/data/Image/product ... oducts.jpg

So in this case, they didn't even do the driver board - and the two boards which make up this module have to be clasped together with an integrated interlink, so can't even easily remount or change IPD.

Are you sure it was that exact module? As far as I knew, there are two boards, one is the standard Kopin board that drives the panels, and the secondary board contains the motion tracking sensors and microphone interface.

I remounted my VR920 into a Fatshark Aviator with glass optics, 47 degree FOV. Too much distortion and blurring on the edges to be useful, and the new acrylic optics, while sharper, has some blue halo issues around the edges.

We should probably get back on topic, though!

Vuzix also supplies OLED headsets for the military, but I do not know who their supplier is.

Yup, deffo. I had the whole thing to bits to see if there was a way of using with the Virtual Research optics - but there was simply no way of magnifying the tiny display and maintaining decent exit pupil, I'll have pics up pretty soon.. It's all part of my retro upgrade project.

Parts 8, 9 & 10 have now been added, for those wishing to read them

http://www.wastedspace.co.uk/cms/2010/1 ... ct-part-8/
http://www.wastedspace.co.uk/cms/2010/1 ... ct-part-9/
http://www.wastedspace.co.uk/cms/2010/1 ... t-part-10/

(Don't expect any miracles!)

Thanks for sharing. Hopefully you continue your efforts with optics for the vr920 as well as lots of people would be interested in a solution.

Nice work man. I too wanted to upgrade the VR920's but I am not that good with hardware and wouldn't want to destroy my baby!

Could a small fresnel lens be used in front of the VR920 screens but behind the VR-4 optics.
I thought a fresnal lens worked a bit different than a regular magnification lens in that the light rays left it in parallel lines. So would using a fresnel lens not change the exit pupil like a regular magnification lens ?

The VR920 screens would be like an old small TV that people would put a fresnal lens in front of to make them bigger. Only in this case instead of you looking through the fresnel lens at a magnified small TV, it would be the VR-4 optics looking through the fresnel at the small VR920 screens magnified and then you looking through the VR-4 optics with their normal exit pupil.
You would want a very dense (I think number of grooves per inch) fresnel lens for a higher picture quality.
Fresnels do not produce a great picture but I was wondering is this sounded like it would work just to see how the VR920 screens would look with your VR-4 optics.

I do not know the quality of these lenses but they are small and I think with fresnels, you can cut them down smaller as long as you keep their center as the center.

They do say "hold 4inches away" which would be for the 2x magnification, but maybe you could find someway to make them work or some other fresnels to try .

http://www.altex.com/UltraOptix-Hi-Powe ... 41394.aspx

I do not know optics so this could be very, very wrong on all kinds of levels....
BUT hey, it's a $1.69...but maybe $20.00 S&H...LOL

It is my understanding that a Fresnel lens has essentially the same function as a regular lens. The purpose of the stepped rings is that it allows the lens to be much thinner than the equivalent lens if it were just smooth glass. I also suspect there are some other advantages, since the angle of approach for a ray is different, and this difference is exaggerated as you get to stronger powers.

While they are commonly used in projection systems when you need a large parallel beam of light, that purpose could also be done by a large, smooth lens. It would just be a big heavy lens.

Joe Dunfee

Hi Joe Dunfee,
I made a DIY projector with a pair of fresnels and what you say sound's right.

Do you have any idea how to enlarge those VR920 screens without it changing the original operating / functional spec's of the VR-4 optics ?

You basically can't.

Thank you PalmerTech for the reply.
When I saw I had typed "inlarge" not enlarge, I thought no one whould reply to me...LOL

I edited it out..Ha,Ha

If they gave a spelling test to get on the internet I would be banned for life.

I am really not a person who is very knowledgeable about optics, or even HMD's. I am just playing arm-chair quarterback here.

There is one optical thing I have always been curious about, Holographic optical elements [HOE]. Many years ago I recall reading that a hologram of a lens acts like a lens. But, I am not clear if the statement is true for just the other objects in the original hologram, or for any real-world object. If the first version is true, then a hologram of a prism would act like a prism.

Since a transmission hologram only works for a light source the exact same color as the laser originally used, we would make 3 exposures. One for each of the 3 primary colors. To correct for the color aberration in the prism, we simply shift the position of the prism for each color. It may also be possible to incorporate some magnification, but I think this would greatly complicate the process of creating the HOE. I know there are companies that specialize in this, but I have no idea of the cost involved.

When the HOE is used, the display is placed where the parabolic mirror was, and is back lit using LED's that are the same wavelength as the lasers originally used. Note that the hologram film would be transparent, so the display itself should be off to the side. This would allow for augmented reality if you don't block the view.

If anyone here has the money to burn for an experiment, there is a place, that sells a kit using self-developing holographic film. The laser is your basic laser-pointer type. The prices start at $99 for the kit, and the film itself is $40 for 10 2"x3" plates. Litiholo.com

As I think more about it, it sure would be easier to ask someone who knows holography better than I. Tell you what, I will do that and report back here.

Joe Dunfee

I have messed with holography myself, so I know what you are talking about. Unfortunately, a lens in a hologram only acts as a lens for objects in the original hologram. It would not be able to shift light from other sources like a real lens would, so your idea is a no go.

Holographic waveguides will happen, though. They basically move the focus of an image projected on them off into the distance. Great for AR.

Retinal displays will happen, too, but not on an immersive level for a long time. The exit pupil is just so absurdly small as to be useless with even the slightest bump or shift.