spherical dome made out of satellite dishes

[PeterP]

After moving to a greater flat I have now a little room (12sqm) that I want to use for a new gaming rig. The heart of the visualisation is planed to look similar like this:

 

I already know that I need the minimum of two 16:9 fullHD projectors (better three 4:3 for more pixels) and a image warping software like nthusim

(http://forums.eagle.ru/showthread.php?t=56006).

 

I want to build the projection-screen out of several overlapping satellite dishes of 90cm in diameter So that after cutting them at the top and bottom I will have 70cm of vertical projection space left.

Than I want to body-filler the overlapping and paint to get a even surface.

MY first question :

I tried to sketch plan how many dishes and room I will need for this project but its really hard to calculate the screen an the projection without a CAD tool.

I'm a total noob in using CAD programs :) (I never did before).

So can someone recommend me a simple free-ware CAD drawing program where I can simulate this project and also export my data later to a more advanced program when I'm more experienced ?

 

Thanks for your advises in advance!

 

I will post updates when the project will left the planning-phase.

 

EDIT: http://forums.eagle.ru/showthread.php?p=1000107#post1000107

Small update:

 

Got all my Dishes (8 for 100€!) and cut already the border from one of them away with the angel-grinder.

(The middle one is without the border - 1mm thick 92cm high and 80cm wide)

 

 

I also made new plans that match the size of the dishes I have:

 

 

Here I have taped everything roughly together to get a feeling for the final size...

 

 

This is getting Huge!

 

 

 

:D

overllapping dishes.bmp

Edited October 13, 2010 by PeterP

[CoNa]

For a free CAD software, try Google Sketchup which is free and quite easy to use. There is a lot of "how to" on youtube and other sites.

Also, there is a huge library of 3d object to download. So no need to draw everything . I used it to make my simpit.

 

[G3]

great idea and good luck,

those sat dishes would make for a hell of a wrap around screen.

can't wait to see your results, sim visual heaven i would imagine.

[PeterP]

Thanks for the Tip, CoNa!

Google Sketchup has everything on-board what I need for my planning and it is astonishing easy to use! (but I have to say that I have plenty of Adobe-Illustrator time behind me and vectors are not absolute new to me -I needed roughly 5 hours for the pictures below + one hour research )

 

I started with seven 90cm dishes and added them together like this:

I think this can be easily done by riveting after I have cut the thicker border of the dishes away.

 

Than I will have to cut everything in shape. I plan to use a laser marker to do the markings for this work.

 

190° and 74 cm high.

 

 

I also simulated the projection with data I got from a website about projectors. Throw Ratio:1,5-2,2 Aspect ratio 16:9

It looks to be no big problem to come along with only two projectors.

 

 

On the picture below you can see that I will have sufficient room above my head to wear a hat tracker and that I will not touch the projection cone , even If I will lean forward :). The projectors are also mounted high enough that they will not disturb a Tracking cam that is pointing at me.

 

Everything looks that It could really be possible made without the need of too much work and money...

7 dishes ~ 250€

2 projectors ~ 700€

Filler and paint, sand paper ~ 100€

Minor things like some tools and parts for the stand for the dome ~ 100€

----------------------------------

roughly 1200€ + some time

 

 

Now I only have to do It for real! I visited already some ebayshops of people selling new 90cm dishes for 30-45 €. But before I go this way I will look at some local junkyards and merchants for TV equipment for used ones that will be sufficient for my needs.

 

My time-line is to spend the season holidays with DCS-A10 together with this setup. (and a brand new HOTAS Warthog is also on that list )

 

My never before used angel grinder is already jumping up and down in pleasant anticipation !!!

Edited September 3, 2010 by PeterP

[m0jo]

 

This setup might have some focus issus with the projector because the lenght between the lens and the surface seem quite different for some points(top/bottom and side/center).

[Avilator]

There may also be issues with keystone effect as well. This results from the projector not being perpendicular to the surface that it is projecting on. In your design, they are pointing at quite a large angle down, and this may cause an issue.

[deadsmell]

Interesting.

 

Im curious though, why use the satellite dishes as opposed to more conventional building materials?

[hassata]

I'm liking that gal

[JLZ]

Looks like a good idea :)

 

Maybe you can find workshop where they make tin roofs. They should have tools for making shapes from tin just like you want for your project.

[BHawthorne]

There may also be issues with keystone effect as well. This results from the projector not being perpendicular to the surface that it is projecting on. In your design, they are pointing at quite a large angle down, and this may cause an issue.

 

NTHUSIM Plus is capable of advanced keystoning to correct not just the edge geometry, but every part of the projection on both projectors, so that'll not be an issue.

 

There might be some focus area issues where some parts of the projection are softer than others. With short throw projectors though (0.5-0.6:1 lens throw) they don't really have that extreme of a mounting angle. The projectors will be for the most part point ahead toward the screen and are mounted about a foot above the top of the screen edge. The short throw lens design is desinged to throw down at short distances at a simular kind of location -- just not so extreme a downward angle.

 

The mathematics of all of that can be worked out by using Projector Calculator Pro at Projector Central's website.

 

I use the current NTHUSIM Plus build with DCS: Black Shark and DCS: LOMAC 2.0 and am a forum moderator over at the NTHUSIM site, so feel free to ask me anything and I'll do my best to help out. I even have a YouTube video of the DCS engine working on my YouTube channel (BHawthorne72).

 

My suggestion would be to only buy one of the dishes and make a fiberglass reverse mold of the original part. Take that and layup the entire screen curve in segments but it can still be a continuous fiberglass part -- it'll just take laying up an area, then popping it off the waxed mold surface and continuing with the layup after about 12 hours of cure time per area. Theoretically you could do a full 360 degree layup off that single dish if you did it in enough layup times.

 

Fiberglass composites layup is not hard at all. You just need some wax for release on the mold, enough room temperature cure resin and fiberglass cloth to achieve the layup. I also recommend a $100 vacuum pump with hoses and a port with bagging material, so the resin flow through the material is consistant. But with it being a reverse mold -- you can do without the vacuum pump if you really want to cut budget, but you have to be more mindfull of air pockets in the layup. That might be more sanding and bondo repair to the final part, but either way you could do it a lot cheaper and more consistant than segmented cut together dishes.

 

Either way looks like a very plausiable idea. :thumbup:

Edited September 5, 2010 by BHawthorne

[PeterP]

Thanks all for your feedback!

 

This setup might have some focus issue with the projector because the length between the lens and the surface seem quite different for some points(top/bottom and side/center).

 

I had also great concerns about the offset of the focus in the first place , but I made a lot of research in the last days and I learned about "lens shifting" and like BHawthorne also mentioned: "NTHUSIM Plus is capable of advanced keystoning to correct not just the edge geometry, but every part of the projection on both projectors, so that'll not be an issue."

 

But that means that I was a little optimistic about the price for a projector in the first place. A projector with the specs that I need will cost more than 300€.

I need a a minimum throw of 1:2, lens-shifting capabilities of 40° vertical.

I'm still searching for a model with a affordable price.

There is also a "plan B" - there is also the posibility to give the projektors "glasses" and make a DIY lens shift.

Anyway - I will run some tests the with a projector of a friend the next weeks.

 

But before I will buy the projectors I need the projection surface.

 

 

And here comes the good News: I went yesterday in small obscure Asian electronic shop where you can get everything- you know, starting with electronical driven chopsticks (?!) to military grade NVgoggles...:music_whistling:.

 

The owner is selling also one aluminium SAT-Dish (90x100cm) that looked perfect for my projekt.

So I asked for the price and he answered:

70€... - than I told him that I only need the dish without the mounting or other parts ...-

30€ - Than I told him that I need seven of them.

He went in the back of his shop made a phone-call.

2min later He came back and said that that when I will pay him 10€ ahead I can collect my seven dishes for 100€ in ten days. - OK, -Deal!:)

 

Thanks also for the advisees about doing it with fiberglas or asking in a workshop.

But my conclusion is that you can't beat the price of 100€ by doing it in a other way. The Dish is made out of aluminium,very sturdy, the shape is already there and I have to fill only the triangles between the segments instead of making a form and so on.

 

@BHawthorne

I will doubtless join the discussion in the NTHUSIM forum when I'm at the point to bring the different pieces together. I really appreciate your presences in this tread! I followed your thread in the FighteropsForum.

Really inspiring!

 

BHawthorne's Setup:

Edited September 5, 2010 by PeterP

[PeterP]

Small update:

 

Got all my Dishes (8 for 100€!) and cut already the border from one of them away with the angel-grinder.

(The middle one is without the border - 1mm thick 92cm high and 80cm wide)

 

 

I also made new plans that match the size of the dishes I have:

 

 

Here I have taped everything roughly together to get a feeling for the final size...

 

 

This is getting Huge!

 

 

 

:D

Edited October 13, 2010 by PeterP

[CyBerkut]

The only problem with those illustrations is that the woman is not slapping the crap out of you for cluttering up her home!!! ;)

 

Seriously though, it's a very interesting project. :thumbup: Good luck with it!

[Jg2001_Rasputin]

PeterP sind die Schüsseln als Unterkonstruktion gedacht, oder soll darauf das Bild projeziert werden? Mit einer dünnen Sperrholzplatte (2-3mm, lässt sich super biegen) hättest du so eine Biegung auch locker hinbekommen.

[PeterP]

PeterP sind die Schьsseln als Unterkonstruktion gedacht, oder soll darauf das Bild projeziert werden? Mit einer dьnnen Sperrholzplatte (2-3mm, lдsst sich super biegen) hдttest du so eine Biegung auch locker hinbekommen.

 

Rasputin, please post English in a English forum or use the PM function instead!

 

Translation:

"Are the dishes meant as the final projection surface or are they a auxiliary construction for the final surface.

With a thin sheet of plywood (2-3mm) you would be able to get a same curve easily."

 

Yes this should be the final surface (after filled and painted).

Please view the video in post 1 for reference.

What you are advising is a cylindrical projection surface.

On a cylind.proj. you have a noticeable offset-angle of your view at the top and bottom regions.

The advantage of a spherical surface is that you have everywhere the same distance to you view/eye-point and you looking every time straight on it.

You have also a much more natural picture (if you made a good correction -> nthusim).

A cylindrical projection will be always a little distorted from your point of view at the top and bottom -not much- but you can notice.

 

Anyway, thanks for your suggestion!

Spherical vs. Cylindrical projection surface:

Edited October 16, 2010 by PeterP

[Scudslaker]

verry interesting...but most important for me is, how you get a curved display signal on the screen..is there a cheap solution,..you told of some lenses? how much will they cost!)

 

to get those satellite dishes is easy, we build and sell them apart to our LCD devices up to 46" and settop boxes..

so my offer for other interested builders, to get them cheap!) contact me!)

 

cheers

SCUD

cheers and

[PeterP]

verry interesting...but most important for me is, how you get a curved display signal on the screen..is there a cheap solution,..you told of some lenses? how much will they cost!)

http://nthusim.com/

[diveplane]

The only problem with those illustrations is that the woman is not slapping the crap out of you for cluttering up her home!!! ;)

 

Seriously though, it's a very interesting project. :thumbup: Good luck with it!

 

lmao nice one

[Scudslaker]

thx,..nice again)

[Feed]

Would it not be easier to cut vertical edges (left/right) and join the dishes edge-to-edge? You could use the scraps across the top and bottom edges to help align the curvature, and reduce your putty/filler work. Just a thought.

[Scudslaker]

as i understood, that was his plan!) he just fixed together to get first impression of real dimension.

[Feed]

It looks like to me the plan was to cut them horizontally across the top and bottom, but that the left and right edges would all overlap, requiring rather significant areas be filled in and smoothed out. I'm suggesting instead to make vertical cuts so that the left and right edges of each dish is a line, and butt them edge-to edge, using the cut off sides as stiffeners on the backside of the top and bottom edges. Either way, it's a fantastic idea, and I look forward to seeing how it turns out!

[PeterP]

Here is a little update (that by fact is no update at all...):

 

@Feed

You are correct -

Up to now is everything cut and hold by rivets together... the triangles between the dishes are filled with 1mm thick plastic sheets to have a absolute even surface ...

 

But this project did get on hold...

 

but I wasn't really passive:

A picture Tale: "Dual Thrust" or "What I did in my Easter Holiday"

 

Two MS FFB2 with Cougar Grip

 

...life changed a little and my "man-cave" turned into a nursery in the meantime...:)...

and the cost's for the needed projectors would break my neck right now.

So all the dishes and wishes are abandoned into the cellar for a uncertain time...:smilewink:

 

 

I'll come back...!

Edited January 24, 2012 by PeterP