www.diycinema.co.uk

[Marticus]

ok now i does seem that i'm on my own here but at the very least this will serve as a place for me to compile my thoughts and get my project in order.
If anyone does read this Feel free to contribute

So My project aim is for a true 1080p HD Projector for under £500.

The Parts List:

In My possession:

LumenLab Pro Projection Triplet Lens 500mm fl
LumenLab Pro Fresnel Lenses 1 x 220mm and 1x 650mm (£100 in total)
PC Power Supply (£0)
Pc Case Fans (£0)
400Watt Metal Halide Lighting Kit from Doug (thankyou very much) (£20)
Bulb for aforementioned Kit.(£5.50)
FSMirror (£20)
15.4" WUXGA lcd panel (£25)

Parts to Purchase:

Parabolic Reflector (around £10)
Condenser Lens (unknown so far have yet to find a source)
330mm Fresnel Lens (Will replace the above 220mm) (around £20)
Controller Board for afore mentioned lcd panel (around £100)
Aluminium(not much)

Last edited by Marticus on Wed Dec 09, 2009 12:33 pm; edited 5 times in total

[Marticus]

OK so this is a VERY basic idea of how i plan on laying the projector out:


I am currently attempting to get my head around autocad in order to put together a working design.
Hopefully by the time i have aquired the rest of my parts i will have something to work from.

[doug]

Hi Marticus,

That should be a very impressive setup!

You might like google sketchup for the design. There's a short learning curve but once you get the hang of it you can produce scale drawings in no time and it's free.

Remember the 400W lamp produces nearly 400W of heat so if you jam it in the corner of a wooden case you might have problems keeping the wood cool enough to avoid it setting fire. It might also be worth getting some sort of UV filter for the lamp. I used some polycarbonate called 'palram palsun' (i think!) which had excellent transmission in the visible regime but rejected nearly all UV.

Remember there will be an optimum focus position where you have the most light focussed on the triplet. It's a good idea to optimise the position of the lenses based on the final position you plan to have the projector in or build in some mechanism for adjusting them.

Good luck with the project! The reflector/condenser system will probably be the biggest challenge but should make a substantial improvement to the brightness. Remember to go for a lamp with a reasonable colour temperature, from what i remember the lower ones (~5000k) give higher output in the visible spectrum.

I'll email you about the ballasts on the weekend.

Cheers,
Doug

[Marticus]

Hi doug,
Thanks for the tips.
I know of google sketchup as most of the guys on lumenlabs recomend it but i figuered that as i have access to autocad i may as well try to use it. However After an hour of messing around with autocad last night the little voice in my head said simply "your over complicating this" both in concept and action.
Sure i could spend the next few months becomin proficienbt in autocad but realisticly how often am i going to use it? never. and besides i wanna get this thing built goddamn it! . also as you pointed out, the key to the best results is ajustability not the most accurate design man can create.
So with that in mind i will be starting my design afresh and simplified on google sketchup.

I will be keeping it a folded design but i will be scrapping the verticle 45 degree angle design, the reason being i can already forsee what a nightmare it will be trying to reposition Fresnel lenses etc due to lack of space once the thing is put together.
The new design will be a horizontal fold similar to this:




I'm already dreading building the 'light engine' as they call it over the water but i figure i i try to keep everything ajustable i should be ok.
I plan to buid the lamp reflector and condenser into one unit that can be repositioned within the pj and i will have cool air directed over it to try and keep temperature sensible.

Thanks for the tip on the 'palram palsun' i will have to keep an eye out for some of that.

As far as the bulb goes i know on lumenlabs they say that 6500 k temp is the best you can find although how much that has to do with the fact that they sell those bulbs i dont know
The nearest i could find here was a double ended bulb with a 6500k temp for about £60 which i a little above what i wanted to spend on a bulb and i didn't know if the ballasts you have could run a double ended bulb (or if it made any difference atall for that matter)

thanks for all the suggestions.
If you (or anyone else who reads this for that matter) know of any places in the uk i might be able to source some of the remaining parts on my list at a reasonable price please let me know as currently i am looking at buying a lot of it from the us/eu which means high delivery and customs charges etc...

[Marticus]

Ok quick update.

scored a fs mirror from ebay from a photo copier i think? looks to be good quality it's VERY thick and mounted on a sheet of steel/aluminium.

also got some condenser lenses that i am experimenting with. not sure whether they will be suitable due to the focal length but i will have a shot.

i have also found a supplier in china for Pixelworks controller boards at a considerable saving over the prices of american/european stores. i didn;t order anything yet so dont know about the quality / service but from what i have seen they are legit and can supply quickly.

i have been considering building out of sheet aluminium due to the fact that the weight of the components i have is already adding up. not sure how this will behave with the heat from the bulb though?

anyway next on the list is the bulb so that i can start experimenting with the condenser lenses etc...

[Marticus]

ok small update. just scored these from ebay.


for £20 !!!!!

and delivery...

so one more thing from the list. i still need to find a reflector and some more suitable condenser lenses. not having much luck finding a uk source for these bits but patience has served me will so far so i will keep looking.

[doug]

That's a great deal on the lamps! I think i paid the same for just one. Hopefully the colour temp. isn't too high. Mine was 9300k so i had a lot of UV light in lieu of visible, although it was still reasonable.

I spent a long time trying to find a reflector. I remember some people were using hemi spherical metal bowls for food or something..probably the best bet if you want something large and cheap although i never actually found one!

[Marticus]

I beleive the lamps are 5800k so they should be good. if a little on the yellow side.

I know some of the US guys used a bowl from IKEA. unfortunately it doesn't look like theyre selling them anymore. also i think if i want to use a condenser lense i will need something with a similar diameter?

anyway the projects on hold right now as money's short and i'm planning a move to poland shortly. but i will keep looking and when things get started again i will post up progress.

[Marticus]

ok another quick update..

patience is indeed serving me well.. i just got hold of a 15.4" WUXGA screen for £25 i love ebay!

it had a faulty backlight but thats not a problem..

its a samsung model LTN154U2 so it should do the trick nicely... next i just need the controller boardf which i can order as i know which screen it needs to be programmed for.. and then i am pretty much ready to start the build..

that probably wont happen for a while anyhow as i am insanely busy right now...