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  #581 (permalink)  
Old 28th June, 2006, 06:34 PM
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haha
I have been thinking about cutting a hole in the large lense and fitting the smaller one in as well
Its possible it can help but I will need to place the bulb inside it to get the focal point of the smaller reflector. This means cutting it up but tools are cheap these days so shouldnt cost a lot to do.
There are likely to be issues due to mismatch of efficiency and the different angles of reflection could produce light banding effects.

If I had a way of making live adjustments to more than just the height of the light bulb I would be able to experiment more. Each time any other adjustment is made I have to turn it off, wait for it to cool, do the adjustment, wait a bit longer for the bulb to cool to its strike temperature then power it up again. It needs a good 10 mins for the bulb to cool. I've read that attempting to turn it on when not ready shortens the life of the bulb so its wise to wait a bit longer. Each time you turn on a MH bulb its life decreases a tad (supposedly), I dont know in which regard though, so I'm cautious about turning it off/on a lot.

If I was to try the above mod, I would like to be able to raise/lower the outer reflector while the projector is running. I'd also like to be able to bend it to alter the angle of reflection as I'm sure it will be needed to match in light banding effects better.
Its probably not the easiest of mods to setup well.

Standard projector theory suggests that only light that reflects back onto the LCD directly through the lamp light ball should be considered useful. Anything outside that is waste. (ie the light the outside reflector sends back wont be of use)
Maybe this is true, I cannot prove either way but I have learnt that the fresnel lense can forward more light than just that which is focussed on it. So maybe when using the condensor lense to bring the light angle even further inline this mod could have some benefit.

Brilliant! you have a good friend there
Be sure to tell him exactly what you need, dont miss a thing as its easy to use a favour up if you arent happy with what he gets!

I tested the light delivery without the condensor lense a long time back and had to read every page to find it. That was hard as I didnt know what the lense was called then!
This post was just after I got the new MH bulb and I compared with/without the condensor:
http://www.aoaforums.com/forum/299051-post234.html
(last bit of the 3rd paragraph, starts with the word "Initially")

It seems to help create a more even spread of light over the screen, making the centre/edge difference less.
I will do this test again soon to see if it affects overall brightness as well.
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  #582 (permalink)  
Old 28th June, 2006, 07:53 PM
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Well!
removing the condensor lense makes quite a big difference.
The centre/edge light difference isnt huge but overall the screen is way darker. White looks grey now!
I certainly recommend getting one.

Right I'm putting it back how it was, this is naff
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  #583 (permalink)  
Old 28th June, 2006, 08:05 PM
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Quote:
Originally Posted by Chernobyl
Heres the last picture with the condensor lense in place.
I wish to revise my 70 to 80% brightness figure as it isnt as bad as I first thought. It is about 80 to 90% of the brightness of the proper reflector once the bulb has fully warmed up.

I'm back on the original reflector and it is definitely better.
I am impressed with the Ikea reflector though, I expected far more problems like uneven light distribution and a colour tint. It could also get somewhere near the brightness of the proper reflector if set up correctly.

For the sake of 9 Euros + post, I feel it is worth getting the proper reflector rather than this if you have a small bulb like the HQI-TS

Some time soon I want to get the ladle reflector which surrounds the bulb from the shop in the US.
Darth Vader must have had a weapon that looked like that!
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  #584 (permalink)  
Old 28th June, 2006, 10:05 PM
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lol
shall we call that reflector the Deathstar

on a completely random note, this is funny
http://www.zeblong.com/breakfasttransformer/
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  #585 (permalink)  
Old 28th June, 2006, 10:14 PM
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They are getting VERY good at these things!
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  #586 (permalink)  
Old 2nd July, 2006, 07:48 PM
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hey there,


sorry for the late reply, been ultra busy at work etc.

i have actually started work on the projector covering now, starting to look pretty good. looks alot like ET when he is in the bmx - the pictures will do the talking. still dont have my camera cable so they will have to wait though(sorry) There will be no way to tell if the cover is succesful until i get all the other parts of the build...


Still waiting on news of the free lighting kit. hope it comes, so i can order my fresnel etc from the german guy. he hasnt actually replied to my email yet - doesnt fill me with confidence!!

thanks for doing the condenser test, i will defo be getting one now. althought the german site is currently out of stock so i may have to wait, or source it from somewhere else.
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  #587 (permalink)  
Old 3rd July, 2006, 04:17 PM
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Phewee its too hot to work on the projector!
I've been watching Tennis instead, Maria Sharapova

I did a bit of research to see if anyone else with the same monitor as me has tried peeling off the antiglare layer and surprisingly enough, someone has.
Sadly he doesnt rate the process for my LCD as he lost 2 pixels and can hardly tell the difference after.
http://www.diyaudio.com/forums/showt...?postid=771109

One thing I have learnt through researching this is that which side the Antiglare layer is on can have a big difference (and that some antiglare layers are more transmissive than others).
ie those who make a projector box which project straight from LCD>Lenses>screen have the LCD with the antiglare layer facing the bulb.
Those who use a mirror (OHP users etc) before the picture hits the screen have the antiglare layer facing towards the screen not the bulb.
When the AntiGlare layer faces the bulb, more of the light is reflected back and/or refracted so light losses are greater. A stroke of good fortune there for us OHP users.

On the other hand, the gains to be had from stripping the AntiGlare layer are much less for us so the question is (especially for my LCD)...
Is it worth the risk??

If there was a better screen out there that I wanted to buy (if I broke this one), I would be tempted but as things stand, I cant get what I want yet as the LCDs are either too big or too low res. I dont mind spending money getting better parts but dont want to if theres no improvement.

This brings me onto the research I'm doing for a higher res projector.
I've searched far and wide for a 17" LCD that will do 1600x1200 + and they simply dont exist! Its not easy to find a 19" LCD that will do 1600x1200 either but at least they do exist.
This is a bit of a bind and I dont see the situation improving as there is no general consumer demand for the parts I want.
This means the minimum size LCD I have to use is a 19" for the next generation projector. This also means I need a 19" fresnel which I have seen for sale somewhere. As the light spread will need to cover a 19" fresnel (vs a 15" fresnel), the light assembly needs to be further away from the fresnel adding to the height of the projector.
(I am still going to use a mirror before the picture hits the screen otherwise the projector would be placed on its side and the projector length would be increased instead)
This isnt a problem as I already have the projector raised off the floor

Once I have all the parts, I want to make sure the best use of them is made. This isnt as easy as one might like as practically everything will need to be moveable/tuneable.
ie the back reflector position, the condensor lense, the light assembly, the front and rear fresnels, the LCD, the top (triplet) lense and mirror all need to be able to move not just closer/further away but need to have some movement for a full 360 degrees to line things up perfectly.

Its true that using theory and perfect parts/implementation you can design the perfect setup on paper but rarely is anything perfect so trial and error will be needed anyway. The ability to be able to adjust everything while the projector is in use will be invaluable and will reduce the setup time drastically as well as getting absolutely spot on results.
Its not going to be easy to make everything moveable so I'm on the lookout for simple sliding mechanisms that can be used.

I've selected a piece of furniture I have here to build the new projector inside. Its from IKEA but they dont sell them any more and indeed nothing they sell now is of the same quality or the correct size for the job.
This is unfortunate as I hoped to make the project easily reproducible. It wont be hard to make a box so it shouldnt be a real problem.

Dan, I'm looking forward to seeing your piccies and especially want to know the effect a condensor lense has for you.
You'll need to find a way to mount it. If you get stuck, check my previous pictures of it and perhaps build something similar without blocking too much of the lense.

The German guy seems like a cowboy outfit but he himself is professional and does want to get things right.
If he doesnt get back to you, try again. I know he is away sometimes as other people have responded instead of him. Maybe he cant get the staff It looks like he does this part time or after work.

Good luck getting your free bulb
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Last edited by Chernobyl; 3rd July, 2006 at 04:21 PM.
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  #588 (permalink)  
Old 3rd July, 2006, 05:04 PM
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I have noticed the same issue with LCD displays and resolutions that you have (1600x1200 in 17" is virtually impossible to find). However, many of the higher-end laptops are coming with 1600x1200 in 14" displays, so it IS possible, TECHNICALLY. Perhaps you should try sourcing a panel from a laptop?

Last edited by Gizmo; 3rd July, 2006 at 05:05 PM.
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  #589 (permalink)  
Old 3rd July, 2006, 05:40 PM
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yes I forgot to mention that.
The laptop panels come in a wonderful array of resolutions in smaller sizes and could be ideal.
If the screens came with the driving electronics allowing vga input I would probably do it but most of the driving circuits interface directly to laptop motherboards or are on the laptop motherboard and arent any use sadly.

As the LCDs dont come with the driving electronics I would have to source it myself. This means I need to know what panels I can get circuits for and will be restricted to only using those.
The panel and driving circuit will also need a decent power supply (maybe a PC PSU will be good enough?).

I havent heard of anyone getting a projector running using this method yet.
From what I have seen so far the cheapest LCD driver circuit alone costs upwards of £200 and none I've seen so far have a VGA input
I'm keeping my eye out for more info.
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  #590 (permalink)  
Old 3rd July, 2006, 08:11 PM
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hmm it seems I'm not entirely correct as someone has used a laptop panel to create a 1080p projector.
He started off with an LCD monitor and replaced it with this panel later.
http://www.lumenlab.com/forums/index.php?showtopic=7962
a faq on the panel used:
http://members.cox.net/minoten/faq.shtml

I am discouraged by the specs of the panel, its 25mS and doesnt display true colour, only 256,000 colours!
Normally one is a trade off for the other although users of the panel dont have a problem with ghosting so maybe it is fast enough?
He seems to like it but I dont feel I have to restrict the project specs in this fashion.

ps I'm not sure I would go as high res as 1080p capable until my computer can run games at that res.
LCDs dont look as good when not running at their default res.
I'd prefer to get 1600x1200 for now
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Last edited by Chernobyl; 3rd July, 2006 at 08:14 PM.
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  #591 (permalink)  
Old 4th July, 2006, 12:07 AM
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ok, you did it!
I'm looking at using a laptop lcd panel for the project now.

Its going to take some time to gather all the info needed in order to select decent panels. I will need to find a supplier who either already makes or is prepared to make a VGA and/or HDMI interface for the panel.
There isnt any point in going for less than 1080p screen size (unless all the panels are slow or low on colours) as its what I'll want in a year or 2 anyway. I'd better start saving for a next gen gfx card!
The ground is just warming up for projects like this so in time more components should become readily available.

I have found something interesting...
They guy who did a bulk purchase of the panels/controllers has tried or has got info on Samsung panels. apparently they suffer from the burn in I get. It appears that not all LCDs suffer this (or dont suffer it at the temps I have).
Another consideration for the new panel.

There arent a lot of panel manufacturers in the world, many different brand LCDs use the same panels. I'll find out which manufacturers panels suffer the problem and if it is just certain panels rather than an issue with all of them.
The panel controller they used initially for the 1080p projector had problems with displaying 480p, it came out green. I am still reading about it but as far as I have read, the controller manufacturer has issued a bios upgrade that will make 480p work along with all other HDTV resolutions but disables all other resolutions like standard PC ones. Newer controllers wont have the issue and will display all resolutions.
I dont like the idea of spending a lot (they spent $715) and getting a faulty/beta product which the manufacturer isnt prepared to replace.
I also dont intend on spending anything near $715

There are a number of pretty cheap panels available on Ebay that I can use for trying things out.
I'll start researching the controllers, what they are capable of and how much they cost.
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  #592 (permalink)  
Old 10th July, 2006, 01:04 PM
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I have found a very suitable controller for the project that is capable of handling a wide variety of panels. The specifications for it are superb.

I called the UK side of the company who were very courteous and took an interest in the project. I have asked if there is anything they can do with the price given the exposure they will get here, hopefully this is something they would like to be part of.

I have seen US price quotes at $250 for 1000 parts and $475 (£250) for a single evaluation unit. We fall into the evaluation category sadly.
I'm hopeful we can get a price which will allow myself and our readers to make their own HD projector with this board

The companys website is www.digitalview.com
The controller is the SVH-1920, the full specs and user manual can be downloaded here
http://www.digitalview.com/controllers/products.php

The controller is perfect (it really is) and has a mean time before failure of over 10 years (permanent use)!
The only misgiving is it doesnt appear to support 720p (1280x720 - 16:9) res. This may be a none issue though, as the larger res of 1280x1024 (4:3) is. It does support 1280x768 too.
My worry is that 720p from sources other than the PC will be stretched to full screen. The difference isnt great at 1280x768 anyway so maybe it wouldnt be noticable if that res is used.

I'll investigate further.

I'm very hopeful

(Edited to make corrections)
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Last edited by Chernobyl; 10th July, 2006 at 02:12 PM.
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  #593 (permalink)  
Old 10th July, 2006, 01:21 PM
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I finally got around to making my first projector after a couple years of collecting bits, this thread has given me a boost and answered tons of questions I might have been asking all over the web.

Projector as it is now consists of:
Dukane 3010 OHP
800 x 600 12" LCD (from some mall kiosk or something)
my old HTPC
a shower curtain on the basement wall
Attached Thumbnails
Home made projector!-80in-image.jpg  
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Old 10th July, 2006, 01:55 PM
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lol brilliant and a result too!
Nice to have you with us ChurchSubgenius.

I'm glad this thread has been helpful.
Please let us know of any parts of the project that needed some thinking to get past or if it just bolted together.

How is the shower curtain? Have you had a chance to compare it to any other screens?
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Last edited by Chernobyl; 10th July, 2006 at 02:14 PM.
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Old 10th July, 2006, 02:25 PM
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I have no real comparisons to the shower curtain, it's better than my tan panelling walls .
I will get a pic of the rig this week and post it. I still need to create a shroud over the LCD to the lens and cut out more of the light bleed from the OHP body (prob use the ol' cardboard box method) before I will get maximum contrast on the screen.
I am thinking that a rolling cabinet (like the old school stereo cabinet) is going to be my best bet so I have started looking on Craigslist and garage sales (I am in U.S., do you have Craigslist in U.K.?)
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Old 10th July, 2006, 03:10 PM
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its funny you asked that, I was preparing to put up a picture of the new projector base I am building into.
I got it from IKEA a few years ago for about £35 and sadly you cant get them any more.
Its on wheels and is almost exactly the right height to lay the LCD on for a 3 metre screen.

Here it is with a damaged 15" LCD on top to show the size.
It should be just big enough to take a 19" 1080 capable LCD if the laptop panel method proves too costly.

With my setup here. the shroud doesnt make a big difference to the contrast ratio as I have dark walls. It is really annoying to have the uncovered projector in the corner of your eye while using it though.
I imagine with light colour walls it will help tremendously to have one as you say.

I hadnt heard of Craigslist before today and bizarrely you are the second to mention it. There are quite a few areas over here using it now, thanks for the headsup.

Please do post any more pics.
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Old 11th July, 2006, 03:41 AM
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good news!!

Great news!!!

i have a metal halide light and kit!!!

its a phillips HPI-T PLUS 250watt light complete with ballast rig. the ballast is (thankfully) quite silent. wired it all up tonight and it works fine, thought at first the light was terrible!! but after about 30 seconds it fired up to a tremendous level!!

The bulb and fittings are HUGE - the bulb length is 25cms!!! AAAh, i dont think it will be too much of a problem though as i can fit it in the projector diagonaly.

i cant believe the difference in the light colour, its quite remarkable. i had it on in the projector and it makes the room light up bright white! awesome stuff. you can really see the difference when you turn my desk lamp back on and it a horrible YELLOW colour... euch.

doesnt seem to be nearly as much heat coming out of it as the previous old skool lamp i had in the projector before.

ooh chernobyl - what do you think of these condenser lenses?

http://cgi.ebay.co.uk/2-x-Gnome-Opti...ayphotohosting

so all i need now, is a condenser lens, a new fresnel and some uv filter material!! and the dream of a full screen will be realised!

Dan
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Old 11th July, 2006, 02:21 PM
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hey well done!
I tried to look up your light and think I have found it on Philips INCREDIBLY slow site!
http://www.prismaecat.lighting.philips.com/LightSite/Whirlwind.aspx?eca=LEPPLG&cpf=GBEPEN&stg=ACT&lan=E N&cnt_key=DHPITP%20%20+|PHL|871150017989015+++&ecu =LMP|PHL|EP&t=3&tree=0&scr_md=1111&leftnav=2_1&nav =Null&loc=Null
Can you let me know if this is the one. It has a colour code of 65 which means 4500K colour which is a bit below ideal but if you are happy with it, thats all that matters
There isnt any info to say how long it will last but I imagine it will be at least 6,000 hours going up to 20,000 hours.
Light power is just short of 21,000 lumens which is the same as my bulb.

Another useful bit of info...
at the bottom of this INCREDIBLY slow page they highlight that the bulb can be used with different electronics which will vary the colour and brightness.
http://www.prismaecat.lighting.philips.com/LightSite/Whirlwind.aspx?eca=LEPPLG&cpf=GBEREN&stg=ACT&lan=E N+&ecu=LMP|PHL|EP&cnt_key=DHPITP%20%20+|PHL&t=1&tr ee=0&scr_md=1111&nav=Null&loc=Null&leftnav=2_1
To save you the trouble, here is the text:
"System

* Can be run on HPI-gear as well as on SON-gear ("Plus"-concept). The results in both light output and colour temperature are different"

Who knows what the actual differences are, if yours looks good to you, keep it as it is lol
Hopefully the bulb is small enough to line it up properly inside the OHP.
This shape/size bulb is used by the DIY community who build their own boxes so it will work if you can get it to fit.
I am a little concerned that it doesnt have UV stop built in as fitting a UV filter on a 250W may mean you need to use a smaller or more reflective screen.

The bulb outer looks a little larger than mine, I'm hoping it is the same.
This will affect the rear reflector you use as the bulb core needs to be positioned somewhere near the focal point of the reflector.
(It will also affect how close you can put the condensor lense, the further away the more light is lost)
My reflectors focal point is too close to allow a larger bulb so you may want to try other rear reflectors if you cant put the bulb core at the focal point.

I couldnt tell you if the condensor lenses you have found are good for the job. I'll try and explain how the light system works.
Light comes from the bulb and hits the condensor lense. The condensor directs the bulk of the light towards the lower fresnel in an arc. The arc will at some distance completely cover the fresnel with light, this is the crucial bit.
Each fresnel is designed to take light coming from a certain distance away. In our case for a standard 15" (310x310mm) fresnel that distance is 220mm from the light (330mm from the triplet (top) lense).
If the arc of light from the condensor doesnt cover the fresnel when it is approx 220mm away, you will lose light efficiency and can lose uniformity of the light across the screen (brighter in the center, darker at the edges).

I would advise getting a condensor designed for the fresnels we use, but there is no harm in trying if they are cheap. They may be useful for something later

It will be great to see/hear of any results you get, please giz photos
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Last edited by Chernobyl; 11th July, 2006 at 02:27 PM.
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  #599 (permalink)  
Old 13th July, 2006, 05:13 PM
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More pics

I created the ghetto shroud and did some other tidy-up work and I noticed I am getting better contrast around the edges. My next move is to build it into a rolling cabinet and put my speakers behind the screen.

The pic is from "Ghost in the Shell 2"
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Old 13th July, 2006, 05:38 PM
Chernobyl's Avatar
Projector Wizard
 
Join Date: November 2004
Location: UK
Posts: 594

Super, it looks spot on for its job.
You do have an advantage with a screen that isnt as solid as mine in that placing a speaker behind the screen should work quite well.
My centre speaker sits below the screen. It works well though and I havent felt the need to look for another solution.

I tried to get hold of my contact at the HD laptop panel Controller company (www.digitalview.com) today but he wasnt available.
They asked me to send an email which has been done.
Fingers crossed he responds in a positive fashion.

I'm in the process of getting some woodworking tools together to aid in making the new housing for the projector. To make the parts adjustable I'm thinking of getting a brazing kit and making my own adjustable mounts.
This isnt going to make it as easy for a quick setup at home but at the end of the project, I will be able to give the dimensions and locations that work best for all the parts, so it shouldnt be necessary to duplicate all my work.

Theres a way to go but the ball is rolling
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