Home made projector!

[Chernobyl]

Hi Chaz,
Once you get your new screen running, you will notice a dramatic improvement in visual clarity and brightness. You got a good taste of it with a piece of paper. Bright paper has a gain of about 1.0, maybe 1.1. Your screen is likely to have a gain in the range of 1.0 to 1.3.

I've done a bit of thinking about using a MH bulb in the 9550 OHP.
Previously while researching, I noticed that OHPs with a cooling stage gave a lower light output. I also found another OHP using the same bulb as you (and my old bulb) that gave 6000+ lumens vs our 4000 lumens (with that original bulb).
The 6000 lumens OHP also had a bulb lifespan of 50 hours vs my OHP which was 4000 lumens and up to 270 hours life.

It seems as though this bulb can be overdriven to produce 6000 lumens at the expense of its lifespan. I propose that your bulb is being driven in such a way.
If you use a 250W MH bulb I have no doubt it will not be as bright as the bulb you have. I suggest the use of a 400W bulb for your system. This is very practical in that the extra UV from this bulb should not be an issue as you have a cooling stage mirror. My hope is that the mirror does not transmit all UV light.
If this is not so, a real UV filter can be found. If you decide you need one I will help with sourcing the best product for the price should you wish.
The 400W MH bulb will produce much less heat than your current bulb, so that is not an issue

From what you are saying about severe blurring at the screen edges, your focal lense at the top appears to have imperfections affecting its performance. It may be necessary to find a better quality lense. This is also a prime opportunity to make your focus top notch!
I havent looked up buying these lenses yet, but will help find one if you need.
I noticed your focus lense/mirror are enclosed. It may be a good idea to check a few skips or businesses closing down to see if there are any broken OHP's you can take the complete unit from. It doesnt have to be the same, just a lense with uniform focus. I imagine theres a bit of pot luck involved.
(edit: I found that my focus problems disappeared when I split the fresnel lense - see much later - and had the upper part of it above the LCD. The focus is now taken from the top fresnel lense and is great across the whole screen)

If you are a gamer, I suggest using a wired mouse. The lag on wireless versions takes some getting used to and at times is unacceptable.
This is what I have found. If you can test for yourself before purchase, that would be best.
(edit: newer wireless mice like the MX1000 etc are brilliant for gaming)

Your setup is nice from the start as you are able to lay the LCD straight on the glass due to the cooling stage preventing it getting too hot. This improves brightness and colours compared to having a gap under the LCD to blow air under it. With the 250W MH bulb, I am now able to do the same fortunately
If you find the LCD gets too hot in the summer, angle the fan towards the LCD a little, it should promote more air movement on the surface of the LCD.

I noticed you have left the electronics exposed. The covers that were over them originally should go back on with little modification. This would help guard against accidental spillages, bits of metal and static.

lol, I had a similar problem with a little light escaping from the front of the OHP. I was chasing the source for a while before I smacked my forehead and realised why. Since changing the bulb and its position, its no longer a problem, just luck I guess.

Not sure if I missed anything. Ask again if I didnt answer it all.

[Chernobyl]

Originally Posted by Chaz

I got the shock of my life today. I dismounted the LCD from the OHP to clean it, put it all back together then powered on. Broken lines across the screen. I skipped a heartbeat, I thought I had already broken it. After shuffling the LCD around a bit it flicked back on, so I thought it must be a poor contact. I removed the metal plate from the main circuitboard, and saw that one of the two data connections, linking the main circuitboard and the additional smaller one, had come unlocked. I put it back in, locked it down, and thankfully everything works great now...

Today I painted a screen onto the wall, and it has made a nice improvement (see attached photo). Everything is slightly brighter, but the colours are obviously far better, almost perfect. In CS I can now pretty easily read the 'who killed who' information at the top. Also I stapled - yes, stapled - binliners onto my curtains. With them closed its lovely and dark, dark enough to use windows or play any game.

Hahaha
brilliant, I was kidding about the bin liners, honest

I'm real glad you have the colour balance etc restored by the painted wall and that you can read the edges now. That saved a bit of work. If you still wish to get another lense, I will help.

It is frightful when it suddenly doesnt work. Its scary publishing your work as well cos if u mess up, theres no hiding it Glad theres no damage to the LCD. These Iiyamas seem very robust unlike the BenQ that went into slow decay before death.

Have you got the graphics power to enable anti-aliasing? It has a great effect, especially on Counter Strike Source.
I have to say the result looks top notch !!

[Chernobyl]

One thing I forgot to mention.
If you can paint a really black, non reflective border (or use felt) around the screen, it makes the screen look even brighter due to the contrast difference

[Chaz]

Well it's been 5 days and the bulb is still going good. I've mainly just used it for games and films, since it's not really suited to windows use because of the fuzziness around the edges issue. I've also got two more bulbs on the way, so I'll let you know if they fit alright and also when the current bulb dies.

[Chernobyl]

Yeah do let us know how long they last.
I read that those bulbs can last 100 hrs in low power mode.

When reaching the end of its life the bulb glass will become smoky and the picture will look a little yellower. This made me think that the next bulb I fitted was brighter.
In truth, some bulbs really were brighter but for the most part it was my imagination.

How are you finding life with your projector?

[Chaz]

It's brilliant, well worth the £200 spent on it. I'd recommend anyone considering making the jump to go for it.

There is some bad news though... I tried playing Doom 3 on it the other day, and it is totally unplayable. Because it's so frickin scary! I played half a level (alpha labs!) before I pussied out and closed the game! The brightness is actually absolutely fine. There's no trouble with not being able to see a thing, well, it is still a bit dark, as you'd expect. But it looks just as bright on the projected image as it does on my CRT.

Forgot to mention, I'm running the bulb in low power mode, it looks equally bright as in standard mode. I think when I switch to the new bulb I'll record every time I turn it on and off, so I can work out exactly how long it has lasted.

[Chernobyl]

Ace, yer projector scared you
I agree, the feeling of immersion in games is something else!
I played Virtual Pool 3 the other day, its really awesome.

At £350 I spent it was a bargain, for the £200 you spent, its incredible!
Any more piccys?

[Chaz]

New bulbs are here, havent had a chance to try them out. The pics attached show the blurring issue. The first is a photo of the center of roughly the center of the screen, lovely and crisp. The second shows the corner of the screen - you can see it looks smudged up towards the center of the screen.

Chernobyl, can you please post a direct link to that german supplier? I know it's been indexed in your other thread, but it seems I *still* dont have enough posts to access that area! Great system, admins...

[Chernobyl]

Chaz
hopefully this supplier has the parts you need as well as the bulb.
If you email him, he should be able to tell you about his replacement lenses.
Dont give up if he doesnt appear to sell what you need, drop him a mail.

Here is the full post I made about him in the 'Useful Links" thread.

Good luck.



http://62.75.177.102/shop2/index.php...0cd968c622f288
Stephan Stange is the chap running the shop.

This guy in Germany came through with an awesome HRI-TS 250 W/D Metal Halide kit for a superb price (see bulb description below). This bulb also should have the name UVS tagged on as it has built in UV Stop which also blocks a lot of Infra red heat. The bulb is rated for at least 6,000 hours operation and may even be 20,000 hours. I suspect it is 10,000 hours, more than a years continuous use!
He doesnt often have stock, so snap the deals when you see them.


The bulb has the following characteristics:
CRI 90 - very good
5100K Daylight colour temp
250W
20,000 Lumens
UV Stop
Smallish size/fittings fine for an OHP
Life 6,000, 10,000 or 20,000 hours (update: 6,000 hours, 3/4 of a year continuous)

The site looks as dodgy as you like, but he responded well to questions by email and sent the goods exactly as promised. To read the site, translate it through Google. When purchasing, use the real site as the Googled one doesnt work.

He does many parts including fresnel lenses, rear spherical reflectors, 400W bulb kits etc. Remember for a 400W system, you will likely need a UV filter to avoid damage to the LCD.

I got a complete kit of Bulb, Starter, Ballast and bulb fittings. The bulbs can only be bought as part of a full kit. I also got a rear reflector (which turned out to be more of a 1/2 sphere and larger (and better) than the one in my 3M 1950 OHP). Total cost 103 Euros including delivery to the UK!!

HRI-TS 250 W/D Metal Halide Bulb Description:

Full specs can be found from this page
http://www.radium.de/produkte_overvi...1855,2498,2565

250W rated power consumption
HRI, HQI and HTI all appear to be similar. If the rest of the bulb spec fits, you should be able to use any of these types. Check bulb life is correct.

TS is a double ended power connection

DL Daylight rendering. Typically above 5000K colour temp.

Metal Halide is a much more efficient bulb than the Halogens in most OHPs.

Bulb Considerations when finding a bulb:
Power rating (Watts)
Light power (Lumens. 250W typically 20,000 and 400W 36,000)
Colour temp (around 4800Kish to 5700K for Daylight rendering)
CRI (>=90 The Colour Rendering Index)
Fitting/size
Life (typically 2,000 to 20,000 hours)
UV Stop

[Chaz]

Excellent Chernobyl, many many thanks. You gotta love the google translation:

"Metallhaloidelamps of acres 5 times more brighter than normally haloidelamps"
"daylight MH lamps absorb light which is equal ton the natural"
"Beamer in the self-'s building"


Apparantly the 250W version comes with UV filter, and the 400W one doesnt. Other than that, I dont see why not to get the 400W one, it's only slightly more expensive and puts out 16k more lumens than the 250w one.

Too bad he's out of stock, I guess it doesnt matter that much since I have two more halogen bulbs here and I dont have the cash to upgrade right now. The original bulb I'm still using seems to be on it's last legs, but it may well just be my imagination. It was quite a hot, bright day today.

Photo: me happy with my 2.3m diagonal (91.5 inches, 7.5 feet) screen.

[Chernobyl]

haha
we love Google.

Yes its a case of catch that supplier when you can. The parts can be bought here for around twice the price. I would prefer to buy off him though as he has selected his components based on their quality for a projector. You cant go wrong
Drop him a msg, he will tell you when he's likely to have stock. You better be early in the Queue !!

Your picture looks great! Lovely size too.

I have a small report on UV, coming next.

[Chernobyl]

I've been observing the results of UV burn in on the LCD and how/when it occurs.

After leaving the projector for a number of hours with the same picture on the screen, the picture leaves a very light trace of itself like a watermark.
It does fade away especially if the projector is left off for a while. The longer the burn in is allowed to have, the longer it takes to go away. A severe burn in is mostly gone in 24 hrs.

The burn in was worse when I ran the projector without the glass in the lid of the OHP. With that glass replaced, it appears enough UV does get through to affect the LCD a bit.
Over time the screens colours will fade from UV, I dont know how long the screen will remain serviceable. After 1/2 a year of use, the colours are as bright as ever and the "burn in" is a non issue, it is very faint when it happens and goes away.

If you are concerned about UV burn in, you can take 3 approaches to prevent it.

1) Dont use it much Not likely!
2) Replace the LCD if it gets bad enough. Pretty cheap seeing as 15" LCDs are £100 and are going to last at least 1.5yrs at least I reckon. Much cheaper than changing the bulb on a normal projector every 1000 to 3000 hrs!
3) Fit a UV Filter.

Fitting a UV filter will take about 20% of the light away which means having a smaller screen if not bright enough or fitting a brighter bulb.

If making a new projector with an MH bulb, I recommend the 400W system and a UV filter. The extra cost of the parts is minimal and unless you cant cope with the extra electric use, its extra brightness/screen size will be a bonus!

I am not worried about the UV burn in at all on my system but would really like a 400W bulb, so I will do this someday

[Chernobyl]

Haha Chaz
your picture has given me an idea, you can project a tattoo onto yourself.
You look as though you have a japanese bandana on.
I swear you have tights on your arms too

With enough ingenuity, a complete outfit could be projected onto you if you wear all white.
its late Thats my excuse and I'm sticking to it!

[Rondog]

Originally Posted by Chaz

Excellent Chernobyl, many many thanks. You gotta love the google translation:

"Metallhaloidelamps of acres 5 times more brighter than normally haloidelamps"
"daylight MH lamps absorb light which is equal ton the natural"
"Beamer in the self-'s building"


Apparantly the 250W version comes with UV filter, and the 400W one doesnt. Other than that, I dont see why not to get the 400W one, it's only slightly more expensive and puts out 16k more lumens than the 250w one.

Too bad he's out of stock, I guess it doesnt matter that much since I have two more halogen bulbs here and I dont have the cash to upgrade right now. The original bulb I'm still using seems to be on it's last legs, but it may well just be my imagination. It was quite a hot, bright day today.

Photo: me happy with my 2.3m diagonal (91.5 inches, 7.5 feet) screen.

Where did you get the background, mate?

Can you give me a link, or send a copy?

[Krusty]

Alright, you got me interested. Two days ago, I found a tomshardware link to the tutorial over at ocforums.com. In the past two evenings, I have started searching for overhead projectors. Once I found a few, I started looking for LCDs.

That is when I found this thread. I was looking around for an answer because I noticed a 15" LCD would not fit on any overhead projectors that I could find. I managed to find the answer in this thread along with about a million other details as I read every word on all 15 pages. My eyes are tired now but I think I have been convinced to give it a try.

As of a few minutes ago, I have concluded that I only want to take on this project if I can beb ensured excellent quality. As it seems your basic overhead projector requires a lot of upgrades to function well, I think I am going to try my hand at building a LCD projection system from the ground up.

My first step is to figure out what sort of parts I may need.

As you guys appear to swear by metal halide lights, I figured I would start there. A (very) quick search brought me to www.prolighting.com where I can get a 400w ballast kit (http://www.prolighting.com/sousm400q-k.html) for $65 and 40w bulbs for $17 (http://www.prolighting.com/mh400-u.html). Is this pretty much what I should be looking for when it comes to lighting? The product description there says "Uses: Downlighting, floodlighting, corridors, lobbies, walkways; retail, commercial, industrial." No mention of LCD projectors ;-)

Next up is the frensel lens and projection lens. Checking out www.lumenlab.com shows that they have some but I really have no clue what to look for here. This also brings me to my big important question:

Does anyone have a link to a detailed tutorial on building a quality LCD projector without the use of an overhead projector? I'm looking for general assembly tips, detailed item purchasing tips, and some tips for creating the proper focus and screen size. I don't really like jumping into things half ****ed and still have a lot of questions that have popped up doing some preliminary research on the subject.

EDIT: LOL. It censored ****. That is a word that refers to firing a gun, male chickens, and genitalia.

EDIT2: Found a little simple projector theory people may find interesting
http://www.diyprojectorcompany.com/theory/lenses.htm

[Chaz]

Lumenlab sell plans to make your own LCD projector without an OHP. To be honest, the upgrades to your OHP setup do make it better, but I was suprised at how good it was as soon as I powered on. The only optimisations I've done are paint a screen onto my wall, tweak gamma settings in games, and just clean the OHPs lens/glass top etc.

Not to depromote this thread, but there are also loads of great discussions on DIY projectors in the 'Moving Image' forum of the www.diyaudio.com forums. Many people there use OHPs, and other people have made their own using the lumenlab plans (which I've heard are very good).

[Krusty]

Found the plans for free. Go me!

http://www.diyprojectorcompany.com/

Now I just need to find me a metal halide bulb/ballast that connects from two ends (the one I found so far screws in like a light bulb), a Fresnel lens > 12 inches (I'm thinking about using a 17" LCD for higher resolution, and a good triplet lens. Everything else is learned with some experimenting.

[Chernobyl]

Hi,
I checked out the bulb you were looking at earlier and it wont be suitable.
That one has a CRI of 65, you need a CRI of at least 85, preferably 90 to render the colours correctly. Also of note is the central light frequency of the bulb - 4000K. I recommend 5200K up to 5700K. It doesnt matter how good the CRI is if you are using the wrong colour bulb!
Above 5700K will look more blue, below 5700K will look more yellow.
4000K will make you unhappy!
You will need a large rear reflector for that bulb, they are more expensive.

I recommend the HRI, HQI and HTI - TS bulbs. These are available in the correct CRI and light spectrums. They may not last 20,000hrs, but they are the most suitable for the job.
Mine is a HQI-TS 250W UV, CRI 90, 5200K, 6000hrs
It is a small double ended design that can take a relatively small rear reflector.

Your plans to use a 17" screen are my next project too
Be sure the Fresnel lense and UV filter you buy can take a 17" screen (you do seem aware of this).
The rear reflector can change the central light frequency. Be sure to get one people are already using for OHP's or one that is known to be neutral.

Regarding modifications to the OHP:
If you want higher res than 1024x768 I recommend not using an OHP and building your own box.
If 1024x768 is good for you, use a 15" screen and OHP (triplet lense), the modifications I have made are as follows:

1) Replaced the bulb with a MH type and fitted a cooling fan onto the transformer. This has a number of advantages.
a) better colours
b) brighter
c) lasts longer
d) much cheaper in the long term
e) much cooler running (allows LCD to lay on the glass, gives better/brighter colours)

2) Removed the fan guard to reduce air noise.
3) Fitted a shroud over the LCD to prevent light escaping into the room
4) Fitted a fan to blow filtered cooler air on the LCD to extend its life.

lemme know if I missed any info you need.

[Chernobyl]

ooh, forgot
5) cut the plastic edges away inside the OHP lid that were blocking light.

[Krusty]

I wound up springing for parts that should help to ensure I am satisfied with the results. At www.diyprojectorcompany.com, they had instructions for a home made 15" projector http://www.diyprojectorcompany.com/designs/mkIII.htm

So I decided to do that and purchased the lenses, mirror, and glass direct from them. For my lighting, I saved a few bucks and got a 400w HPS quad core ballast and a 400w hps e39 s51 lamp that is designed to fit into a sodium ballast. The ballast, capacitor, and ignitor set me back about $70 shipped and the lamp set me back about $40 shipped but I think I will be satisfied with the results. Color is 5.2k and a that was a recommendation from a guy at the diyaudio forums. There's a lot of people there that have built their own projector.

As for the 17" LCD thing, I decided to stick with 15" for now. I'll do a 17" project if I determine this one to be a huge success ;-)

EDIT: put the wrong url in for the plans I'm using.