Home made projector!

[Daniel ~]

The two edge sword of Manjuchery! Benefiting one self by benefiting others! ":O}

[luke_t]

Well, due to a lack of impatience I decided to try and buy another monitor from that well known worldly pc retailer...

I purchased their cheapest 14" tft, and i'm glad I did... it fits almost perfectly onto the projector giving 97% of the screen without cutting anything off the projector.

Its still not perfect as the light distribution around the projector seems to be stronger at one end than the other, but apart from that I am very happy with it.

incedently this non branded 14" tft had the same samsung inards as the Samsung 152V I originally purchased.

Here is a picture of the thing running, I'm still a little concerned about the max temperature that the screen should be running at... if anyone has any information on this I'd really appreciate it.

Also any suggestions on colour balance settings etc would be great.

Cheers
Luke

http://www.carshockcontracts.com/images/tmp/success.jpg

[Chernobyl]

Originally Posted by luke_t

Thanks for the replys guys,

I've included some photos of my projector setup, my projector is the 3M 9550. Sounds like its a good one to have... could you tell me why?

On the photos you can see my diy cooling method, its basically an extractor fan that is powered off the mains supply to the projector. The box channels the air through to a 1 cm gap the width of the ohp glass.

I saw on cesiums images that he cut out the corners on his ohp, I think I relly need to do this too. Also did you remove the glass from the top of you ohp, because I find it to be a heat shield... operating temperature of a screen on the projector was 34 degrees. I'd imagine that without the glass panel there it would be maybe 5+ degrees higher?

I'm going to carry on searching for a screen today, the trick is to find one you can take apart easily, without destroying the case.

Cheers
Luke

Hi Luke
your 3M 9550 is good for a number of reasons:

It has a triplet lense which gives higher definition. The third lense sits between the bulb and the Fresnel lense. It will also be easier for you to fit an aftermarket bulb, as I am about to do, as this lense is required.
(very late edit: the triplet is in fact the very top lense with the mirror. It is made of 3 lenses. The Lense sat between the bulb and condensor is called the Condensor.)

It has a cooling stage which should help keep your LCD cool.

Its light power is 4000 Lumens. The general consensus seems to say this is the minimum needed for a good result.

The ability to cool a 400W halogen should make it more than capable of cooling a 250W or 400W Metal Halide bulb as these convert less energy into heat. This is yet to be proven, I will know in a week or so.


I like your DIY cooling box I havent got round to making mine yet.
It may be beneficial to make the air flow over the top of the screen too if you consider heat to be an issue.
FYI: My screen has reached 43C in the centre while operating and still functioned fine. This may not lend to a long life though, I will be designing a more efficient cooler soon.

Yes Cesiums idea to widen the OHP display area and extend the corners works very well for 15" LCDs!. I gained me some useful screen area, enough to make all games playable. I miss the X to close Windows though, right click close works fine.
The glass on my OHP (3M 1750) serves as a route to draw air over the fresnel lense. As this lense is plastic, I imagine it could deform if it gets too warm, other cooling for the lense may be needed if removing the glass.

[Chernobyl]

Originally Posted by luke_t

Well, due to a lack of impatience I decided to try and buy another monitor from that well known worldly pc retailer...

I purchased their cheapest 14" tft, and i'm glad I did... it fits almost perfectly onto the projector giving 97% of the screen without cutting anything off the projector.

Its still not perfect as the light distribution around the projector seems to be stronger at one end than the other, but apart from that I am very happy with it.

incedently this non branded 14" tft had the same samsung inards as the Samsung 152V I originally purchased.

Here is a picture of the thing running, I'm still a little concerned about the max temperature that the screen should be running at... if anyone has any information on this I'd really appreciate it.

Also any suggestions on colour balance settings etc would be great.

Cheers
Luke

Superb, I'm glad you have the chance to use a 14" LCD. I really want to try one myself. Theoretically they will be slightly darker as they dont catch as much light, but that can be easily offset later with another bulb should you wish
Do you know if the LCD is good for gaming?

If you like the LCD and think it worthy, can you post its details in the "Good LCDs for the Home Made Projector project" thread please
http://www.aoaforums.com/forum/showthread.php?t=29076

You aren't alone, the light distribution on my OHP is brighter from 1/2 way down to the bottom of the screen. Its not noticable in most situations though.
I had a quick look to see why and the bulb filament doesnt sit in the centre of the reflector behind it. Mine needs a mod to move it into place, you may be able to adjust yours without any trouble?
I'm not going to fix this problem though as I am about to fit a new bulb type and set that up instead.

The cooling you have seems fairly effective. For Summer use it may be wise to blow air on top of the LCD too. Your operating temps are considerably lower than mine, well done.

I played with the colours for a long time and have come the conclusion not to change the colours or contrast on the LCD. Leaving them alone makes for a more natural looking picture. I make any adjustments to colour in Windows with the NVidia drivers now.
The one thing that brought the most drastic change to the colours was to use a proper screen. Since using a good screen, I hardly have to make any adjustments. A little digital vibrance here, a wee tad of gamma there is all it needs. Your mileage may vary, but I found it really tough to find a good set of colour tweaks that worked for everything while using a bad projection screen

Colour tweaking is personal though and also likely to be a different experience on different hardware.
It would be nice to know what you settle on.

[Chernobyl]

I got an email from Stephen about the Ballast today and gave him a call.

He has been very nice and agreed a good price for the complete kit:
Bulb, Ignitor and Ballast
For Cheque payments it will be £88.72 inc delivery (UK), 4% more for credit cards.

Confirmation of the price should arrive tomorrow.
I'll be placing an order next Tuesday. Once satisfied it works, I'll put a post up in this section
http://www.aoaforums.com/forum/72-links/


its looking good

[pfil]

Hey Chernobyl, I've been lurking in the forum a week or two. Love what you're doing. Can't wait to see what your MH lamp does as I'm going to try it as soon as you post your results assuming they are favorable. I got a 4000 lumen projector and am waiting for a good deal on LCD's on ebay.

That said, I got a crazy idea, I'll see what everyone thinks. What if I got 2 of the exact same lcd and stacked one on top of the other to try and improve contrast ratio? I'm sure blacks would be blacker and of course you'd block twice as much light, needing even more lumens but assuming you lined everything up perfectly and avoided parallax, would the colors and whites be OK? Any thoughts? It appears you can easily get a projector with the same specs as a high end projector with XGA resolution and high lumens but I've seen projectors with 2000:1 contrast ratio, most lcd's I find or 400:1 or so with expensive one's being 1000:1. No 2000:1 monitors.

[Gizmo]

Projectors that achieve high contrast ratios usually use some kind of MEMs technology (like TI's Digital Light Processing) AFAIK. No, you can't simply stack the LCDs, because each LCD typically has a diffuser for the light source and the LCD drive electronics mounted BEHIND the LCD. Attempting to separate these components in order to shine light THROUGH the LCD (which is what you are talking about doing) would result in destruction of the LCD panel.

[Chernobyl]

Originally Posted by pfil

Hey Chernobyl, I've been lurking in the forum a week or two. Love what you're doing. Can't wait to see what your MH lamp does as I'm going to try it as soon as you post your results assuming they are favorable. I got a 4000 lumen projector and am waiting for a good deal on LCD's on ebay.

That said, I got a crazy idea, I'll see what everyone thinks. What if I got 2 of the exact same lcd and stacked one on top of the other to try and improve contrast ratio? I'm sure blacks would be blacker and of course you'd block twice as much light, needing even more lumens but assuming you lined everything up perfectly and avoided parallax, would the colors and whites be OK? Any thoughts? It appears you can easily get a projector with the same specs as a high end projector with XGA resolution and high lumens but I've seen projectors with 2000:1 contrast ratio, most lcd's I find or 400:1 or so with expensive one's being 1000:1. No 2000:1 monitors.

Hi pfil
Welcome to AOA on behalf of the cool chaps who run this site.
Thanks for joining in, great to have you here.

I cant wait for the MH bulb , I hope it really does more or less drop in.

Hehe, your crazy idea has been discussed in a few places but unfortunately wont give a good result. I'll explain as best I can...

When an LCD passes light with no filter, there will be losses in the light power.
To pass white light in a colour LCD, Red Green and Blue colour filtered Liquid crystals are used. Each one can only pass the one colour in different brightness levels.
To produce 1 white pixel, a red, green and blue pixel are needed.
Each of these coloured pixels blocks 2/3rds of the light, so immediately just passing through the filters, you have lost 66% of the light.

The LCD is coated on at least one face with a polarising filter. Losses will occur travelling through both the LCD and the filter(s).

Not all the light hits the LCD crystals, there is a tiny space between each one which will also block light.

There is a coating thats helps light dispersion too which will reduce light power (I just read you post Gizmo, thanks for the reminder )

Any light absorbed by the LCD panel would be converted to heat.

I estimate that the max light that an LCD will pass is somewhere between 10% and 20%. Stacking 2 high would give you only 15%ish of the light you have with 1 LCD.


Its nice you are thinking about ways to help this though, keep it flowing

[Daniel ~]

If this was a sport I'd be a fan! Great work guys, really nice to see such innovation!

[luke_t]

Hi guys,

Well after playing around with the projector all day at work, I took it home and gave it a blast against my bedroom wall.

The result was pleasing... especially as my wall is a cream colour. I think I'm going to have to paint a big white square on my wall now!

I also need to rebuild my mount for the tft screen as it was originally designed for a 15" screen, with the 14" on a little light leaks out from the sides (as seen on the bottom of the attached images).

What I'd really like to know is a good UK based source for buying more of these 36v 400w halogen bulbs for this projector, again any suggestions much appreciated!

Chernobyl, I like the idea of sticking a MH bulb in the unit, especially as the bulb life seems so much greater! I'd love to seem some photos of that when its done. Will the MH bulb directly replace the halogen buld without modification? I'll take some photos of the inside of my projector at some point!

PS. please excuse the quality of the photos they were taken on my mobile phone camera

http://www.carshockcontracts.com/images/tmp/ohp3.jpg
http://www.carshockcontracts.com/images/tmp/ohp4.jpg
http://www.carshockcontracts.com/images/tmp/ohp5.jpg

[Daniel ~]

Something I feel might be seeeing some neglect in your projects, Has anyone looked into how a decent screen might improve the display?

What resolution are you using Luke?

[Chernobyl]

Originally Posted by luke_t

Hi guys,

Well after playing around with the projector all day at work, I took it home and gave it a blast against my bedroom wall.

The result was pleasing... especially as my wall is a cream colour. I think I'm going to have to paint a big white square on my wall now!

I also need to rebuild my mount for the tft screen as it was originally designed for a 15" screen, with the 14" on a little light leaks out from the sides (as seen on the bottom of the attached images).

What I'd really like to know is a good UK based source for buying more of these 36v 400w halogen bulbs for this projector, again any suggestions much appreciated!

Chernobyl, I like the idea of sticking a MH bulb in the unit, especially as the bulb life seems so much greater! I'd love to seem some photos of that when its done. Will the MH bulb directly replace the halogen buld without modification? I'll take some photos of the inside of my projector at some point!

PS. please excuse the quality of the photos they were taken on my mobile phone camera

Hi Luke
Cool pics

I ordered some spare bulbs from Ebay. If they are the same as my 36V 400W, searching for A1-239 or 64663 will find them. They were around £15 for 3 delivered.

I'm having a little trouble sourcing the MH lights for a decent price.
The UK supplier I was talking to has gone back on the pricing he gave me.
He also didnt include the lamp holders @ £19.60+vat!
He's been asked for further help with the price but it doesnt seem he can match buying from Germany.

The German supplier cannot get stock yet after the factories closed down for New Year, so I'm playing the waiting game. We're in contact via email, so hope to get results within the next 2 weeks.
I'll post details as soon as I have success ordering.

Good luck with the screen on the wall. Find the brightest Matt White you can unless you wish to use a paint on screen coating like ScreenGoo.
A good screen makes all the difference

[Chernobyl]

Originally Posted by Daniel ~

Something I feel might be seeeing some neglect in your projects, Has anyone looked into how a decent screen might improve the display?

What resolution are you using Luke?

Hi Daniel, I've done quite extensive research into how a screen will affect the picture, backed up by the use of only one good screen so far unfortunately.
Speaking to other people who use a proper screen confirms what I found.
This is the first post made after returning back to the screen and discarding the sheet.
http://www.aoaforums.com/forum/showp...&postcount=104

I'm using a 5ft, near 40 year old but very bright screen, Gain unknown - higher than 1:1.0. It transformed the projector, I cannot recommend sorting the screen out enough as everything is suddenly easy to setup and a real pleasure to watch.
I will be getting a larger screen in the fullness of time, full details to come.

The basic screens come in Gains of 1:1.0, 1:1.1, 1:1.2 and 1:1.3
There are higher gain screens but the cost goes up dramatically, many tend to have limits on viewing angles etc.

Were you looking for any other information Daniel?

[Daniel ~]

No that covers it, just wanted to mention it. ":O}

[Cesium]

ahh luke, a 9550, how did you manage to land yourself one of them? The only place i could think of is ebay...wish i had $75 to spend

Chernobyl, i dont think i'll be upgrading my bulb anyitme soon, my ENX's are working just fine, and as i have 4 of them, thye should last some time hopefully

my brother is posting his process at his website at http://www.gmeel.com/lcdproject/

i bought my screen from newegg

[Daniel ~]

Tell your brother we'd be happy to publish it for him.