Did It Myself Video Projector

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I am in <b>AWE</b>. Forgive me, i realize this is a forum with some young people, myself relatively included, but holy ****.

It took over a month for my ViewSonic vg150 to get here. Abso-freaking-lutely forever, slightly over a month. Projector was here after a week and a half, and I've been waiting ever since for the the forsaken LCD to get here. Well, it finally showed up Monday.

I put the thing together yesterday, just racing through plans and mad jury rigging. A squirrel cage fan, refridgerator fan, a couple lego bricks, two stands and two whole rolls of duct tape later (plus a whole lot of work), and the things together. Completely beautiful.

I pretty much just disected the LCD monitor, and ripped out the matrix and the control circuitry. I have legos duct-taped down around the perimitere of the projector, elevating the lcd matrix a little over half an inch above the projector surface. I knew I needed some airflow, i so scounged around and found a pretty nice fan intended for a bathroom ceiling. pretty nice CFM, and relatively queit, especially considering what its pushing.

The thing overheated almost instantly. It was almost singingly hot to use. but it looked freaking awsome. amazing, already, and i hadnt even started tweaking. definately knew i couldnt be stopped, right then and there.

I had a cheezit box lying around, so I sliced off one of the sides and used it to duct the airflow from the squirrel cage fan to under the LCD. That should work to keep it cool, but there was still a HUGe heat problem.

I realized the projector was scorching hot. It's got a 575 watt hetal halide stage light causing there to be a world of burning and heat and stuff like that in that little black metal projector. it was way hotter in that black box than it had any right to ever be.

Flaw one is that it just has a single fan in the box. Flaw two is that the box had no airtake. Flaw three is that the fan barely spun. Added some oil to the fan, and masking taped a side up. Found a random fan from a refridgerator just lying around, so I traced a circle a little bigger than that (using a compass) on the masking, and broke out the jig-saw. Drilled some holes and bolted the fan down. The wiring inside the box is hard to get to, so I just put a 120v line on the fan and called it a night. Woulda been nice to do a decent job, but man, i was minutes away from completion.

I reassembled everything, duct taping the legos down to the side of the projector, placing the panel gingerly down on top. Taped the two stands the whole monstrosity sits on back together and realigned the cheeze-it airflow deviceto keep the LCD cool. Taped everything down into place. Attached the control circuitry for the LCD "safely enough" and started plugging things in (2 fans, 1 LCD and 1 projetor).

Its been running ever since.

Dad brought back the $200 heat scanner today. 102 degrees at the hottest, after over 12 hours of use. Most of the LCD's right around 95, which is perfectly fine for it.

The image is great. We'll start with the bad. Unfortunately, the LCD's a bit bigger than the projector, so I'm missing some of the screen. To worsen things, because i have to elevate the panel, i get even less of the screen visible. By moving and rescaling DScaler and PowerDVD, we can perfect our viewing area, so the image we want appears perfectly on the screen, but its not as sharp as it could be, since were not using all the pixesl.

The image is a bit over 800 x 600 pixels visible, which is still a whole, a certifiable shitload oh pixels. I would <b>definately</b>like more, but i can live. Besides, the s-video source thats got the PS2 plugged into it isnt even 800x600 in quality, its already stretching.

I might almost say the 350:1 contrast ratio of the VG150 makes it LESS suited to this job, as evident in gran turismo 3 in Smokey Mountains, where you have some uber high contrast scenes, jumping from brightly lite mountain side to darkened forest paths. If you've got a fairly constant light balance game or movie, you can tweak you gamma settings perfectly, to any game, but things that change frequently are harder to fine tune. You can software reduce contrast ratio, but its just not the same thing. I initially bought the high contrast ratio system thinking the highest contrast system i could find would be best suited to having a 17,000 lumen bulb shown through it, but it turns out that its actually possibly overkill.

But regardless of those things, i'm still in totally new world. This is unlike anything i've ever seen before.. I can have lights on, and the image is still clearly visible, its so bright. Not a dream of a concern about brightness. You can get some really amazing colors making up some pretty amazing scenes. Widescreen is the greatest creation ever.. My friends are playing Grand Theft Auto right now, and i cant seem to stop the drool that keeps rolling off my lips. This is the best $350 I've ever spent in my entire life, without any quesiton.

What i'd really like right now are three things. One, a photoshop style Curves for brightness, two, a way to have presets with it, and three, a way to run a resolution something like 824 by 755 using the pixels at the center of my screen.

gonna start playing with powerstrip now in hopes of added tweaking. if anyone knows any other tools, i'd be appreciated.
I'm using a Bell and Howell 588A projector, or something close to that. Thats what I was told it is, although I couldnt find any information on it. Uses a standard 575w metal halide stage bulb, which i found stocked at a local store for $9 each. Just make sure the damned thing is bright, your average 4000 lumen projector just cant and wont cut it for a 7 foot tall widescreen image.

I used a viewsonic VG150 for the matrix. Its just plugged into my computer, which has a tv tuner card, complete with s-video and composite in.

The LCD wasnt at all hard to disassemble. Piece of cake really. None the less, it was still literally the scariest thing I've done in my entire life - $280 of LCD isnt something I can afford to break. Just go slow and make sure what your pulling can be pulled out before you use too much force.

the squirrel cage and refridgerator fans i just had lying around. genero 120v parts. squirrel cage is regular genero bathroom fan, but the refridgerator fans is really nice one. make sure you've got duct tape. lots of duct tape.

I tried using powerstrip to adjust the image, and i thought i had it down, but it was horribly horribly buggy.

Great work!
Could you explain your setup more detail?
What type and brand of MH bulb do you use? What type of lamp-housing? is it really $9 for complete set (bulb, ballast, ignitor, capasitor & housing)?
With image about 600x800 pixels, how big your image on the screen?
If you want whole pixels (1024x768?) appear on the screen, try to add 1 double-convex lens dia. 3" ,f=2" in front of LCD panel, ajust lens distance from LCD (approx=16"), so the projection image (you can use white hardpaper as test screen) is approx=3" wide.
Put your projector lens after that image, ajust and voyla! you will get the whole pixels you want!
Does pixellete on the screen noticeable?
Contrast ratio 350:1 is not enough? Is it possible to ajust contrast from the monitor button?
Please,get some screen shot, can't wait to see it!

Gunawan W.
The pictures should explain the physical setup pretty well. Coming *soon*. Sorry.

Its $9 for just the bulb, but thats all i should have to replace in the setup. Its a 120 V MH setup, or the equivalent DC full bridge rectified equivalent (cant remember which).

The projector itself was circa ~$40 on ebay, and damn slick. Screw the fancy 3m and Dukane projectors everyone else is buying, go straight for a 500+ watt solid steel tank of a projector, designed simply for a shitload of light.

At about 800 x 600 pixels, i've got a 12 foot wide by six and three quarters tall image. the image size really just depends on how far from the projector the screen is. light isnt really a problem, and really wont be any problem pretty soon.

i'm just using sheets right now to bounce the image, which sucks for a number of reasons. first off, the screen is rippled from the unstraight sheets hanging from a suspended rope. second off, third the projectors light passes through the sheet, third the light gets absorbed, and third the light does what it should which is non-reflectively bounce of the screen. the light output is actually still more than adequate as is, but with an improved viewscreen, i probably wont need to turn off the lights for a nice sharp and clear image. to facilitate this, without spending +$500 for a monstrous second hand screen, i'm builidng four flats that will be four foot wide each and about seven and a half feet fall, with hinges to collapse down for easy transit. because of the hinges, i dont have to use the whole bredth if i dont want to.

as for the actual construction thereof, i will probably pull some heavy sheets tight over a framework and i've got some extremely matte white paint here ready to begin drenching the sheets. i'm probably going to have to masking tape the seams when i want to use the setup, but its a worthy price to circument paying at least +$500 for a real second hand projection screen somewhere. should be under $50 in parts and work <b>great</b>. And it'll give me a 16 foot by (nearly) 8 foot surface. Not quite 16:9, but it needs to fit in standard house clearance and it'll be good for 2.35:1 movies.

the optics are a problem. the ONLY way to be able to use more of the unused LCD space is to have a bigger fresnel, cause something has to catch the light before it enters the LCD to redirect it towards the collector lense overhead. its just the way the optics work out. i really need a bigger fresnel, and there is no substitute. if i find a nice 15 inch or bigger one cheap enough, i'll be building myself a nice custom box to go with. i'd like to find some 19 inch plus fresnesls so i can build fancy projectors for rich friends using nice high res 18.1 inch LCD's.

Pixellation is noticable only when viewed extremely closely. Not nearly as much screen door effect as i feared, really pretty much none unless your merely inches away looking for it.

the 350:1 contrast ratio is almost TOO much. If you've got a movie with both light and dark shots, the light ones are all to bright and the dark ones are all to dark. i can turn down the contrast some in software and using the monitors OSD (on screen display - for tweaking things like contrast), but its fundamentally a problem having a contrast ratio of 350:1 on an LCD, something that the OSD and its cheap tricks cant circumvent. I'd recommend a 300:1 as the perfect contrast ratio, no higher and no lower. But yeah, I'd still choose 350:1 over 250:1. 250:1 probably would give washout.

i really want to make a version 2.0 that uses some sort of zoom lense setup, something so i can adjust the image size on the fly. i'm working on the microcontroller code for the single axis stepping motor-controlled rail slides, which i'll be using to hopefully create this monstrosity. if i cant find a nice fresnel though, its all for bunk. it'd be nice to have rangefinding code in too, so the damned thing can autofocus, but i'm not sure if i'm willing to spend the sanity points and hair required to get this 8 bit scenix microcontroller to do the precise and acurate trig i'm going to need it to do. looking for a better way.

anyways, i'm really sorry about pictures, or their noted absence. my friends making me return his dremel that i havent used in forever before he'll lend me his digital camera, which is fair enough, but i think i might've left the dremel at my dorm. should be able to fix that soon.

if anyone knows good sources for 15 inch or bigger fresnels that may somehow in some way be suitible to this project, please please please lemme know.
Contrast ratio and washed out dark and white areas

The problem with the light areas being to light and the dark areas being to dark is not really an issue with the contrast ratio of the LCD. This just tells you the difference between the darkest possible pixel and the lightest possible pixel.

The problem you are describing sounds like it is related to your gamma curve being incorrect. Computers generally use a different gamma curve the TVs (because of the difference in display color temps) so this would not be surprising. If your video drivers support it you might want to try playing with your gamma curves to see if you can make the picture look better.

With projectors, the higher the contrast ratio the better, as brighter whites can make the absolute black level look darker (always a problem with digital projectors).

the opacity of a "white" pixel should be - pretty much - neglidgible (sp), no matter what your contrast ratio. typically, the contrast ratio just states how dark a "black" pixel can be, and in this case, its actually far darker than i need it to be.

its actually dark enough that i have to adjust the curves (although the gamma curves adjustment i have is way sub standard) so that the low levels are a bit higher than they should be. But i dont really have any way to compensate for this on the high end, so i get whiteout for brighter scenes. If whatever i'm watching is just dark or just light, i can set it fine, but when its both, the hihg contrast ratio and my sucky video card gamma settings makes for a bitch of a time.
LCD issues

Myren, it sounds like you're experiencing a problem with the LCD not being able to represent all colors correctly. I was just reading an article about LCD monitors the other day, and they spoke about a problem that sounds like yours. Namely, that the lower end of the brightness scale was not represented well, and went to black way too soon. (If you want to check it out, its on: http://www.tomshardware.com/ under the LCD monitor comparison) Unfortunately, there's not really a way to fix this without buying a new LCD screen.
lamp again

Sorry I ask about lamp again, because it's one of the important thing to successfully diy projector.
you're using 120V 575W Standard Metal halide Stage bulb.
How's it look like?
is it possible to know what type of bulb if it's dead and needs replacement?
I searched in local store for MH bulb, they have 150W MHNTD type (stick model with connector at both end), complete set with flood type reflector housing (same as flood lamp to illuminate billboard), it's for $30 !
So, please, if you don't mind, give us more details of your lamp. What is the brand, type and the housing type?
Is there any website about that lamp/bulb to look?

standard 575w metal halide specification

You posted a wealth of valuable information in this forum. Thank you!! When u say standard metal halide stage bulb, do they use 120V? Do u need a transformer and a larger fan for cooling? Joseph.
Myren said:
I'm using a Bell and Howell 588A projector, or something close to that. Thats what I was told it is, although I couldnt find any information on it. Uses a standard 575w metal halide stage bulb, which i found stocked at a local store for $9 each. Just make sure the damned thing is bright, your average 4000 lumen projector just cant and wont cut it for a 7 foot tall widescreen image.


I think the bulb Myren is referring to is actually a "halogen" bulb, not a metal halide. It is a 600watt DYS Overhead Projector bulb that has been used for many years (decades?). I have an OHP that is at least 25 years old the uses this bulb. It is not energy efficient and definitely requires a strong fan, but it is a "quick and dirty" way to get a good bit of light for cheap. It can be run from standard 120v AC power...no ballast or transformer needed. My has a thermostat for the fan included in the circuitry, but that's it. All metal halides that I know of need a ballast=$$$.

Keep in mind that this is a raw bulb with no integrated reflector. Mine sits in a housing with a small reflector dish under it.

Good luck!

DYS projector lumens

Dear fender4,
thank you. That is what I suspect. I found the following:
which gives you the comparison between diffent light bulb. e.g. and DYS some consumes 600watt and only produce 17000 lumens but and EVD consumes 400 and give you 15000 lumens. There is an EKD bulb which consumes 650w and give you 2000 lumens, but its life is only 25 hours. I was having a hard time to find out the lumens rating for an old DYS projector and I notice that it may not be proportional to the lumens rating of the bulb it uses because of its construction and if the bulb has a small point light source or that it is spread to a larger filament area. Can I say that a DYS projector would be close to a 4000 lumens projector or less than that because of its construction?

I found that the MH bulb requires 5 minute of warm up. Do they have a special electronic circuit to speed that up or to put it to standby mode?

I found a place selling OSRAM MH 575W for $89 (no auction required). Can you found cheaper than that?

Thanks, Joseph.
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