Laptop LCD Projector

Hello everyone.

I thought id start a project log on here so i can share my findings with this awesome community, have something i can look back on, maybe get a little advice, and also vent in case something goes terribly wrong. Please forgive my English, its my second language.

The laptop im using for this projector project is a Compaq 1200 with 128 mb of ram, 3 gb hard drive, dvd-rom, and 800 mhz. It plays DVDs fine, as long as the disk is in pretty good condition.

a little about this history of this laptop.

I got it from a friend for $200.00. It was a great deal and probably still is. It had a 10 gb hard drive, played DVDs, and had enough horsepower for everything else i needed.

One day i was at a friends house. I was at his door and it started to rain. So i thought that i should probably get going anyway so I run to my car and take off in my BMW... About 5 miles down, accelerating to about 55 mph I hear a soft clump, crash. I thought it was nothing until about 10 min later when I checked for the laptop. No where in my car and i suddenly realised what that sound was. I left my laptop sitting on my car roof.v :eek: Turning around i get back to where i heard the crash at a busy street... Park, run out in the rain grab the smashed laptop in the middle of the street and run back to the car. After beating the loose plastic back into place, and 3 days of drying it powered up without any problems. The HD and LCD were undamaged from the fall and crash.

Later the back light inverter blew because it overheated apparently, and i tossed the laptop in a corner for a while. I decided to revive it for my car pc. Driving over 60 miles every day for 6 years without a single ticket or wreck i thought it would be safe.

I tore the lcd off, flipped it around (so it always was exposed with the lid closed) and i had my dvd/sound system for my car. With a 15 inch LCD stuck on with Velcro above my dash playing DVDs, i drove 5 months without a wreck or police interest of any kind. At night it was brighter then oncoming cars with far lights on. People would drive along side and watch DVDs with me.

One day going home from work i hit a nasty bump. Blew 2 tires, and completely bent 2 rims going 70 mph. with some luck and maneuvering i avoided 2 cars and a large truck. Ouch. The CarPC was off since its such a short drive not worth booting. I decided after that to remove the CarPC at least for a while. I figured that its not worth me putting other peoples lives at risk, and maybe if the screen had not been up at all that incident would have never happened. :bawling:

A little later i decided to build a bumper for my car out of fiberglass.. So i built it out of cardboard and covered it with resin and reinforced it. Removed the cardboard, and i have my custom one of a kind bumper. Dose not look too bad at all so i keep it on to make people wonder what the hell it is...

I think you have to be a little crazy to attempt a DIY projector project this and i defiantly think i have what it takes.

In my next post ill talk about my first attempt at a projector.
 
Test Setup

Ok well i began to strip the LCD. Getting it apart was a bit of a challenge. Parts of it were snapped on, and it seemed to have a metallic frame glued on? I did get it taken apart but i ran into a small problem:

[IMGDEAD]http://www.notwhatyouthink.org/nemesis/prj/DSC04206.JPG[/IMGDEAD]

Its too short! Its made up of two panels and they block light so this wont do. I cut the ribbon, and took it to a local shop to have it extended. They wanted $35 labor and $5 for the part. In addition they didn't have the part and sent me out to go buy it for them. I did not return. That night i extended it myself.

[IMGDEAD]http://www.notwhatyouthink.org/nemesis/prj/DSC04329.JPG[/IMGDEAD]

It took about an hour to solder all the wires on. The connections were so fragile that i decided to pour a layer of glue onto it to keep them from breaking. Sounds sad but iv never done soldering that small and complex. Success, the LCD works perfectly.

My budget for this entire project is less then $100 so i could not go with a MH light source. I went with the second best thing Home Depot pointed me to. A 500 watt halogen work light for $9.00 or so.

[IMGDEAD]http://www.notwhatyouthink.org/nemesis/prj/DSC04330.JPG[/IMGDEAD]

Next was the lenses. I grabbed 2 page magnifiers from Office Depot. These were meant to be my test lenses and if they worked good enough i planned to keep them. Each was about $8.00.

I visited every local store i could think of looking for a projection lens of any kind. Not finding anything at all i used a large magnifying glass i had at home.

[IMGDEAD]http://www.notwhatyouthink.org/nemesis/prj/DSC04331.JPG[/IMGDEAD]


Throwing the LCD, Fresnel, fans, and light into this temporary box i built i got my first results. It was awful, blurry, and dark. I could only focus on a part of the screen. But it worked! Most text was unreadable, but i was excited that it worked and it was worth investing money in correct optics. I did try a 35mm camera lens but that didn't work well at all. I did get a picture on my arm the size of a slide.

The next day I logged onto ebay looking for an overhead projector for cheap. I found a few for $9.00 through $30.00 with an extra $40.00 for shipping. It would have ended up around $55.00 for an old projector, and that didn't seem like it was worth it for a few reasons.

1) lenses could be scratched
2) very old projectors lenses could be the wrong kind or deformed somehow
3) not sure if it was a triplet objective lens on any of them

I figured that if I'm going to spend money on this i may as well as get the right lenses, so i bought the lens kit from LumenLab. They shipped it the next day and I'm expecting them here on Tuesday. So far I'm very happy with my purchase from LumenLab, because i really hate snail mail delays.

As soon as i have $150.00 more to invest into this i plan to purchase the light kit from them too. It seems very complete and the price is better then i am able to find at stores. With what i hear is a great bulb too!

But for now this Halogen will have to do.

Tomorrow ill try to draw out the dimensions for the box. I'll have someone at Home Depot cut it out for me and start putting it together.
 

meusick

Member
2005-07-14 7:11 am
TX
i had same luck with my laptop.....someone spilled water in it....how bad was yours damaged......mine powers up but no pic.....im thinking bout testing the light ......i have an ibm thinkpad...you think i can use it in that project?......hope to see your final project:cool:
 
I got the lenses yesterday and spent all day playing with them and building boxes. But i am having a few problems.

First the cooling. The 500 watt halogen bulb is about 235mm away from the LCD. With a large office fan blowing on the highest setting at the LCD and lenses from a cold start, it took about 4 seconds for the LCD to loose color and overheat.

I guess halogen lights are way too hot.

I positioned the light 400mm from the LCD and it ran fine for 5 min without a fan.

Next i encountered some kind of interference problem? When the LCD was close to the light, the LCD would not function properly. Lines flickered, sometimes only half the screen would be shown. But right when you turn the lamp off, or turn it on and the light powers up the screen is fine. Maybe its still just the heat problem? Or something from the electronics attached to the work light.

I did get a clear picture but only in the center. For example when Windows XP boots it shows a blue screen that has Welcome printed in the center. Well the projection did have blue and the letters but only the center in a circle. The rest was dark. I guess its something with my optics. I'll work on it some more today.
 
only center lit

Sounds like a light path problem. You need to put the light source around 220 mm from the stronger fresnel, to match its focal length. That will put mostly parallel rays out the other side of the fresnel. If you move the lamp 400 mm from a 200 mm fl fresnel, it will give you a converging cone of light on the other side. That would only light the center of your LCD! Sound familiar?

Try using 220 mm from lamp to condensor fresnel (ridges toward LCD), 20 mm to LCD, 30 mm to field fresnel (ridges toward LCD), then around 330 mm more to the projection lens. This spacing should be about right for a 10 foot throw distance.

Change to a 250 Watt wide pin capsule Halogen lamp, for now. Home Depot has them for a few dollars, and they have a much smaller filament than a 300 or 500 Watt. Should also cut your heat problem in half, but the image will still be pretty yellow.

DIYprojector Company store has IR-reflecting glass starting at $12! This will solve your heat problem completely, and would be needed with a MH lamp, too:

http://www.diyprojectorcompany.com/...id=80&osCsid=fcb4f474a18dfb50f407eaf433403430

Big halogen lamps inject a lot of noise back into the power line. I would not be too surprised if they also radiate it. Maybe the 250 Watt would not cause so much interference.
 
Yeah, its interference from the lamp. I had the same exact problem when the back light inverter got too close to the LCD. It would form static and lines.

I looked up that light you mentioned and only found this:
bulb

hopefully that will take you to the correct page.
Its only 5,000 lumens and i don't think that will be enough.

The 500 watt halogen I'm using now is 9,500 lumens and advertises as "white light". It looks white enough to me so i don't think ill have problems with color temperatures. But I'm having doubts that's going to be enough lumens at the end.

Right now I'm playing with the idea of mounting the 500 watt halogen not [[======]] to the LCD but ( o ) and build a cone reflector around it to focus the light correctly.

I doubt that will work at all but worth a shot.

I put the Fresnel lenses together and got an ultra sharp image just to test. I really don't see the advantage of putting a Fresnel in front of the LCD. I don't trust a plastic Fresnel as much as i do a glass lens to project an actual image. I'll play with both designs and post my results.