So I stumbled across the idea of a DIY projector probably about a year ago now. But the instructions I found were way way way less official than what can be found here on lumenlabs. I actually went with the type of build that they used on tom's hardware guide which consists of a overhead projector with an LCD slapped on top of it. To my suprise, it works magnificently. And it's crazy cheap too. I managed to get my hands on a 3M 9800 overhead projector (http://www.touchboards.com/a3m/ohp9800.asp) on e-bay for about $60 and I bought a 10.6 LCD kit from Johnzo (thanks!) which was something like $200 when I bought it.


So I got all my OHP, my LDC, and my LCD controller. All I needed after that was some 1/2 inch foam board, some duct tape, a few screws, half of a 1/8th inch audio cable, a standing fan, and a europe to american coaxial input adapter.

first came the stripping of the LCD. Taking the metal rim and little neon lights out was no problem. Stripping the anti-glare was probably one of the more stressful things i've ever done. After a good soaking, the shiny back layer came up really easy. Then i went to take off whatever was in the front. This is what stressed me out. It's not that it was difficult to remove, but there was something about it that just made me uneasy (probably something about prying layers off a fragile and expensive LCD with a razor blade). After removing that first layer on the front side, I decided to check if there was another layer that wasn't the polarizer. I did another soaking and then had a friend hold a flashlight behind the screen as I started to peel up the corner of the next layer. I brought up maybe 1/16th of an inch of the corner when I realized that as I pulled it up, the image on the screen was dissapearing - that's when I realized I should stop because I was going to pull off the polarizer if I didn't. With one back layer and one front layer gone, I felt like I had removed enough, so it was onto assembling the box.

I used the 1/2 inch foam to make a frame/standoff for the LCD so it was not touching the top of the OHP and made sure there was enough space for airflow to get through. I then duct taped that down to the top of the projector. Then I screwed the LCD controller to another piece of foam which I then duct taped to the body of the projector and made sure that it wasn't going anywhere. After that I used my half of a 1/8th inch audio cable and soldered it to the audio output on the LCD controller board. And of course, to keep it cool, I put the standing fan next to it and used my best judgement to aim the airflow at the crack inbetween the screen and the LCD. And BAM, my first bootleg projector build.

As for a screen, I live in a college dorm where holes often appear in the walls after a long night of drinking. Keeping this in mind, I didn't want to spend a lot of money on a nice official screen. My solution: a 9 foot tall of brilliant white lighting paper. Fortunately my father works in the commercial production business, so getting my hands on this was easy and cheap ($15 for a 30 foot roll which is enough to make 3-4 screens). So I just duct taped a huge peice of this to the wall, not worrying about how big the screen size is actually going to be (because if I just cover the whole wall, I can't miss)

I fired it up, and everything was perfect... well... almost everything. During the stripping of the anti-glare layers I managed to do something strange to the LCD. Apparently I didn't do it smoothly enough because there were hundreds of little diagonal lines where I started and stopped during the 20 second stripping process. But i'm no perfectionist and the lines are barely visible on the projection. The one larger problem is that I bought my projector used to there's a large scratch-like thing on the top layer of it and it's a bit of an eyesore.

but all in all, it's a pretty freakin sweet $300 projector. Supports component in, vga in, HDMI in... I couldn't really ask for more for that price.

But now i'm starting to get idea's I'm thinking of replacing the top layer fresnel on the OHP and maybe even buying a LCD from Johnzo (assuming his new 12 inch screens work with the LCD controller I already have). Also one of the design flaws in my build is that there's so much light escaping. Because it's open faced, the whole room will get lit up by the projector being on. Also the EVD 36v 400w bulbs i've been using burn out in 20-50 hours which isn't very long considering they are costing between $7 and $10 a bulb. I can make them last up to 100 hours if I put the OHP on low light mode, but lets be serious people, the brighter, the better.

Well i'm at work right now, so I don't have any pictures at this moment, but as soon as I get home, i'll put some up.

I hope you guys enjoyed my essay =P

You'll eventually want to switch to a Metal Halide bulb and ballast as the OHP bulbs don't last very long (as you found out). When you get to that point, you'll probably want to build your own box to house it.

Here's a link to an older article on how to "Retrofit Your Overhead Projector" that you might (or might not) find helpful.

The LL forum won't let you search using a three-letter word. I find it easier to use Google for searching the LL site: site:lumenlab.com +OHP
You can add other keywords like "convert", "conversion", "retrofit", "metal halide" and the like.

Hahaha, you read my mind. While doing research on what kind of bulb I should get, and how the ballasts fit and such I came to the conclusion that if i'm going to put a new ballast in there, I might as well build a nice wooden case for the whole thing. Then I thought "if i'm going to build a wooden case, I might was well get new fresnels". And it looks like i'm pretty much going to be building up from scratch. The only thing(s) I plan to keep from the OHP is the triplet lens, and the nice sliding bar that it's attached to (hooray for easily manipulated focusing/resizing).

Well it looks like i'm gonna go and get my hands dirty i'll post back when it's done or when something goes terribly wrong.