I am very new here (as my post count shows only one) and I was hoping the community here could help me out a bit.
I have acquired a free 19" LCD screen and a free overhead projector and I would like to make them into some sort of projector for my computer.

This is where all the experienced folks come into play.

As you could probably guess the 19" monitor is too big for the viewing field (and compact fresnel lenses) of the overhead projector. As it happens, the screen is approximately 14.75" x 12" (that's a wonderful 4:3 format) and the viewable area of the overhead projector is 11.25" x 11.25".

Now, I've been trying to figure out the geometry behind all of this and found a few tools offered on this website (DAZZZLA's FocalCalc) but I would like to keep the "vertical" format to save space and the FocalCalc tool is set up for horizontal builds. The format, however, is not my largest concern. I was also trying to figure out how to mount the LCD within the plywood box while keeping the entire viewable area exposed.

This all started with some delusions of grandeur, but now that I've found this forum it seems like it could become a reality...with a little help, of course.

In short: I'm very new to this idea, and I need as many tips as I can get that don't involve buying anything new.

My components:
Overhead Projector: EIKI OHP-4100
Triplet Lens: 275mm-320mm
Bulbs: 82v 360W at ~4000 lumens

LCD Panel: LG Philips LM190E03-TLB1
Resolution: 1280x1024
Brightness: 300 (cd/m2)
Contrast: 700

(I have no idea what the Brightness and Contrast numbers mean, I just yanked them from a spec sheet)

If you can shed light on any of this, I would greatly appreciate it. Also, any tips are greatly appreciated.

-Clide

I am new here too, but I was under the impression that dazzzla's calculator was for a straight build (horizontal) and for folded designs using a mirror whether they be horizontal or vertical folds... but I could be wrong, don't go by me

Okay, a couple of points...

1. The focal calculator works for any kind of build, straight or folded.

2. Most OHPs have objective lenses with less than 330mm. Using a 19" LCD with this gives a VERY short throw.

3. Most OHP beds aren't nearly large enough for a 19" LCD.

However, the basic concept works.

If you must use the 19" LCD, I would count on having issues with the FOV. The LL Pro triplet can do it, but the less expensive Besseler lenses will have issues. The OHP lenses... Well, even if they CAN focus the whole screen (And I wouldn't want to count on it) the throw will be close to unusable.

So, one way or another it looks like you've got some money to spend, to get things the way that you want them to be.

Option 1: Toss the OHP. This makes the LCD the element that you're going to keep. You're looking at about $450-$550 with the Pro lens set, light set, and misc bits and pieces. You can save money on the lamp, and maybe look for a used pro lens, but that's a ballpark.

Option 2: Get a different LCD. A 19" LCD monitor is a nice one to keep and use as is. Johnzo1995 has a 10.9" WXGA LCD which will handle 720p. It has HDMI and component inputs on the controller which will allow you to connect it directly to your HD source, instead of having to use a computer, (though you can use a computer via VGA as well.) This can be used with the OHP with minimum modifications, and sells for (last I looked) $325.

The result will be a smaller overall box with a decent throw, and a reasonably cheap parts list.

You might not want to go this route, but...

Option 3: Use your existing 19" LCD with the OHP, but use Powerstrip (Google link) to shrink the active area of the LCD down enough to fit the OHP bed. You might lose resolution, but it's definitely an option. Not an option I would take, though.

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Below is a little information that I like to pass along to new members:

The best place to start is The Lumenlab PRO DIY Projector Guide V.3.

Once you have a grasp of the basics, you might want to peruse the pinned topics at the top of the Beginner's Forum. This is also where you should go to create your own threads when you have questions.

Then you can move on to the pinned topics of the DIY Video Projector Design forum and the FAQ section.

When you're ready, you'll need to decide what parts (LCD, Fresnels and triplet) you'll need. To do that, you can use the handy FocalCalc. FocalCalc will help you determine your enclosure measurements and will let you experiment with different parts before buying anything. This will also tell you how far from the screen your projector needs to be (throw distance).

When you start your build, you can create your own PLOG (Projector Log) to chart your progress and to ask questions about your particular build.

I've found that Google Sketchup is handy to use to design and visualize what your projector will look like. And best of all, there's a free version you can use. If you go to the Google 3D Warehouse and do a search for Lumenlab, you'll find that some members have uploaded parts that they have modeled so you can download them and use them in your own model.

A lot of the questions you might have probably have already been asked and answered several times. While most of us do not mind answering some of the same questions repeatedly, you might get more satisfaction in finding the answers yourself. Unfortunately, the built-in Search feature on most of these online forums is quite limited in what it can do. You might find it easier to search using Google using the "site" parameter. Below is an example:

Google search: site:lumenlab.com +OHP +"19" powerstrip

You can find other parameters by clicking the Google links in my signature.

You might run across a "quirk" when searching using Google, however. If you notice the thread looking "wonky" like this image, simply go up the the top right corner of the thread and click on Options and then Switch to: Standard.

I hope this gets you started on the road to your new obsession and I look forward to seeing your progress.