Hey guys,
Well I'm at it again. For my 3rd attempt, I will be building a projector for my uncle. This is the first time I am trying a folded projector so hopefully everything will turn out well. The projected image will be 130" Diag. and a throw of about 9.5 feet. I had to go with a shorter throw due to the size limitations of the room.

Parts

LCD
10.4" 1024x768 HDCP MST Controller HDMI, 2 component, 2 composite, tuner, S-Video, VGA

Optics
2 220 Fresnels
223 mm fl Precondensor
Pro Reflector
220fl Triplet (Needed for a shorter throw)
Mirror

Cooling
120mm Fan flows 107 cfm

Lighting
HQI Bulb 250watts, 93 CRI, 5k CTemp, 15,500 mean lumens, 163mm
250w Ballast ANSI S50

Screen
BOC

Here are some pictures from the 10.4 LCD. The 360(720p) via component, and an HD cable box (1080i) via component. I didn't have an HDMI cable to test that, however.
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Some more.........
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Ok guys I've got a question, or clarification. Along with the 220mm triplet i am using a 220mm field fresnel. So from the fresnel to the triplet will be about 210mm and from the LCD to the triplet will be about 240mm. So for a folded, is it 120mm from the LCD to the mirror, then another 120mm from the mirror to the triplet, obtaining the total 240mm?

Thanks

Yes, the total distance needs to sum up to 240mm. However, you don't have to split it evenly. You could place the mirror a lot closer to the triplet, with distances of 180mm and 60mm respectively, which would allow the mirror to be smaller. However you do it, just make sure you add up the distances.

Is their a formula for figuring mirror size based on how close it is to the triplet?

Hmmm, I don't know off the top of my head. If there is a formula to be worked out, it would be based on the distance from the fresnel, and not the triplet. If you think of the fresnel as being the base of a pyramid, the light that comes out of it will theoretically converge to a singe point at the focal point of the fresnel (220mm away in Swill01's case); the light would form the sides and tip of the pyramid. You could use regular math to determine the size of the intersecting rectangle if you 'cut' the pyramid of light with a piece of paper (with the paper parallel to the fresnel lense). Of course, this size is with the paper parallel to the fresnel, and the rectangle elongates when you turn the paper 45 degrees away from the fresnel. That is where the math gets fuzzy for me.

Sorry that I can't be of more help.

I'm pretty dang sure SupraGuy (and/or someone else?) posted a thumbnail formula somewhere. Some creative searching may very well uncover it. I'll have a shot sometime today at finding it if I remember.

Edit:

Here's one.

Thanks for the clarification Pirin.

Ok. another question
What do you guys think will work better with my 220mm triplet, a 220 or 317fl field fresnel? Before I was set on using the standard 220,317 fresnels, but I was talking to someone who said that the 317 field fresnel and 220 triplet weren't a good match, rather i needed a field fresnel with a closer fl to my triplet. So he suggested a 220fl field fresnel. Which do you guys think is better?

Again thanks for all the help, Im buying the wood tonight, just trying to nail down the distances.

OK, we're looking at the wiring and have a question about the 250W Venture Quad Tap HPS CWA Ballast Kit...... The ballast seems to have 4 different input voltages..... 277V, 240V, 208V, and 120V. Looking at the wiring, the 120V input lead is capped off, as well as the 208V, and 240V. The only open lead is the black 277V. Should the orange 120V be stripped and used as the input along with the common white lead and the black 277V lead be capped off?

I'm confused.

Thanks in advance for the help.

Since you live in North America, and use 120V, the answer is yes.

http://www.lumenlab.com/forums/index.php?s...st&p=262260

Thanks. Got everything wired just to test the bulb and everything looks good.

Click to view attachment

By my logic the light cone is the size of the LCD at a distance of 0 from the fresnel's optical centre, and has a size of 0 at the fresnel's focus, and decreases linearly from there. So an effective way of calculating it would be:

Mirror size = (LCD Size) x (focal length - distance from fresnel)/(focal length)

Note: this is the side of the mirror closer to the fresnel, as the light cone will be larger here.


In your case, if you label the distance from fresnel to mirror as X, the formula is:

mirror size = 10.4" x (220 - X)/ 220

Ok folks, Haven't updated in a while but have made some pretty good progress. I have everything wired, fresnel, LCD, front fresnel, controller board, and precondensor mounted however I have a problem. Last night decided to test fire to make sure I didn't rip the ribbon cables while installing the lcd, and while everything came up fine the image on the lcd was not upside down. The ribbon cables are on the bottom of the box. Its also not backwards but that is because I am using a mirror which will flip the image horizontally. So any ideas as to why this is happening? Faulty LCD or controller? I already checked the LCD menu to see if there was a setting to flip the image and there wasn't. Here is a picture of what I am seeing. Any help would be great.

I couldn't find the model of your LCD listed anywhere here.
It might be that your LCD is one of those few that has the PCB mounted at the bottom, instead of the top.