| Hey, I just started my new Projector - Click HERE for Original Thread |
| mistertrent |
Hey everyone,
I'm new to this, and I am a noob, but hey, i've read a lot of stuff on here... and I am so impressed, and I am so excited.
I had an AOpen F50C, 15 Inch, 1024x768 75hz, 25ms Response Time, 300:1 ratio, Monitor sitting on my desk for quite some time, being used as an optional second desktop on occasion when i'm working to whack some DVD on while I procrastinate... so after reading about all the projector stuff, I stripped it down last night, in preperation for a 15Inch LCD Projector Project.
I'd love it if anyone on here could assist me with decision about my project as I progress through the stages, just incase i'm really stupid and stuff something up completely... So, I have a picture here of my Stripped down Panel ...
First question for the project.
I have seen 'Overhead Projectors' come with Fresnels... would it be in any way feasible to actually obtain a few of these of the focal lenght is known, and use them, instead of obtaining fresnels from places such as lumenlab, or surplusshed or wherever fresnels are obtained... because i'm in Australia, and I have absolutely no idea where to source a fresnel apart from an overhead projector supply store.
Second question for the project.
You'll notice in the attached picture, the PCB is folded back behind the LCD screen, and the cable attaching the 2 sides of the LCD Side Strips, is very short... I have read about this being an issue, because it will shield some light from getting the LCD... what are my chances of going to some local store and saying 'Extend this cable please?
Thanks in advance for anyones assistance.
Regards, Michael |
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| wylie-c |
| That has exactly the same setup as my Viewsonic VE500. I haven't extended mine yet, so what I've done is created a custom resolution with Powerstrip and have it running at 1024x488, and the image slightly compressed lengthwise. This lets me shrink the whole Windows desktop to fit between the pcb's. |
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| mistertrent |
I'm going to have to check that out... one side of the FFC is permanently attached to the bottom panel, the other side is a slot in with a clip job... dunno what its called, but it looks like it would be really tricky to extend, doh.
I went out today looking for Fresnels and Triplets and Ballasts and all... but noone told me it was a public holiday,... so back out again tomorrow, to do what I was going to do today.
My current plan is the 2 x Fresnels either side of the LCD, a MH400U and an electronic Ballast, and a Triplet Lense. |
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| Guy Grotke |
I'm starting mine, too. I just stripped a 15" LCD monitor panel with a side PCB and a top PCB behind the backlight, connected with a short FFC. (Sounds like yours.) I've picked up a few things by reading the 1000s of posts here and also places like diyBuilderGroup and lumenlabs. (You can buy very cheap extender cables for your FFC from either place.)
The UHI-S25DD or UHI-S400DD HPS-replacement MH bulbs have the very best Color Rendering Index (85) and color temp (5200K). They run off an HPS ballast, since they are designed to replace HPS bulbs with nicer light. You can order them from atlantalightbulb.com. More expensive than some others, but they last 15-20,000 hours! They also have a narrow tube bulb, so they can be used with a small spherical reflector. If spaced correctly, this will double the effective output! That's why I am using the 250W version. (But I am also making a pretty small image.)
Do some experiments with your fresnels: Some panels do not have very good viewing angles, so one below & one above works better (ie. viewing angle = 0). Some panels are more tolerant, so then you can put both fresnels together on the light-source side (clearer image).
Don't forget to divert IR & UV: You can buy heat mirror or experiment with a water-filled IR absorber. Another option is to cough up the money for a piece of cold mirror to bounce your light off. UV filtering can be from a mylar sheet UV filter or lexan with a UV coating. Don't skip this: UV will kill your LCD panel.
I don't think you can go wrong with a triplet (eg. $29 USD), but my projector is only doing 15" to 95" magnification from 14 feet, so I need a 570 mm fl lens. I'm going to see if a very cheap DCX singlet will work, since the chromatic aberration may not be visible at the low magnification.
Don't forget to post result pics! :D |
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| ancorp |
A dcx will definately an excellently blurry image :D.
Ive experimented with many lenses, and a dcx will give you are very bad image. The best singlet would be a positive mensicus, looks like this ((.
With a dcx, the image will not focus on the edges and center at the same time, will be warped into a circle, and have terrible light abbreviations. Get a triplet! Get the one thats 135mm in diameter with 450mm effective focal lenght. I got mine for 9.99, and I got a focusing mount with a handle and a front surface mount and a lightsource and reflector, and so on, with it too. I got it all from an old Opaque projector on ebay. The lens seems identical to the one at diylabs. |
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| ScottK |
Yoh Michael,
Here's where you can get parts for your pj in Australia.
1. FFC from Squirrel (Sydney) on Lumenlab.
2. 400W HQI-TS lamp + coil ballast, etc, from Taipan (Gosford) on Lumenlab. You won't find a cheaper price (new). I'm using it myself. His order form is here:
http://ww5.aitsafe.com/cf/add.cfm?u...=185.00&return=
3. For all the Lumenlab stuff, Terminal (Sydney) is in the process of setting up a shop here, and will be cheaper (on postage) than if you buy direct from the US.
Cheers,
Scott. |
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| Guy Grotke |
If I could buy a big 570 mm fl triplet (or even just an achromatic doublet) for $29, I would do it in a second. Unfortunately, I have not found anything close to that. I can get a 450 mm fl triplet for $200 USD, but that would not really fit my media room dimensions.
I have tried a little bit of experimentation with simple lenses (and I am getting several more from surplus shack tomorrow). In particular, I am getting a 200 mm fl DCX and a -308 mm fl DCV. If the DCV turns out to be flint glass, then this proportion together should be 570 mm fl and pretty close to the optimal achromatic ratio.
One experiment I tried used a 330 mm fl DCX projecting a 4 inch flat reticle about 10 feet to give a 4 foot image. The image looked very sharp and uniform, and the chromatic aberration was not discernable from 10 feet away. This is about 12X magnification. I think that chromatic aberration is less of a problem with less magnification (flatter lenses), so the 6.3X magnification target for my projector may be reachable with a singlet or a diy "doublet" pair. |
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