So, here I am again (or is it again again?) about to begin on my journey to building a high definition (720p) capable projector. It will be connected solely to my HTPC. My criteria for the projector is as follows:

Vertical folded design.
17" LCD must have DVI input, 1280x1024, 450:1 + CR, 16ms - RT, easy strip, easy AG removal, little to no FFC issues and preferably cheap. Must be capable of displaying DVD quality video, HD TV (tuner will be bought for the HTPC), and the latest batch of PC games, maybe even some XBOX360 or PS3 action. Suggestions??
Ideal projection size somewhere in the range of 100"+, I already have the blackout cloth I plan to use as a screen.
Unsplit fresnels, ie. no keystoning will be required.
FS mirror placed close to triplet (I understand there are some precision issues that I may have to fight with)
Powered focusing mechanism
I already have a light source(see list of accumulated parts), for which I plan to build some sort of light box/chamber/tunnel.
I plan to use 2 ideas for the cooling of this box. The first idea being a convective cooling solution for the light box, similar to what Punisher is doing in P-Cubed. In a second chamber I plan to use Dazzzla's cooling solution for the LCD (the whole S design). Overkill, yes. I'm not taking any chances here. Ohh, I'll probably get some evercools or something like that (suggestions).

Diagrams to follow.... eventually.

My accumulated parts so far:
LL 400w S400DD MH bulb, mogul base, elec. ballast
LL 120V Wiring kit
LL UV filter
250W PC PSU
Blackout cloth, 2 large sheets (don't have dimensions with me right now)
1 fried LCD (Samsung 515N to be replaced with... suggestions??)

Parts I'd like to accumulate:
LL Pro Lens Kit (fresnels, PRO triplet)
Tempered glass
FS Mirror
Some type of reflector, probably PRO from LL
5V Electric motor (Powered focus assembly probably, though not in stone just yet)
17" LCD ()
Building materials

This being my second build (improper cooling fried my LCD on the first converted OHP build), I plan to take my time. I've given myself a 12 month completion time, though I probably won't need it all.

I think I've got a layout for the box, and some simple diagrams for each of the little subsystems within it. I've pretty much decided I'm going to get the LL Pro kit and cut the fresnels to size. I actually already own the standard triplet, but I want to go long throw for this one. As mentioned I have an LL 400w S400DD MH bulb (which has been sitting around untested for months and months now) and the elec. ballast to match. I do not plan on using a condenser, but I will use a reflector (probably PRO). I havn't settled on a light box design yet, and am open to any suggestions. Others have done some really cool things with their light box, I'd like to either do something original, or just steal somebody else's idea.

So, what I need now is a damn good LCD for this project. Anybody have some suggestions?? High light transmission (8% +) would be a big plus.

Dave

So, here's a quick diagram of the LCD cooling solution. Once again, idea stolen from Dazzzla's plog and slightly modified.

Click to view attachment

More to come.

Dave

Here's a basic idea of what I want to do with the bottom of the box. This is looking at it from the front, so as you see, the base will be fairly wide to accomodate the upwards blowing fans on the one side. Air intakes on the right side should provide cooling for the LCD, Lexan and light box. I am hoping that the ballast will be able to stay cool on it's own being positioned directly underneath the fan.

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Here's the basic idea behind the box I'll be building, nothing pretty. In fact, it's pretty funny looking. the one on the right is probably the one that'll get built, since the one on the left doesn't take into account the bulge I'll need for my fans to vent vertically. The triplet will be on the right side of the box, from the perspective the pictures are drawn in.

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On second thought, this is probably the better design - smaller footprint. The only problem here is that I've got all kinds of angles... It's gonna take a very thorough full size layout to make sure I don't mess this up.

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Sounding good,DaveT3000
Like the plan,the cooling looks like it should be pretty effective.
I would advise you away from the evercools,(just my opinion).They can be prone to "whining" under stress.
A couple of 120mm pc fans should do you niceley.
I think Supra's lcd has proved to be the most transmissive so far,and DAZZLA has just picked one up too,it may be worth waiting to see what transmission figures he gets from his.
As for the enclosure,it looks it it should work very niceley,I like the last diagram,but as you say,those curves look a bit daunting,but if you have given yourself a year,why not give it a go?!
Whatever you decide,good luck.
Cheers P

This is really similar to the design idea I have now, except instead of having a tapered box with an extra bit tacked on for the exhaust, I'm thinking of keeping the box square and having an enclosed "chimney" in the back of the box. It'll just be a separate chamber the width and height of the box about an inch thick that the "exhausts" from the compartments being cooled will feed into. I'll see if I can get a simple drawing whipped up and posted in my plog.

So, I've been thinking some more about the monitor. I really like the idea of going widescreen for this PJ, which for a 17" panel yields a resolution of 1280x768 - capable of 720p through my HTPC (I'm assuming my video card will handle the minor resolution difference). However, a standard 17" has a resolution of 1280x1024 - why throw away all those extra pixels? I could just let the video card again convert the signal to 720p when needed and otherwize I have the added bonus of the better resolution.

Then I started looking at 19" panels for the widescreen. At 1440x900, this would make for a striking widescreen when blown up to 100", and the prices aren't really that bad (not that great either).

This leads me to my question. The 17" widescreen panels are listed as having a 17" viewing area, but with fewer pixels, does this imply that I'd be dealing with larger pixels?? The same question would apply for 19"'s aswell. I hope this makes sense.

Dave

Hey Dave there have been a few users who have tried out the 19" lcd but the general conclusion seems to be just to go with the 17". Even though there isn't much of a price difference these days you are sure to get the best use of the fresnel kitt with your 17" and I'm sure you've seen the results from a 17"pj at 720p it blows my 15" away. Just get teh best 17" you can and you will be more than happy.

Thnx for the input. I've spent the last hour or so looking for monitors that meet the specs I want and I think this guy may be the best one:

http://www.canadacomputers.com/index.php?d...8405&cid=MT.899

Samsung 740B, 1280x1024, 8ms, 600:1, DVI. For $260 CAD new, I think this is a good price too (I live in Toronto). Now I have to search the PLOGS to see if anyone has already tried using this thing. I think others have used the 730B, but I don't know what differences the 740 may have introduced.

I think I'm just going to have to accept that I may have to deal with FFC/AG removal issues - but hopefully they'll be minimal.

Dave

Hey Dave,you may have struck lcd heaven!
DAZZLA and Supraguy are using a Samsung 740N,which is the best transmission lcd we have found so far.I am not sure what the difference is between the B and N models,hopefully not much!!
Cheers P

Pun, you're right!!!

I've browsed their plogs and AG removal looks easy enough (though some had the polariser come off with the AG when they stripped) and no FFC issues. The 8.5% transmission is just phenomenal.

At first glance the only difference between the N and the B is that the B accepts a digital signal . Hopefully everything else will be the same.

With any luck I can track down one of these things at some cheap local PC shop.

Dave

Nice!
I have been looking for one in the UK for a few months,but they are still around the £200 mark here!
I have a panel to use for now,but am definateley looking to get one as a future upgrade.
Hope you find one.
Cheers P

I have a question. Does anybody see anything wrong this?

Click to view attachment

The idea is that the fresnels are larger than the LCD with the idea of getting more light through the LCD to the triplet. I think the angle that the light travels through the LCD is constant and independent of the its distance to the closest fresnel. So the angle of the light passing through the LCD shouldn't be an issue. Maybe other reflections since the LCD will be more exposed to stray light?

That is basically what supraguy was doing... by maximizing the entire fresnel you capture more light and placing the LCD in the area of the light cone where it is just larger than the viewable area of the LCD, maximizes the lumen output of the PJ. (In his case he was actually moving the LCD to focus the image, not sure of your setup) BUT... everything comes at a cost... in this case the cost of high lumen output was noticeably dark corners (low ROX number), he ended up moving the LCD futher back in the ligth cone, so more light was wasted (ie. lower lumen output), but the corners got brighter... he found his "happy medium" at around 250 lumens or so (I don't remember the exact figure)... i'm pretty sure he gave some numbers for his setups so you should check his plog if you haven't already.

neat design you have, it will be nice to see the finished product.

cheers,
gs

Thnx gadget, I can understand the dimmer corners (or atleast the sensation that the corners are dimmer). Altough a lot of light would pass through the corners, since so much more would pass through the center it would seem like they are darker than they are. I had thought about what you mentioned Supraguy had finally settled on. If I bring the LCD closer to the huge frenels then I'll waste some of the light, but the light that does go through should be much more evenly dispersed over the area of the panel. I'll have to look at his PLOG at little more thoroughly.

On another note, I'm still trying to find a box design that I'm satisfied with. Here is one that I think is probably a bit better than the last box design I posted.

Click to view attachment

The only problem with this box is it begs for me to vent my 2 chambers on opposite sides. So, I came up with these two alternatives to my original cooling solution:

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Having looked at them, neither seems quite as efficient as the original S. The first one has me venting the LCD chamber exhaust towards the floor. I maintained the light chamber verting upwards as I figure that's where convection will play the strongest role.

In the second picture I tried to get them both venting vertically, but it means having the fan on the right fairly close to the LCD. Also, the air running over the LCD will have already been somewhat heated.

Not quite satified with any of this, I cranked out one more box design that would allow me to incorporate my original cooling solution.

Click to view attachment

I guess this is the 'one', for now...

Dave

So, I was up all night last night with a case of projector induced insomnia thinking about this box design and cooling solution. I've now decided to divide the case into 3 compartments with the purpose of cooling each major component independently.

It's a little tricky to decifer this diagram, so I'll explain thoroughly. While everything is rectangular, try to imagine cylinders instead (It's hard enough drawing in 3D in paint using rectangles, I can't imagine trying to do this with any curves). I'll probably use the same type of ducts(sp?) found lining the ceiling of your basement... Here's the idea.

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For starters there are 3 cooling columns which vent vertically at the rear of the PJ.

Column 1: The ballast will be placed in the middle of this column. Intake is at the bottom, a single fan will be placed at the top, venting vertically.

Column 2: This column will vent the air from the light box (5), which will intake from either side of the projector. The light box itself will need to have an opening on the top. So this column will also serve to vent any air in the enclosure not found with any of the cooling columns.

Column 3: This column will vent any air from the LCD, fresnels, and lexan module. It will be sealed off to the rest of the enclosure. I have not drawn the main intake for this one (which will be a slot on the side of the PJ right next to the LCD). Looking at column 4, you will see where the air that has already traveled across the LCD, fresnels and Lexan will make it's way into column 3.

Column 4: Connected to the LCD module, allows air to travel out to column 3.

Light Box 5: The light box will draw air from either side, it's connetion to column 2 will be right at the center of the bulb.

That's it. I'll try to get a pic posted of what I plan to do with the LCD module. Since I no longer plan to vent this directly out of the inclosure, it will need to be reorganized.

Dave

I've been trying to figure a way around a little problem.

Since I've decided to go with a 17" panel with a 4:3 (1280x1024) resolution I can't help but hate that watching DVDs in 16:9 will mean two horizontal bands of my LCD trying to do black. Compounding the problem will be the screen. I want to have a screen with a dark band outlining my projection (I understand this tricks the eye somewhat into thinking greater brightness in the image).

To eliminate the two LCD black bands during movie watching I'd like to implement two 'blockers' (absorbing, not reflecting) into the triplet casing. I imagine I could control the lowering of a top blocker and the raising of a bottom blocker by rotating some sort of knob on the outside of the enclosure. So, playing games, browsing internet, watching TV I leave the blockers open. When I decide to switch to widescreen I can simply rotate the knob until enough of the picture has been 'unprojected'.

To have the dark frame around both the 4:3 and 16:9 projections I'll somehow need to be able to move dark bands at the top and bottom - the sides obviously wouldn't need to be moved. The bottom band is easy. All I have to do is create the band (somehow - paint? painted wood? wooded paint?) along the bottom of my roll down screen. Roll up until properly positioned. But the top band.... I don't know.

Any thoughts??

You probably want to do something like this

With an adjustable dark matte background like that it will make the triplet mounted mast unnecessary... the area's that don't show up quite black will look very black as the black fabric will absorb any light.

cheers,
gs

Perfect... I hadn't thought about fabric absorbing the light hitting the screen. It looks like Sepultura did a pretty nice job with that screen of his. Doesn't look all that simple though, I guess I've got my work cut out for me.

Thanks for the pointer Gadget.

Dave

I think I've finally got it (and in 3D too)

Click to view attachment

Maybe it's a little hard to orient yourself in this thing... but here's how I see it.

There are 4 intakes (marked 1, 6, 7 and just below 3).

The LCD cooling path has air taken in at 1, passed over the LCD, rerouted through 2, passed over the field fresnel, rerouted through 3, passed over the lexan (and under the collimating fresnel), collected through 4 and finally sucked out through 5. This is the S pattern that I think I stole from DAZZLA. This area of the cooling will be sealed off from the compartment below by the sheet of lexan.

The light and ballast cooling path is simpler. Intake through 6, 7, and slot just below 3 (I want air to run along the underside of the lexan). Hopefully the air will pass over the light box (8) and ballast (9 - I may have to move the ballast) and will be sucked out through vents 10 and 11.

Each of the vents should have it's own 120mm fan or something similar.

I decided against any of the other ideas I was throwing around because they wern't letting me use convection in any way and was leading to complete overkill.

I've gotten closer in determining the box dimensions. I now expect the width to be that of the uncut PRO fresnels plus a little extra on each side for mounting purposes.

Maybe I can start building the fresnel mounts soon.

Dave

I've always thought that spring loaded curtain rods would work well too (if you can find them long enough).. one on the top, one on the bottom rolled with black cloth. Just manually put them inposition to set the screen area you want... Not nearly as fancy as Sepultura's setup, but it'd get the job done...

gs

yeah thats lloks like a good alternative to what im doing i have to try to figure out how to incorperate it in my desgin. I may try push - pull method.

I've finally started to get some figures into my design.
Here are two more diagrams (I forgot to include the lexan sheet in these - it will go probably about 30-40mm beneath the collector fresnel).

Click to view attachment Click to view attachment

I've gone rectangular again (except at the back and top of the PJ) because I plan to build a shelving unit around the box which should allow me to set the appropriate height and house all of my other entertainment bits and pieces.

The PJ will be about 12' from the screen which gives me a 107" image. Using the focal calc this puts the LCD ~580mm from the back of the triplet.

The ray trace is from the outside of the uncut PRO fresnels and is therefor a sort of worst case scenario. Once the fresnels are mounted, about 10mm at the edges will probably be lost.

Part of the reason I've made the box so much bigger than it needs to be is that I'd like to be able to upgrade and adjust this PJ easily. I expect a 19" panel with an astounding resolution will make it's way onto the market in the coming years and being able to just 'drop' it in would be nice.

I still havn't decided where to put the ballast, what my light box should look like and what I'm going to do about mounting the triplet and focusing mech.

EDIT: Updated diagrams

So, I've got two more diagrams specifing what kind of play I expect to build into the triplet mount.

I plan to project a 107" image from a distance of 12', so about 580mm is required between LCD and triplet.
From here I'd like to be able to project a 200" max image and a 80" min image (obviously requiring a change in the PJ to screen distance). So the triplet will have a backwards travel of about 38mm and a forwards travel of 46mm to accomodate no only these max and mins but also to allow for raising the LCD by another 20mm or so (I am more concerned about being able to project a 80" than a 200" in case brightness becomes an issue).

Click to view attachmentClick to view attachment

Dave

Looking good Dave it's better to have extra space just in case. The design has an interesting shape as well getting away from the coffin shape is alwasys a positive Have you started practicing your woodworking skills yet?

DM

DarkMeat,, my 1st was the traditional (horizontal) coffin. You should have seen this thing. It was made out of mdf and I assembled it with screws and metal joints. It was a mess - the alignment was all off and the box was too short so I had to make my 'focusing box' extra long so that it stuck way out... But I didn't care, I had a big screen... until it died.

I guess this should explain why I'm going so far to make sure this one is very well designed and I take my time to build. I plan to go the mdf route again, though this time with glue, filler and lots of sanding. This box probably won't be pretty the way some people's boxes are, but it'll be clean, cool and easily adjustable and expandable. I'm hoping once people become more comfortable with condensors to get one in here.

Yes I have gotten a little more comfortable with wood over the past little while. I've put in some shelves (cutting, sanding) and I've put together a few 'custom' mdf desks in the last year so I think I'm up to the task. The more daunting wood work will come when I try to build the entertainment tower I plan to house this contraption in...

In the mean time, gotta keep at these paint drawings. Maybe I'll try to conquer Google SketchUp..

Thnx for the encouragement.

Dave

For my own reference:

Dazzla's S fresnel and LCD mounts: http://www.lumenlab.com/forums/index.php?s...pic=8388&st=200

where (usign a 330mm collimator)

Arc to Plano=17mm,
Plano to rear fresnel=285mm
Fresnel gap=11mm
Front fresnel to LCD=28mm
LCD to rear of triplet= 534mm

Click to view attachment

Threaded rod for adjustability... Is there any other way???

Well, now that I have a general layout for the box I've moved on to designing the light box/gate/tunnel.

As I try to handle these details I realize how much I appreciate the PLOGS of some of the talented builders before me.

With that said, I think I'd like my light box to be a tunnel ala Pun15er's P-Cubed light tunnel... With a few differences. I choose his design because it seems fairly easy to construct while at the same time handling a lot of the wasted light (nobody wants light bouncing all over their enclosure).

Starting with a sheet of tin (or some other metal), I will roll it up into a cylinder. One of the ends will remain open to the rest of the enclosure, while the other end with the bulb mount and will be sealed. An opening in the column will be cut at the top to allow light to escape towards the collimator fresnel.

The plan is that as the hot air rises out of the hole cut for the light, air will be sucked in through the one open end. No dedicated fan here as I am not terribly concerned with cooling this bulb as I understand they don't mind their own heat, and convection should move the air fairly well. The heat that rises out will be swept up by the two 120mm fans cooling the bottom of the enclosure.

That's the plan, diagrams to follow.

Dave

As promised, here's the diagram:

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I plan on making the entire tunnel 3D adjustable within the box, and the reflector 3D adjustable within the tunnel... That should take care of any possible alignment issues.

Dave

More ideas for the light tunnel...

...thinking outloud...

I'm worried about the hot air around the bulb 'overflowing' out the open end of the tunnel...
Not to mention, light spilling out that same end.
I guess I could slot the tunnel opening, get two birds stoned at once??
There's not really any reason for this to be a cylinder..
There's got to be a better shape to let that hot air flow out of the tunnel more effectively.
Perhaps a cone with an open top. To it's side attach a cylinder that feeds the cool air.

I will call this beast cyli-cone.

Diagrams coming...

Anybody got better light box ideas?? I've got lots of space in this PJ so I could really do anything here..

Dave

I've been toying with different light box shapes for a while, and here's the shape I've settled on (for the moment). I'm going to call it something like a "light chimney." It may be overkill, but here's what I have so far... (low-res/crappy version for now, high-res/good version to come to my Plog soon...)



Yellow - Air intake path
Purple - Air output path
Thick green - Internal air intake
Thick dark blue - Fans (120mm and 80mm)
Thick red - Chimney opening (will have to have some kind of vent thing to keep light from escaping)
Light blue - Bulb (with pretty light lines)
Dark red - Light box window (no lightbox should be without one)

Bow down to my mad 'leet paint skillz!! (original black wireframe not made in paint)

In case my image isn't there for some reason, more of less it's an upside-down "T" with a chimney sticking up and 2 fans bringing in cool air from the sides. I'm also planning on putting a couple fans on the bottom to move a little air through the projector box itself. I plan to put my ballast right under the two internal fans.

Hirudin, that is almost exactly what I had in mind. Except I'm not so sure I will need those fans: I expect the heat to rise fairly well on it's own.

Here's my diagram.

Click to view attachment

I saw no reason to only have one end of this tunnel open, so I cut the opening size in half, and let the air flow from each end in, up and out. This should hopefully minimize some of the light lost out of the sides. Heat should also escape a little more efficiently with a little more of a chimney. No dimensions just yet, once I measure the bulb I probably get some numbers into this or a similar diagram.

Here's yet another diagram. This is how I plan to mount the light tunnel. It will sit inside of this rectangle. This contraption will be able to adjust vertically and in the Y axis. Adjustability for the X axis will involve moving the light tunnel itself along inside the bracket.

The construction of this thing will probably involve 1/2" mdf and a couple of 90' brackets with long holes for the screws to allow for the necessary adjustability.

Click to view attachment

Dave

Are the bottoms of the L brackets going to be fully supported along their lengths? If not, that much MDF plus the light box might cause some bending.

Hmmm, the idea is that the entire bottom of the L-bracket is in contact with the bottom of the PJ enclosure.

I would think the most vulnerable bending position for the brackets will be when the box is at full height. However, any non vertical forces should be felt by opposing brackets in equal and opposite magnitude. I expect any one bracket's desire to bend to be neutralized by the opposite bracket's desire to bend in the opposite direction. So any non-vertical forces should be neutralized, and all of the vertical force should be evenly distributed among the four brackets, most of it directly where the vertical part of the bracket meets the horizontal part (ie, at the corners of the 'box').

In fact, I don't think I even need to screw this 'box' into the bottom of the PJ enclosure. I expect it to be able to stand on it's own, just as your kitchen table does.

edit: I can see how enough weight could still bend the brackets - they aren't directly under the center of mass. But I don't think the 5-8lbs this box will weigh is going to be enough to exert that kind of force. Especially if the brackets are secured to the bottom of the PJ enclosure.

Does this make sense??

Dave

It makes perfect sense. If it's going to be on the bottom of the enclosure, I don't think it will bend. The way I'm designing my enclosure, I tend to think of everything, including the light box, being suspended, so that was my first thought when I saw your design, but it turned out not to be the case. I was concerned that the L brackets might be mounting to a rail or something, but if they're on the bottom, you shouldn't have any problems.

Here's where things start to get a little tricky.

I would like to have the ability to adjust, while the projector is running, the height of the light box and LCD. In combination with the adjustability of the triplet, this should allow me to find the brightest and most evenly lit image without having the need to turn the PJ on and off to access little screws.

I think I know what to do for the light box - though not really. I plan on having an external knob that operates similarly to a car jack (I'm no mechanical engineer), but I don't know what I need to do this or how really.

As for the LCD... I have no idea.

Suggestions are all welcome (and probably needed at this point).

Dave

I've figured out two possibilities for the LCD vertical adjustment.

The first one is essentially 4 'jacks' similar to what I'd like to do for the light box adjustment (not what I have in the above diagram though). One at each corner, so I would have 4 knobs that I'd have to adjust in unison to ensure a flat panel - but I think it's doable. Then I was thinking maybe I could get away with only 2, and maybe use some drawer sliders for stability... Not sure.

The second idea is to use drawer sliders to keep the LCD tray on a vertical track and at each corner of the tray attach a cord. I would run each of the 4 cords vertically and then bring them together at a common point (outside the light cone). At that meeting point, I attach the cord to the knob on the exterior of the box. As I rotate the knob, the cords wrap around, raising the LCD. It could work, but again, not sure.

I think I've got the rest of the light tunnel adjustment figured out, I'll post the idea with diagrams when I get the chance.

Any thoughts??

Dave

I'll share an idea I've been playing with for a focusing mechanism. You might be able to adapt it or improve on it for your light box. I haven't even worked it all out yet, but here's an ugly drawing of the basic idea:

Click to view attachment

It's basically two bent levers connected on one end by a cross bar. You could use a threaded rod through the crossbar to move it up and down. The angled part of the levers would rest on the bottom of the enclosure and the ends would support the light box, which would ride on drawer sliders. Depending on how fancy you want to be, the angled part of the levers could ride in tracks or slots or the ends of the levers could be fixed to pivots on the light box. The levers could be made of metal or wood.

Now that I think about it, you could use a much simpler version. My idea has two levers because it's for moving the triplet, and there's one on each side to stay out of the light path. Since your mechanism would be below the lamp, you don't have to worry about that, so you could have a single lever going to the middle of the bottom of the light box.

I don't know if any of this is useful, but at least it might help spark some ideas.

That's interesting. I like the idea. Not sure how effectively I'll be able to implement it though.

I'm starting to think the ol' rack and pinion approach may be the easiest and most effective. I guess I've got to get down to the hardware store and see what I could work with.

Thnx for the idea.

Dave

As I described my idea in that last post, it started to seem less and less like something you could use, but I trudged on through, hoping it would at least be useful to someone.

Try this idea for a cable lift.
When you turn the take-up roller , the platform is raised. Tension springs below keep the cable tight.
Not shown are drawer slides for postioning. The light engine could be suspended from the lcd platform.

This lift system could be done with one cable on each side or one long cable for both sides.

Marco, this is something like what I was thinking and right now I'm leaning towards this type of design. Have you done something similar in your build?

I guess this would put the adjustment knob at the top of the enclosure. But I guess with enough tulleys I could put it anywhere..

I don't think I'll be atttaching the light box, I also won't be attaching the fresnels. The fresnels will be the only 'projection related' item to stay fixed. The light tunnel will be able to move independently of the LCD.

I've realized that being able to move the LCD and the triplet will allow me to slightly adjust the size of the projected picture - atleast it would seem so.

So I think I'm gonna do it. This is it... Now I think I need to build the fresnels' holder, as it will be the standard for both the width and lenght of this box.

Dave

I have'nt started my build yet, in the designing staged. I also plan on a vertical projector.

Small update today... As an aside - I havn't updated my plog for a while only to find it buried 3 pages deep. I guess there are a lot of people building PJ's these days.

So, I was trying to figure out how I was going to raise and lower my light box via a knob at the side of the box, while the PJ is running..

I was thinking about something like this initially:

Click to view attachment

The idea is as you rotate the knob, the slider gets pushed along a track (shown by the 2 almost vertical rectangles) and rises. The light box would rest on the top of the slider, so as it raised, so did the light box. This is just the basic idea... but I won't be using this.

Instead, I'm going the Scissor jack route, or some other type. I'm either going to buy one, or simply build it myself. Diagrams probably are going to get drawn for this, probably.

That's all for now.

Dave

Maybe I should have seen this coming, but I'm thinking about ditching this emormous PJ in favor of a far more portable Hami style mini PJ. The big daddy model will be far more appropriate once I graduate from school and can live in one place for more than 4 months.

After looking through the forums I've found a few very nice Hami PJs, and despite the 800x600 res. of the 8.4", it looks like I could blow it up nicely using the standard triplet I already own.

I would have to give up any dreams of DVI obviously, but it means I could have a nice small PJ, that would sit on (maybe under) a coffee table. This PJ would be far easier to build, and I already have almost all of the parts I need (except for the actual LCD).

I worry about FFC issues though.... Anybody know if these LCDs can be used without FFC extensions??

Time for more research... After all the time I spent figuring out my 17" I gonna throw it all away... Oh well, atleast I didn't spend any money...

Dave

yep you will need longer FFC's

Lots of Hami builds on Allinbox by the way,
Plog section here:
http://forum.aspect-geek.net/aspectgeek/Pr...ste_sujet-1.htm

Pics of finished PJ's on the home page
http://www.allinbox.com/

longer FFC replacements:
http://izzotek.com/achat/index.php?catid=17

Hope this helps

Thnx, looks like I've got (more) reading to do...

The question now becomes... Do I go with the 4:3 8" Hami, or the 'new' 16:9 9.2". The 4:3 is 800x600, while the 16:9 is 800x480 (or I guess 480p)...

I'd really like the widescreen, but why give up the extra 120x800 pixels??

I understand that smaller pixels generally mean more restrictive light transmission, so maybe the widescreen would result in a brighter picture (bigger and fewer pixels, so I assume smaller pixel size).

Once I figure this out, I'm ordering, designing, and building. I doubt I'll need the 12 months I originally gave myself.

Dave