Sawdust is made. Picture of box and lens carriage to follow. Here is a list of specs and the core layout. The box will be installed in a sofa table/sideboard where the cabinet would normally be. The table top is the projector top, scissor jacks will raise and lower the projector.

1. Samsung 15.4 WUXGA LCD (not stripped) $60 ebay
2. Dell 610 laptop 2GB mem, 2.0Ghz, terabyte PCMCIA raid 0+1 disassembled and ready to go. $15 ebay + accessories
3. 14" Bessler lens $5 ebay
4. 330/500 fl fresnel $16 BHLens
5. 600w MH with positive airflow reflector and 6.5K bulb $200 ebay
6. Hot mirror (not procured)
7. kite FS mirror $18 Anchor Optics
8. Stepper motors (5) no cost
9. PIC16F877 control circuit (spare parts around the house)
10. PIC12F675 temp feedback fan controller

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The box test fit with the LCD support. I cut slots so I can have a split or unsplit setup, and course adjustment of position. The LCD support is made using style and rail router bits with a 1/4" rabbit to fit in the slot. The bottom rail has a cutout for the lcd electrics.

And there is a fan sans controller at the moment. And a cut out 1" larger than the lens for 1/2" lens shift. One of the steppers is there for the lens shift.

This box is mdf because it will be housed in a nice piece of furniture and cannot be seen unless deployed for movie time enjoyment.


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Also if anyone wondered. The Dell 610 is 14.1" SXGA normally and is advertised to drive up to 1600x1200 external monitors. Well the Samsung works great at 1920x1200. Apparently the Radeon 320 has more to give than Dell let on.

Waiting to see more of your project.

While I am also on the path to build one, my understanding is that fresnel lens do warp at high temperature. So my question is whether the fresnel lens do expand under heat?

If it does, isn't it better to design the fresnel lens holder that allow some degree of expansion?

Thats my question.

Here's a similar build: Folded 1600 With Pro REDO: The Widowmaker
And barry_x2's Completed thread.
It's a shame the video disappeared - it was pretty cool watching that thing expose itself.

Good job!
I look forward to seeing the progress on this one.

Probably there is not enough heat to distort the plastic, acrylic is very stable, and the temp should not be above 100 degrees or the LCD will fail. Also I would think it would distort the image if it did. So heat removal is critical.

I don't want to have the fresnel or lcd move since this will be subject to vibration from the stepper motors and the audio system and that would affect the image.

In any case it is not shown but there is room for thin strips of foam around the lcd, which is placed back into its metal frame and put in the wood holder as pictured above. The fresnel has the same gap for foam without a wood frame. This will help minimize 'buzz' from the projector.

The barry_x2's design is very nice. I hadn't seem that before, thank you.

My table will be a simpler design, that I build, because that is the way I like to do it.

Okay. todays work. Focuser is coming together. This will be the carriage for lens shifting as well. It is loosely assembled and still needs the idler, belt and bevel gear for drive shaft to be mounted. The plate with countersunk holes is a running fit and the plate on the timing gear side is friction fit

Threaded inserts are in the friction fit plate and that is the plate that moves the lens when the threaded rod is rotated. The lens itself is primary structure so the threaded rod can be installed running fit with no slop. Backlash seems to be small and the lens moves with little stiction. I won't really know if it has precession when moving until I get the motor installed and running.


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Todays effort. Just a trolley at the bottom and waiting for glue to dry I also stained the box black.

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Circuit for temperature control. Has outputs for temp and fan speed to feed to computer and display on screen on request.


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I will try to recycle this old board I made in college. It was a 4 axis cnc foam cutting board but the wire heater section burned out. So maybe it can have a second life.

It has a parallel interface so I can use the computer to set focus and lens shift. Also the buttons you see allow manual control. Parallel interface excludes the use of Vista, but I am okay with that.

If it doesn't work out I have more parts...


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Not much done this weekend.

My wife doesn't like me to spend all day in the shop so I bring some of the work inside. I don't think she likes that either...

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I decided the outside would be piano black. So I have stained it today and will finish off with the seal coat and lacquer coat later.
The cutout is for a flip open door that has the computer mounted to it. It gives easy access to the keyboard and accessory ports and such.

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So here is the access panel installed. I am still working on the lacquer finish, it is a long process that takes 5 days of drying before I can sand and polish.

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This is how the laptop is mounted. I need to make a metal base for grounding the board and a support for the combo drive.

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Quick update. Fresnel's are installed and because the e-ballast was back ordered and won't ship until tomorrow I am on hold. However, I have managed to project images! I set up a 500w halogen and I could get an image from it. So I know it works!

E-ballast is due in tomorrow so I can finally finish this weekend. At least with the projector part.

Below I am assembling the FFC, which is simply push the pin into the small hole. Not real exciting. I do have one extra wire installed, can you guess which one it is?

Also since I couldn't gender change the extension cable and I did not want to try to populate the 0.2mm connector to the laptop motherboard I am making a female/female adapter board.

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Nice work! The electronics are very intriguing.

Thanks SupraGuy. I'll show more of the completed boards and hook up in another post. For now this is what I have.


Box on bar stools. I really need to get to work on the sofa table!

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Cold side setup. You can see the tray which supports both the triplet mount and the FS mirror. This setup makes it possible to focus from 8ft to 20ft PJ distance. Additionally the triplet can focus and shift relative to the mirror.

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Umm, HPS? Well because of the long range of focus and lens shifting it seems appropriate. What fits into the triplet is more than 1/3 the length of the bulb and the output of this particular one is 95000 lumens @ 6000K. So it is still bright projection. Also the pro reflector is able to shift on the T-track used for support. When the triplet is shifted sideways it does not dim the edges. This setup may be changed in the future...

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I will seal up the box with weather stripping and the air is forced through this automotive intake filter and a carbon filter on the outside, just for having black showing externally. Two 100 cfm fans will pull the air through the filter and across the lcd, down the fresnels and through to the hot side and out the bottom.

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Okay. Just for fun five 50 watt amps will be added for portable sound. My HOA decided they would like to use my PJ for a party and how could I refuse? I am adding these very nice amps to the system. (Similar to the Linkwitz reccomended amp) I already have two built and have parts for eight more (can't have too much). This is another power requirement, but I have room. I guess a p-strip will be required.


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i have never seen somone use a high pressure sodium
i am curious how well it will work
the problem with that particular blub is that it has such a long arc
your fres will be doing all the work of puting that light into an point small enough for the triplet
but mabey your on to something
nice job on the electronics . they look sweet

Well, the fresnel CAN'T make that arc small enough to fit in the triplet, so there is a lot of wasted light, but it does allow the horizontal lens shift... But if lens shift is the goal, I'd probably see if the lamp could be mounted vertically instead, which would allow for vertical lens shift for keystoning.

I probably would have chosen a different lamp, for my own use, with the arc on that being so long, it's going to make other things more difficult to manage.

Works regardless. Vertical is not an option since the bulb is too long to fit in the box, and really it depends on what is more useful to ME on whether vertical or horizontal shift is preferred. The bulb came with the ballast, which can also drive MH bulbs, so if I feel like redesigning the light engine I have the option. I am well aware of the attitudes about HPS on this forum and diyAudio.

I obeyed few of the rules here, I used a laptop and screen, I used HPS light source, I used a 330mm for light collection and paired a 500mm with a 355mm triplet and I made it vastly more complicated with electronic lens shifting and folded design, but somehow it works...

So my experience is:

1. A laptop works for me and really was easy with just the custom FPC to build. I could have done without the FPC if I did a straight through design, but the placement of the mirror eliminated that option.
2. For kicks I tried a 330mm fres with the triplet (for a close match) and as I had guessed it just didn't work. 500mm is perfect.
3. If I decide I need a longer throw with a smaller picture I can change to the 18" bessler with only an adjustment of the mirror/focusing sled required. An awkward zoom solution, but effective.


I will continue to update the progress and eventually figure out my camera settings for good screenshots.

My makeshift screen is bad but here are the pics from windows 7 desktop. It is backwards since W7 is PITA with my AMD X300 integrated video. BOO DELL for not using the spec board!

So the picture is colored as shown here. However....
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It appears bright as shown here. The only difference is exposure time. I really don't know how to correct to get the actual picture on "film". I think if anything it is lacking green.
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Cable Assembly:
Looks messy, but it works.

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Fan controller board. Also a bit messy.

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Been using it and making video adjustments. It an improvement. Little blurry in the corners, but the triplet is not in the best condition, coating seems to be patchy.


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