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Hardware

Homebrewed LCD Projectors 208

Posted by timothy from the depends-what-you-call-simple dept.
pseudofrog writes: "Seems the new thing to do may be to build your own LCD projector. For a couple hundred bucks, some guys are making projectors similar to the professional ones that cost thousands. And it looks pretty simple, too."
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Homebrewed LCD Projectors More

Homebrewed LCD Projectors

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  • Er.. I thought the bulbs alone that powered the projectors cost several hundred dollars? Unless the manufacturers ridiculously over charge for the bulbs, I don't see how an entire system that costs several hundred dollars could compare to a system in which the bulb alone cost that much.

    • Re:Cost of the bulbs? (Score:3, Interesting)

      by Anonymous Coward
      They're not the same kind of bulbs. These bulbs come from overhead projectors (like you see in schools) and tyically cost anywhere from $5 to $15 . The downside is they usually only last 75 to 150 hours.

      I got a dozen bulbs (4000 lumens) for my setup for about $75.

      • Maybe someone should build a custom enclosure with White LED's [slashdot.org]

        • Re:Cost of the bulbs? (Score:1)

          by Anonymous Coward
          An array of white LEDs may be brighter than incandescent tungsten filament lamps but (so far) it is still nothing compared to an arc lamp, which is basically what these are.
          • Considering that big arc lamps power most spotlights for big shows, those suckers can put out a heck of a lot of light. Of course, they also can damage your eyes if you're too close to them, but that's a minor detail. It's still a pretty cool concept, regardless. No doubt they are expensive, though, and I just can't see an LED array being able to even come close.
      • There is some reasons for the high bulb cost. As noted in other comments, heat is a killer to LCD's.
        The high lumen projectors have 3 things special about the bulbs. 1 is point light source. Light from a point can be focused with the mirror to get most of the light to the LCD's instead of scattering. (A mag light can be focuesd to a bright narrow beam. a flourescent tube can not focus tightly and is not useful for projectors). Porjector lamps are usualy manufactured as a prefocused assembly so it is user installable without a difficult alignment procedure.
        2 is a cold mirror. The light from the bulb has to hit a cold mirror reflector to get to the LCD's removing the IR component. This allows a higher power bulb to be used without killing the LCD's. The light from the arc does not directly go to the LCD. The end of the bulb with a terminal faces the LCD's shielding them from the IR output of the bulb. Cold mirrors are not inexpensive. Try buying one.
        3 is it is a discharge lamp. This produces more visable light over an incandecent lamp of the same power. Discharge lamps are usualy rated for 2000 hours instead of the typical 8-24 hours for a 3400 degree incandecent. They also have better daylight color tempeture (5600 degree typical) for better color so the pictures can provide a true rendition of the blue screen of death. ;-)
    • Unless the manufacturers ridiculously over charge for the bulbs...

      Bingo. LCD projector manufacturers know they are on the gravy train and they like it. Also, some projectors use regular Halogen bulbs, those are MUCH cheaper but the projectors themselves tend to be of low quality (and will only work in small rooms).
  • Well everything looks simple.

    • Re:Simple? (Score:3, Interesting)

      by Wavicle ( 181176 )
      Yeah, some of them too simple maybe. Like those plans that were scanned (about half way down the page)... If I'm reading those plans right, he has two 75-100 watt incandescent light bulbs in the box, but not behind the LCD projector - they are in front and to either side. I'm really confused how that is supposed to work. I've seen this sort of thing before from inexperienced people making those upside-down TV & Fresnel setups who think "If I have more light in the box, the image will be brighter" (yeah it will, but so will turning on the lights in the room - and it's obvious why you don't want that).

      Anyone got a clue on this? It looks to me like those incandescent bulbs would destroy the image. At the very least the light coming from those bulbs would have to make two trips through each LCD, so the color density would be off. Not to mention the fact that those light bulbs being off to the side would not tend to radiate light that the LCD monitor would direct out of the box. Looks like someone put a lot of work into the design, but it's wrong.
  • The coolest part about all of this is that in a few years time, the technology will be there so that the walls of your room are LCD/oLEDs and with the touch of a button you can make your walls have any wallpaper you want.

    Just think, you could have the Windows "Clouds" wallpaper all over your room! Imagine that! Gee, if that were my wallpaper, I know I'd feel like I was actually in the clouds.

    Hargun

    • Re:LCD/oLEDs (Score:5, Funny)

      by wirelessbuzzers ( 552513 ) on Sunday May 12, 2002 @09:11PM (#3507979)
      Just think, you could have the Windows "Clouds" wallpaper all over your room! Imagine that! Gee, if that were my wallpaper, I know I'd feel like I was actually in the clouds.

      Really? If I had the Windows "Clouds" wallpaper all over my room, I'd feel like I was in Hell!

      Moderation Totals: Flamebait=1, Troll=1, Total=2.

      • Re:LCD/oLEDs (Score:2, Funny)

        by ilyag ( 572316 )
        If I had the Windows "Clouds" wallpaper all over my room, I'd feel like ...

        You wouldn't be able to make out what that is. The wallpaper is 640*480, 16 colors. Imagine this scaled to the size of your room, if it starts looking bad on a big monitor already...

        ;)

        • Re:LCD/oLEDs (Score:2, Funny)

          by dootbran ( 467662 )
          The wallpaper is 640*480, 16 colors.

          Now this is actually benefitial to me, since my walls are the same ones that came with the appartment and the can't support anything higher than that... something about the reflectivity or texture not too sure I kinda zoned out when the tech guy started using those "big words". I'll probably upgrade one of these days.
    • Yes, but wouldn't it be the utmost embarassment to BSOD your entire wall at your next LAN party?

    • The seams would irritate me.
    • A few days ago I figured out a plan to make a projection TV that is 4 inches deep using interesting optics and compact LCD on Chip display. Sadly, I cannot tell you the inner workings because I am thinking of patenting it.
  • Now everyone can have a fairly affordable 50+ inch flatscreen display, for a truely awesome gaming experience!!!

    well if its dark in the room and you have enough windowless wall space anyway and enough room to put the projector and .. and.... Well on second thought, back to the drawing board

    • Re:Woohoo! (Score:1)

      by Anonymous Coward
      And as long as you don't mind 320x200 resolution on your 50" flatscreen you'll be ready to rock and roll!!!

      ymmmm 4mm pixels!! It'll be really good for playing those Atari 2600 games in Mame.
  • Combine these projection systems with white LED's [slashdot.org] and we might have somthing here! =)
    • If you take your average LED, and compare it to the output of a 500W spotlight, no comparison. The LED is thousands of times weaker(lightwise), so you would need thousands of them to light up a point, not to mention collumnating them(hit the same spots for the whole area).
      The only advantage you would get is heat dissipated, because 1000's of the buggers would chew, oh say, hundreds of watts anyway.
      Someone made a projector from lasers and mirror systems, but they are again, hundreds of times brighter, and can be directly modulated, but the 'pictures' are 'liney', scanlines showing everywhere. Unless you have a screen that amplifies the light, the LED idea just doesn't work. :(
      http://www.nofs.navy.mil/about_NOFS/staff/cbl/ LC_H andbook_v11.html
      Navy specs on light sources, look halfway down
    • Hum. the number of LED would make it more expensive than a regular projector.

      If you want cool light put the lights in a seperat compartment cooled by its own fan. IE pipe the light in. The box with the LCD must be either silver or pure white inside to not turn light into heat. Any dark spot will generate heat.

      I love these "why not concepts!" Keeps the mind active and thinking.

      A very long time ago though of mounting a monitor over a photocopier to make a printer.

  • Already slashdotted. (Score:3, Funny)

    by Quixote ( 154172 ) on Sunday May 12, 2002 @08:33PM (#3507869) Homepage Journal
    I guess they should also build a server to go with that LCD projector, just for such an occasion.

  • /.ed Already (Score:1, Redundant)

    by Mrdzone ( 562353 )
    It seems as though it is down already so here is the google cache [216.239.35.100]

  • Mmm (Score:1, Insightful)

    by Anonymous Coward
    No picture of image result....that suck.

    Is this another 50 feet Giant TV like project.
    Without seeing the end result I won't spend money trying it.

  • Reasons for Skepticism (Score:3, Insightful)

    by Schlemphfer ( 556732 ) on Sunday May 12, 2002 @08:36PM (#3507880) Homepage

    Interesting. Now is this confined to hobbyists because the LCD companies are too slow-moving to have thought of it first? Or is the whole idea fundamentally flawed?

    What I'd really want to see in the article is: Joe Blow built his own LCD projector for $350, and the image quality is better than what a good projection-screen television delivers.

    Instead, there are lots of plans from hobbyists making their own, but no clear word about whether even the best of these designs produces an acceptable image.

    One key thing: most of these designs call for a miniature 800x600 LCD monitor. Once projected onto a wall, how does that compare to the dots per inch of a regular projection TV? I bet it doesn't compare favorably at all.

    The big question I came away with after reading this is: why aren't the big LCD companies developing this kind of product? Maybe it's an idea that, even with big-budget R&D, won't produce an acceptably good image.

    • Re:Reasons for Skepticism (Score:5, Informative)

      by Anonymous Coward on Sunday May 12, 2002 @09:05PM (#3507959)
      In fact, the image quality on these systems can be much better than your typical projection television. I have a system such as follows:
      • Book sided pc with a Celeron 566/128mb, integrated sound (mostly left over parts+$75 for the case)
      • Generic BT848 tv tuner ($50 CompUsa)
      • Dukane 4000 lumen projector (ebay $100)
      • Active matrix Nview projector panel capable of 1024x786 native resolution ($200)
      Total $425

      I also got a 72" wide screen for $75 retail, but a flat white wall will do almost as well.

      The quality on the system with DScaler is very impressive at 1024x768. The only difference in parts between what I have an the author of the linked site is that I've not tried putting it all in a box. Currently it all sites on an end table next to my couch and projects onto a screen which hangs down from rafters. I see no reason why putting in a box would make a difference in the quality. It would probably make it better by blocking out extraneous light that escapes from the overhead projector.

      Now while the quality is excellent (you have to play with the brightness/contrast to get a good picture), there are quite a few drawbacks that don't have to do with image quality:

      • It get's damn hot. A 4000 lumen overhead projector bulb will heat up a small room pretty quickly. Fortunately I have very high ceilings (the screen hangs off rafters) so it's not too much of a problem
      • The fan in the overhead can be pretty loud, but I only use the projector for DVDs, and the volume of the movie is usually set pretty high.
      • The bulbs only last 75-100 hours. They only cost about $7 each (less in bulk), and my projector has a backup bulb replacement switch so it's rarely an inconvenience. The current halogen bulbs for stand alone projectors typically last 2000+ hours.
      • It's pretty ugly. After all it is an overhead projector on an end table, so it looks very out of place in a living room.

      My setup could use a little more CPU power. A better graphic card would be good too 'cause I had to settle on a Geforce 2 MX 200 because it was the best half height video card I could find. Also a sound card with a dolby decoder would make it even better.

      It does work, 'though, and looks great, but as you can see it's not perfect.

      -dameron

    • Thats like those dilbert books "wally if this idea is soo good how come other companies aren't doing it?"

    • I do share this concern; namely that the quality will be fairly poor -- but sometimes it's nice to have a very large image, even if the quality is sub par. For me, the question is if the quality is bad, or really really bad.
    • "Or is the whole idea fundamentally flawed?" - well the flaw is that it ends up being expensive to run because of bulb replacement.

      "why aren't the big LCD companies developing this kind of product?" - prehaps they feel the market's too small to warrant the investment in researching a new product.
    • Here'e the lowdown on the diffrence in a home projector and a better commercial projector, just to show the comparison as really apples and oranges and not apples and apples.
      Single LCD projector will never be as efficent as a 3 LCD projector because....
      Red light must pass thru a red pixel in a single color LCD. This means all the white light that hits green and blue pixels is NOT adding to the brightness of the red. This absorbtion of the 2 colors not passed by a pixel filter means 2/3 of the light is lost in the filter and turned into heat at the LCD where it is not needed. This alone limits bulb size and projected lumens. In a 3 LCD projector, the light is split into primary colors with beamsplitting dichoric mirrors. Therefore all the red of the white light does hit the red LCD (actualy a B&W LCD without a color filter). The LCD then only changes the polorization of the light. The polorizers take the heat, not the LCD. The polorizers are spaced away from the LCD allowing cooling the polorizers while not heating the LCD unlike a color filtered single panel LCD. The same holds true for green and blue. The 3 beams are then recombined into one beam and exits the lens to the screen. This overlaying of the colors gives true full color pixels, not a color stripe matrix display of adjacent red green blue pixels. The heat not removed by the cold mirror at the lamp is now spread out over 6 polorizers, (one each in front and behind each LCD) not in the one LCD panel. This allows a brighter light source to be used.

      Now the simple math..
      Light not absorbed by pixle filters, but routed to proper LCD = 3 X brighness. Point source arc lamp with cold mirror = 4 X more visable light per watt. 6 polorizers instead of one pannel to lose the heat = 6 X brighter bulb can be used. Polorizers seprate from LCD keeping heat away = 4 X more watts in heat can be safely absorbed without overheating the LCD's. 1/2 light absorbed by polorizers 1/2 (OK it does lose light)

      The totals
      Dichoric splitters 3X
      6 polorizers 6X, 4X, 1/2X
      Arc lamp 4X more usable light
      Total 144 times brighter projected lumens.
      Any incandecent light source single LCD projector will not come anywhere close to the 3 LCD arc lamp commercial projector in projected lumens for these reasons. A commercial one can be used on a trade show floor, where a home built will never overcome the ambient light.
  • A lot of dotcoms did digital projections for their clients... and if we use my company as a comparison, they could have saved $12,700 if they could have had two projectors for $300.

    Now, they only had two projectors... imagine how many some of the bigger dotcoms must have had, and how much money could have been saved had this been out earlier! ;)
  • "And it looks pretty simple, too"

    By simple are we talking about some of our fellow slashdotters hook the rest of us up, or are we talking simple for millionaire phds.
    • Millionaire phds? Where? None around me, anyway, and when I finish my Ph.D., I expect I won't be a millionaire either. I'm definitely in the (eventual-)Ph.D. that has no money so he builds projectors for $300 catagory. =-)

      -Paul Komarek

  • Almost did the same thing (Score:3, Interesting)

    by Anonymous Coward on Sunday May 12, 2002 @08:48PM (#3507916)
    I bought a panel projector from a junk dealer for 10$. This is an older model, 3M 6150, so it's TFT 640x480 18 bit color.
    Then I bought a smashed laptop screen for 5$ to get the backlight out.
    Put the two together and I got a 15$ LCD monitor, this is fine for messing around with older gear like the Commodore 64, or a PC in 800x600, which the LCD panel can scale.
    I'm pretty happy.

    CAUTION: Raw LCD panels are very sensitive to static discharge! Use a wrist strap.

  • How Dissapointing... (Score:4, Funny)

    by flewp ( 458359 ) on Sunday May 12, 2002 @08:48PM (#3507918)
    Here I thought the headline was "Homebrewed LSD Projections"... having to do with homemade LSD visions.

  • Google cache (Score:4, Informative)

    by InsaneCreator ( 209742 ) on Sunday May 12, 2002 @08:50PM (#3507922)
    See this page cached@google [216.239.51.100] :)
    • A better version (no highliting) here [216.239.39.100].

      The page isn't slashdotted just yet though...

      Why did I say that - it's probably being destroyed now...
      • It's almost gone now - took 30 seconds before I got a reply - probably quicker for everyone to just got to the cached page instead.
  • Great, now how do I install one of these for each wall in my house, and get a customised version quake where I can go running from room to room before getting zapped by a bouncing eyeball...?
    • Great, now how do I install one of these for each wall in my house, and get a customised version quake where I can go running from room to room before getting zapped by a bouncing eyeball...?

      Weren't the big eyeballs in Doom II?
  • Just in case the main site gets /.'ed, It basicly involves a powerful bulb being sent through a LCD. He is using 2 fresnels to help get rid of some of the distortion, but I'll belive the quality when I see it.

    A link from the main site: DIY LCD Projector [rr.com]

    BTW...My office just picked up a NICE LCD thingy. It has 4 video inputs, 2 computer inputs (displayed PIP-style or side-by-side), and a 100mbps ethernet switch. We paid close to $10k. In my opinion, it was worth every penny. I'd rather spend $10k on something worth it than $500~~$1000 on something not worth it.
    • "I'd rather spend $10k on something worth it than $500~~$1000 on something not worth it."

      If I had a lazy $10k i'd agree

      But all my $10k's are going to be pretty busy for the forseeable future.

      as it is i might just have a lazy $500.

      that makes this more interesting to me than your companies new toy.
      • If you don't have $10k for something you need, then you don't have $500 for something you don't need.
        • I think you need to polish your logic and/or maths skills.

          aside from that needs are rarely absolute, and wants even more so.

          in my case, my friends and I often borrow projection units from our employers for the weekend and play 4 player playstation games on the PS2 blown up onto a wall.

          We like doing that.

          I don't like it enough to pay $10,000 for a unit of my own.

          I might well like it enough to chip in $150 each with my friends and spend a weekend arseing around trying to build one.

          I frequently spend money on things I don't need, be it the ps2 or my motorcycle.

          I have $500 for something I want.

          I don't have $10,000.

          OK?

  • diyaudio.com (Score:2, Informative)

    by Sell0ut ( 231418 )
    A nice thread on DIY projectors, a lot of them are done with LCDs.

    diyAudio [diyaudio.com]
  • The sites seem to mention the results (when they succeeded) were kinda pixelated. Others have pointed out that the bulbs they use tend to have a short life. With an image of the projected image it may be able to make a better judgement. How does it compare to the lower end projects that cost about 1700 or so?

    As a side note, I'm looking at setting up my home theater to proper levels, and if these projectors display a good image, they seem to be a much more viable solution. Any one have suggestions regarding this? It seems that getting a 1000 lumens projecjtor that can do up to 720p isn't too unreasonable compared to any CRT or projection based TV solution. Is 1000 lumens sufficient? I'm specifically looking at the Mitsubishi SL1U Projector. I'm aware that watching TV/movies with such a system will naturally require a low level of ambient light, but two things are very cool about this.

    1) Pretty much as big a screen as I want, provided distance in the room. Speaking of which, how far back is needed to get, say, a 60-70" image? Again, having seating so as not to get in the way of the projector is another issu...

    2) When I move, large TVs are so unmanagable. The projector, and possibly a screen (maybe just use a white wall, provided the wall is smooth and white enough) Projector is on the order of 6-10 pounds, and the screen would be also manageable..

    Who all has experience with this? My current rig is an old 24" console TV from the 80s with gaussed spots all over and annoyingly cropped image, so it wouldn't take much to impress me.

    • Re:Dunno.. (Score:3, Informative)

      by turbod ( 114654 )
      Sounds like these guys are not aftercooling the bulbs. Most projectors I am familiar with allow one to shut it off, and if it remains plugged in, will keep its fan on until whatever internal thermal parameters for prevention of heatsoaking are satisfied.

      Allowing the bulb to heat soak is just as bad as running it without cooling.

      David
    • You definitely want a screen (it will be pretty expensive, but worth it), projecting against a white wall vs a screen is an amazing difference, a screen as reflective properties that most paints don't (and for good reason). So if you are planning on doing this, definitely invest the extra bucks for a nice screen.
    • Using the table on this page: http://www.princeton.edu/~conorneu/hdtv/basic.htm [princeton.edu]
      This assumes a 65" diagonal screen.

      For 4:3:
      (3x)^2 + (4x)^2 = 4225
      9x^2 + 16x^2 = 4225
      25x^2 = 4225
      x^2 = 169
      x=13
      That makes the screen height 39"
      NTSC (interlaced) - back 156" (13 feet) to 273" (22 feet 9 inches)
      SD DTV (progressive) - 97.5" (8 feet 1.5 inches)

      For 16:9
      (9x)^2 + (16x)^2 = 4225
      81x^2 + 256x^2 = 4225
      337x^2 = 4225
      x^2 = 12.5370919881305637982195845697329
      x = 3.54077561956848146706813581221355
      That makes the screen height 31.9"
      For HDTV - 79.75" (6 feet 7.75 inches)
      • Ummm, what did you just answer?

        Ignoring the fact that you have no units and too many significant figures (now I know why the engineering curriculum rides us so hard on labeling and s.f.'s), it looks like you calculated the height of a screen with a 65" diagonal but after that I'm lost. Is there something in there I'm missing, or are you flexing your basic algebra muscles?

  • other than hack value.... why? (Score:4, Informative)

    by Lumpy ( 12016 ) on Sunday May 12, 2002 @09:39PM (#3508041) Homepage
    You can get 800X600 lcd projectors on ebay for less than $500.00
    and these dont need a computer, just plug in composite video.. (I can hear it now the videophiles that have their 2048p projectors that use fiberoptic digital video and HDTV ready HD-DVD players will whine that it's grainey,low light because it's lower than 95,000 lumens and doesnt have glass lenses made by Plossol in germany... Go to hell videophiles..)

    The dayton hamfest is coming up very soon, you can get a (GASP) old technology video-tube projection tv for probably less than $300.00 that works fine. (granted, it's a coffee table, but hey...)

    the golden rule is that you scroung for a used one first, then look for cheap new, and THEN create it by hand.
    • and, how much are the bulbs for those $500 ebay projectors?
      • Pretty expensive, assuming you aren't handy enough to hack a lower-priced model into it (which isn't really all that difficult if you're at all handy... it's just a light bulb, albeit a very bright one).

        The original ones last for thousands of hours.

      • You can get 800X600 lcd projectors on ebay for less than $500.00

      OK, but when the next one comes up, then you can get it, or I can get it, but we can't both get it.

      I always have a bit of a chuckle at these "Build X for only $Y!", when Y is based on some completely arbitrary cost for a strictly limited supply of used hardware. And of course, every person who reads this (the original article or your suggestion) and thinks "I'll do that!" will hit eBay and drive the price up.

      Sorry guys, but if you're not quoting a retail source, you're just blueskying. We can't all buy/build for bargain prices.

      • that's not bargan pricing, that's real world pricing, ebay items usually go for greater than retail because of stupidity of the bidders (example - ham radio equipment)

        I can get them all day long for from $300-600 depending on quality.. Business auctions happen almost every day.. try checkin out purchase options that require the NON-use of a computer and the horrible task of going outdoors.

        (Last business auction I went to.. wire welder that retail costs $3500.00 I got for $125.00... computer equuipment usually goes for 3-5 cents on the dollar.)

  • DIY discussion (Score:3, Informative)

    by Anonymous Coward on Sunday May 12, 2002 @09:39PM (#3508043)
    diyaudio [diyaudio.com] has a 100+ page discussion of this. Most people are using an overhead projector with their standard lightsources, or mercury vapor or metal halide bulbs. The OHP's fresnel lenses get around the problem of having an LCD panel and lens with different sizes and not wasting a lot of the light(but they're kinda big). Pretty good results have been obtained. However, there are some caveats, the contrast ratio of lcd panels from desktop monitors are pretty poor(under 300:1), decent commercial projectors have contrast ratios > 1000:1. Although I haven't built one yet, I think this can lead to washed out images. Also, nobody has found a supplier for the nice 1-2 inch LCD's used in commercial projectors

  • Does it work really? (Score:5, Interesting)

    by pinkpineapple ( 173261 ) on Sunday May 12, 2002 @09:43PM (#3508050) Homepage
    My main interest is playing movies on the wall of my living room.

    This project looks nice if I can find someone to do it for me that is.

    I have a few concerns though.
    1) Aren't dvd players using Macrovision to forbid a signal to be output on anything else than a TV? The signal going to a video capture card seems to be a slight problem. Is this a reason why every one in the article is talking about LD and VCD, these two older media not suffering of the Macrovision "virus", er copy protection.
    2) Is this really cheap? I mean a dedicated P800 in the living room (cpu speed to cope with descaler complex algorithm)+capture card+LCD panel, etc... I don't even mention the electric bill.
    3) Noise level: Getting a Pentium noisy as an air carrier next to a TV and adding the noise of the fan(s) for cooling down the bulb(s), does that meant that I will need to listen to the movie with a pair a noise cancelling headphones?
    4) Space: I imagine that the distance from the projector to the screen needs to be consequent. I can't find data regarding the minimum size of a room to use the projector.

    I still like the idea though.

    PPA, the girl next door.

    • Re:Does it work really? (Score:3, Insightful)

      by Junta ( 36770 )
      Dunno about the rest, but DVD shouldn't have a problem unless these things have some sort of gain adjustment circuit built in. I know of no display tech that does this, only record technologies do this. MacroVision works essentially by inserting spikes into the video signal that trigger the auto-gain controls on VCRs to lower record levels to compensate, but the spikes are such that they are not too noticeable to people. In theory, they claim invisible to the viewer, but in reality it does come through a bit, so I disable when I can.
    • Macrovision works by fucking with autotracking. It sends signal spikes which throw the VCR off. A TV outputs the signal straight so while the quality is decreased, most people don't notice. I don't know if a video capture device would be affected by Macrovision, but I would guess no. There are Macrovision defeating devices which cost $50 at Circuit City though, so it is really just added cost and not a setback.
      • >I don't know if a video capture device would be affected by Macrovision

        It is if it's been built in the past while. The only video capture board I own unaffected by macrovision (and completely unable to be affected -- thanks ATI for cheaping out and buying the shitty chip!) is an old ATI-ISA TV card with the Bt819 chip. It can't record the VBI signals (where the macrovision colour burst is stored) so they can't be checked.

        Macrovision does nothing to a video capture card, however modern cards and software record the VBI signal and will check to see if Macrovision is present. If it is, you can watch it on a monitor, but you can't record it or output it to a TV (unless your output supports Macrovision generation, like most do nowadays in support of the MPAA).

        The solution today? Find an old card that either can't support checking for Macrovision / find an old card that has hacked drivers (Matrox Rainbow Runner!) / run an OS that doesn't care (Linux) / or, as mentioned, buy the $50 Macrovision stripper (this might not work for DVD players, though, since they support a stronger version of Macrovision output. If the $50 "video stabilizer" won't do the trick, buy a $200 Time Base Corrector -- this removes ALL forms of Macrovision, isn't patented or in any way illegal, and, as a side benefit are reported to improve video capture synch a LOT).

        :-)
    • You can strip Macrovision either with a hardware box that does this (about $30), or if you have a PC DVD player, with software (which also supports playing out-of-region DVDs, etc.)

      I had to do this for my own setup, which originally had an old TV that couldn't handle two inputs, so I had to feed the DVD through the VCR. Macrovision screwed up the color badly when I did that. I used a software solution ("Universal Selector"), and it works great.

      I use a PII-450 in my living room, and performance is fine. It has minimal fans and isn't too noisy. I have a Hollywood DVD MPEG hardware decoder, so that helps, since the video for movies comes out of that card, not from the PC. I bought a commercial LCD projector though.

      The space (distance from screen) simply determines how big your projected image is. You have to take the entire room size into account, where the seating is, etc. Depending on what we're doing, we sometimes put the projector in between us and the wall/screen, and sometimes behind the sofa. Behind gives a much bigger picture, but it's fainter in bright light, so for everyday use (as opposed to movies where you dim the lights and crank up the Dolby 5.1 surround sound), we have it closer. If you check the specs for commercial projectors, some of them give you these details.

      If you have a really small room, the size of your screen may not be worth the trouble. But if you can manage at least about 7 feet to 14 feet, you'll be looking at image sizes that are plenty big - easily up to 100" or more.

      I don't think you can really do this kind of stuff very cheaply and get good results. The point as I see it is more to get quality that rivals or exceeds that of your local cinema. You can get in that ballpark for a few thousand dollars these days, although you have to make some compromises at that level.

    • Macrovision Notes (Score:2, Informative)

      by CharlieO ( 572028 )
      MacroVision works by putting false sync and colour burst signals into the interlaced fields in a composite video signal.

      This fools AGC (Automatic Gain Control) circuits into thinking they have a very bright picture, and so they reduce the gain. By varying the signal you can make the picture brightness pulse, or in some cases cause it to loose track of the synchronisation all together.

      Conventional display devices don't have to have such accurate control of the gain of the signal, so are not very heavily effected, although it is possible to see the effects on some devices. You could see the high amplitude bursts, but these occur in the 'off screen' section of the field that holds the sync signals, and stuff like teletext - if you have vertical hold then you might be able to see them.

      (For a great technical and non-technical explanation check Repair FAQ [repairfaq.org] for an easy explanation check How Stuf Works [howstuffworks.com])

      Now originally this was intended to specifically block VHS style recorders, but as things have developed there is another device now in common use that can be effected, that wasn't around in consumer products when MacroVision was invented - the frame store.

      These are handy digital devices that read the composite video signal in and store it in real time. The video can then be read out in any format you want. Why would you want to do this?

      1) Stabilise the signal
      2) Change video formats from 50/60 interlaced fields.

      Now the first one is done during video editing so that different sources can be synchronised and things like picture in picture and wipe effects between 2 video sources will actually work. They are also now common in good prosumer VCR's for this reason. Digital camcorders have them by default because of point 2...

      The second point is that it allows you to do standards conversion in real time - such as in a capture card where you digitise the signal to a different frame rate.

      And here is the point - digital projectors such as LCD and DLP tend to use progressive scan rather than interlaced signals, so they contain conversion technology including frame stores to do the de-interlacing (good notes at SourceForge [sourceforge.net])

      So any device that uses a frame store approach can be effected by MacroVision, it just depends on how good the AGC in the framestore is.

      How do you avoid this? Simple really don't use a video signal that can have MacroVision on it. If you have RGB (component) then this won't have protection, and is the superior connection anyway for a projector. The S-Video source is normally ok as it seperates the chrominance and luminancne (colour and brightness) signals - although I've heard of a new 'level 2' MacroVision that can disrupt this - sorry no tech details on that I'm still looking, but I think it has to do with messing about with the chrominance.

      Of course the fact you regenerate the signal from the framestore means a good one is able to strip the MacroVision out, but there are cheaper ways to do that, and no I'm not giving the links - spend 2 minutes on Google [google.com], and remember that MacroVision is specific to PAL/NTSC so don't go ordering abroad! A good legal reason to have such a device is to connect a non AV socket TV to a non RF output player via a normal VCR, or to connect a projector sensitive to MacroVision when you don't have RGB Component output. Of course in the US you will fall foul of the DMCA, but we already know what a mess that is!

  • Make it even cheaper (Score:2, Informative)

    by yjjeep95 ( 570674 )
    I don't know where the first component could be found, but I could probably make a working model for around $200...

    1: 6mmx7mm LCD screen (don't know if they can be made that small with decent resolution for a reasonable price)

    2: Beseler 67 Photo enlarger

    3: Bank of 4-8 halogen lights (or a single car headlight?)

    4: Maybe a lens to focus the bank of lights

    The correct wiring and such to make all of it work. The Beseler will already have the correct lens for focusing a screen of that size, and if you replace the standard enlarger lamp with something like a couple of car headlamps or something, you can probably squeeze out enough light (with a lot of life to the lamp too) to get a decent display in a dimly lit room...

    Approximate cost (given a good day on ebay): $200

  • interresting... (Score:3, Interesting)

    by tcc ( 140386 ) on Sunday May 12, 2002 @10:01PM (#3508091) Homepage Journal
    That's one thing that is cool about projectors, they don't devaluate very rapidly (check on ebay for anything 1-2 yrs old) compared to high-end TV. Plus it's not a pain in the ass to move around, plus you can have the size of screen that you want when you have 800+ lumens and good screen. (well obviously the more lumens the better if you're to do 15' diagonal :) )

    When I see people buying HDTV TVs at C$5000+ I don't understand why they aren't looking a medium range projector with HDTV support. Okay you don't buy anything under XGA resolution because with all the resampling it'll screw up the quality big time, but still, at 5K you have a nice tv, but at 5K you have a BIG refurb projector that can do both progressive playback of your dvd, give you an image that has easily 4 time the area covered, and best of all, you can play quake at wall size!.

    In my case I've been trying to grab a cheap DLP XGA projector for a while, I don't want a 60 inch tv that will be a pain to move around, I want a 90 inch "tv" that I'll be able to plug my computer on it and also have fun watching movies like in the theatre :).

    The replacement lamps are very expensive, but then again, when you look at the "kit" they sell you for 400$, it's basically a specific lamp with specific properties (metal halide, etc etc) at a specific voltage, plus a little crappy plastic holder... there's no optics (you read "lamp module" you'd think it has some collimating lenses or something) and you can buy these same lamps from a third party at 1/5th of the price, and you just have to mount it back on the plastic thing that was attaching the old lamp. If you have to break it, so what, nothing a high-temperature epoxy can't fix.

    Anyways, nice to see articles like that, but LCD sucks, DLP is the way to go for video projectors, too bad parts are still expensive, anyone here knows a 3rd party supplier that won't only sell developper kits at 3K$?
    • Anyways, nice to see articles like that, but LCD sucks, DLP is the way to go for video projectors

      I've also been looking into buying one, and everything seems to agree that LCD had the edge over DLP - DLP is smaller, lighter, cheaper, but (a good) LCD apparently has the edge in image quality.
      The best projectors seem to be LCD, though there are pro's and cons to each. (Eg, LCD has space between pixels, while DLP colours seperate when your eye cicades from one one area of the picture to another because they use a spinning colour wheel instead of 3 seperate chips) and so on.

      Since DLP projectors seem significantly cheaper than LCD, it'd be great if they were better - so please tell me what you've heard.

      I'm thinking that even if LCD is better for some things, what I want a projector for is (1) Quake & (2) DVDs, so if DLP is as good or better than LCD for just those things, that would rock.
      (I can only afford one of these - so I have to get the choice right BEFORE I buy)
      • A big disadvantage fo DLP is that because it is light inefficient, it needs brighter bulbs with shorter rated run hours to achieve the same brightness.

        With LCDs, there is a prism that splits the light to extract the red, green and blue. The color wheel concept with "one chip" DLPs only allow one of those colors in the spectrum through.

        DLP projectors typically run from 1000-1500 hours on a very pricy bulb. An LCD projector often runs 2000-3000, and in some cases, as high as 5000 hours in economy mode, and the bulbs don't cost any more.

        DLPs are just now getting an edge in what is called contrast ratio, the ratio of the blackest black to the brightest white. LCDs currently max out to 700:1 at best, single chip DLPs can go much higher, I think there are some stock units that are rated at 1000:1, 1200:1, with modifications, some are getting 1800:1, this is due to the simplified optical path where there aren't as many optical elements to scatter light. Three chip DLPs have those elements and can't go as high in contrast ratio.

        The biggest problem is that the color wheel concept causes "rainbowing" and because it is composed of very high speed color flashes of red, green and blue, it cause headaches and fatigue in some people. It can take weeks to acclimate to them, but most people don't get enough exposure to acclimate, so it may not be worth the effort if you plan to have a lot of guests.
      • Sounds like LCD incumbent FUD to me.
        I've seen LCD and DLP side-by-side in a local mall and the DLP seemed to kick ass in a fairly bright environment. Now obviously there are hundreds of variables that aren't accounted for in my casual observation, but I'm surprised to hear someone who has seen DLP (wait, have you seen it?) suggest it's inferior to LCD. Everything I've seen and heard is quite the opposite --ie, DLP kicks ass over LCD in every regard and is likely to dominate the projector market within in the next few years. But I've been reading a lot of MEMs stuff and demos are easily rigged, so perhaps it's just hype. Nonetheless, I did see one that looked nice and sharp as wide as a theater screen in an environment that made LCDs look like crap.
        I've also seen some very expensive DLP boxes on the web, so I don't think you can safely assume that DLP is only a bargain solution. Besides, if you're assuming that it's not as good because it's cheaper, you might consider the manufacturing technique of the DLP being a significant advantage over LCD. So far, my understanding is that TI is still asking a bit much in licensing for the cheapskate interests in Taiwan --bless their stingy little hearts-- to jump into it, but when the price looks right for both parties, I'm assuming these DLPs are going to crash the LCD party in a big way which is just as well because that party has been charging too much at the door all along and there's no sign of prices dropping precipitously with such shoddy, labor intensive manufacturing processes. How can such a process compete against a chip based solution except through FUD?
  • How about setting up this configuration, not with an LCD screen, but an old CRT monitor? Would the output be too dim? Could you crank the brightness, or would you then loose contrast?

    i have dozens of old CRT's around for hacking.
    could i just put a fresnel lense on one and aim it at a lense, then at a wall?

    • Yeah... if you buy a full-page magnifier and hold it a certain distance from the screen, it projects. Unfortunately, the picture is VERY dim (my friends and I tried this). You'd want to build an enclosure going from the frenel to the monitor so that the other light doesn't light up the room too much. Its very cheap to do, but the results are not great.

    • Re:Here's an idea: (Score:3, Interesting)

      by -Harlequin- ( 169395 )
      How about setting up this configuration, not with an LCD screen, but an old CRT monitor? Would the output be too dim? Could you crank the brightness, or would you then loose contrast?

      A guy I know has done this. Yes, it works. Yes, it's too dim to make very much bigger than the CRT.

      He used it to project the visual swirly displays things of mp3 players onto the ceiling (dark room) at a party. That's probably the best use for it. Cheap and easy though - all you need is a fresnal lense :-)
  • These projects and the directions look great, but there is something missing... None of these people have posted pictures of or described the quality of the output. As in, if you built one of these projectors, would you regret having laid out the $400, or would you be psyched and loving the high quality video image on your wall? I mean, I would be willing to make the investment for my own apartment, and would even bring one of these into my classroom (I am a teacher) to use with my classroom computer. But will the result be worth it?

    Derek
  • I was going to ask why the article has all that equipment, but I guess it might be required if you're doing hi-res computer stuff on the screen (but then what's the point of hi-res? Why not just scale it down?). But if you just want to watch TV, all you would need is the overhead, panel (provided it has s-vid or RCA in) and a VCR or DVD player. Most of them nowadays have s-vid or RCA out (and s-vid to RCA is just a dumb converter away).
  • This is giving me some rather good ideas..

    I've been wanting to get an LCD projector for my living room, after playing with one from a club a year or so ago (the unit was already 3 years old). In average lighting in a friends house, we projected a TV image that was beautiful, from about 10 feet away, which made an image approx 5 feet tall.

    I don't want to spend the $3k+ to buy one from the store, but I'm more than willing to spend less than $100 on a small handheld LCD TV and junk store movie/slide projector.

    I'll post to Slashdot if it works. "Hacker Makes LCD TV/VGA projector for $100", with results. :) Now if someone would only approve that.. :)
  • I have a better recipe for a homebrewed LCD projector:
    1. Buy a typical overhead slide projector (the one your college has hundreds of)
    2. Get a flat panel LCD @ 14-15"
    3. remove the backlight from your flat panel
    4. slap the panel stripped of the backlight on top of your overhead projector
    5. Heh. There is no step 5!
    Am I missing something or is this a better approach to the problem?
    • SGI actually produced a product in the 90's which did exactly this. This was when they had high resolution monitors (1600x1200??) that people wanted to project. The difficultly was
      a) mechanically somewhat fragile - if it slipped/shoved off the projector, it cost
      b) the LCD diminished lumination a fair bit which reduced screen contrast in ambient conditions
      c) did I mention cost and fragility of backlight?

      A good idea which could and should have been improved.

      LL
      • Interesting. I still think my/SGI approach having more positive points than negative. Yes you will have to be more careful with it compared to a traditional projector but then you're saving at least ~$3000USD so some tradeoff has to be incurred. The diminshed lumination bit is something that bugs me but new overhead projectors have 2800 lumens illumination and more. I would have thought that should be enough to show crisp picture even through an LCD. Having said that I haven't tried building it yet so I simply don't know.

        What you gain with my idea is high resolution. For ~800USD you should be able to get a good overhead projector and a quality 15" LCD that will give you 1024x768. Even many high end LCD projectors can only do 800x600 which makes them completely unusable as a replacement for a monitor.

  • Okay, a little better than the Big Screen with a CRT and Frenzel, but if you want good TV this is not it. If you want a good cheap LCD just go on ebay and buy a used 800x600.

    Neat DIY, but really, it pushes forward all the things that are wrong with consumer AV. Low contrast rations, no idea about proper screen materials, poor color, bad scaling...you could go on and on about it.

  • Scam warning on building the LCD monitor described (Score:5, Informative)

    by eyefish ( 324893 ) on Sunday May 12, 2002 @11:24PM (#3508308)
    Please note that the monitor suggested for the experiment (at this link [mp3playerstore.com]), claims to have a resolution of "960(H) X RGB x 240 (V)=230400" which can be a bit misleading if you're not too tech-savy on these numbers.

    Note that the horizontal resolution is NOT 960 pixels, but rather 320, since they're counting each RGB pixel as THREE pixels (very sneaky indeed).

    So just be warned in case you thought this was the deal of the century.
  • WOOOOOHOOOO! Finaly! Now a cheap bastard like me can afford me some BIG SCREEN pr0n! Pass the quart of immitation butter flavoring please... /=^)

    Dr MPF
  • If you can get decent quality 1-2" LCD screens, why not just rig them up on a pair of glasses, run the hardware off either a cable or a short range video transmitter and watch a seemingly immense screen with no noise, no bulbs...granted this is only good for one person... Shrug

  • Encounter w/ Law Enforcement (Score:3, Funny)

    by coolgeek ( 140561 ) on Monday May 13, 2002 @01:14AM (#3508643) Homepage
    COP: Tell me son, why exactly were you purchasing a metal halide lamp?
    GEEK: Well sir, I am a hobbyist, see
    COP: interrupts A hobbyist, huh?
    GEEK: yes, I am making a homegrown
    COP: interrupts homegrown, huh? Son, you have the right to remain silent...
    GEEK: LCD PROJECTOR! SIR!!! A HOMEGROWN LCD PROJECTOR!!! YOU KNOW, one of those things that projects computer images on the wall.
    COP: Images on the walls. Hmmm...you must be pretty good at your "hobby"

  • No. (Score:3, Informative)

    by brooks_talley ( 86840 ) <brooks@noSpam.frnk.com> on Monday May 13, 2002 @02:56AM (#3508846) Journal
    Sure, you can use a fairly normal lamp and a fairly normal LCD panel to produce large images on a wall. Heck, you can do it even cheaper with a bunch of colored markers, some saran wrap, and a light bulb.

    If you absolutely do not care about video quality, it's easy to get/build a projector on the cheap.

    However, today's typical $3500 projector includes:

    - A truly full-spectrum lamp. Retail price: $425. Wholesale price: $300. Manufacturing price: $250.

    - Built-in line doubler. Most LCDs have 768 vertical pixels; some have 600, some have 1024. DVD's have 525 vertical lines. VHS has something like 240 lines. How do you get from 525 or 240 to 768 or 1024? Anyone who knows anything about computer grahpics will realize that the answer is not "double every 1/X line". Line doublers interpolate lines on the fly.

    - Progressive scan support. Again, not a huge big deal, but the way I read the article, not supported.

    - Component video in support. Like progressive scan, increasingly critical for decent video.

    - Distortion correction, especially trapezoid. It's very rare to be able to project from the geometric center of the screen. Most of us have to live with projecting from the ceiling or floor, and use optical or digital means to correct the image for that.

    Sure, you can build a "projector" for $400. Heck, you can probably build one for $100 (see earlier lightbulb, saran wrap, and markers note). But if it were really that easy to produce a home theater quality projector for $1000, don't you think any of the mass producers would have done it? For less than the cost of a one-off? (Anyone who responds that all 8 major projector manufacturers are colluding in price fixing should be laughed at).

    Cheers
    -b

  • Improvements I'd suggest (Score:3, Interesting)

    by Yarn ( 75 ) on Monday May 13, 2002 @04:27AM (#3509020) Homepage
    Use a polarising mirror and a wave plate, so that polarised light is passing through the LCD.

    The reason for this is that with unpolarised light *half* of that light is just being absorbed by the LCD, and lost. This of course gets turned to heat and reduces the lifetime of your display.

  • Just buy a used projector (Score:2, Insightful)

    by Bart ( 12323 )
    I bought a used projector on ebay - no hack value but plenty of instant gratification.
    Here's another one...
    Like New Epson Projector, Remote, Low Reserve [ebay.com]

  • Many things missing... (Score:3, Informative)

    by Anonymous Coward on Monday May 13, 2002 @06:28AM (#3509173)
    I'll try to list them.

    You need a metal halide light bulb and ballast. Metal halide light bulbs are many many times more efficient at turning electricity into light, and thus produce far less heat. They also provide a 'whiter' light than a standard bulb. These are about $200 from hydroponics shops, and range in power from about 200-1000watts.

    You need a 'cold filter' to block out the UV rays the light produces. Without this, the ultraviolet rays will actually start killing pixels. This happened to my projector. These little peices of glass alone cost around $200. But without one, you will cook an LCD very quickly, especially with higher powered lights.

    By the time you get a decent lense, so you can actually get a decently sized and focussed image, you are starting to get into the sort of money that a decent 2nd hand projector goes for, without all the pitfalls.
  • A lot of people have commented on how these thing actually look, whether they actually work, and why anyone would want to do this when they could buy one used or new...

    1. What do they look like? Depends mainly on the LCD and lens system, not to mention the "case" of the projector. If built right, with good components and a "light tight" case, it can look good. Not great, not HDTV ready, but good enough to watch TV or a video with.

    2. Do they work? YES! Built right, they work as they should. LCD projection isn't anything really fancy - it is basically a slide projector with the LCD display substituted for the slide, and the backlight being a very bright lamp. You have to cool the LCD in some way (or polarise the light properly) to keep the LCD from "shutting down".

    3. Why do this? I would say it is mainly a hobby, but I would also say it is because most of us can't afford a decent new or used projector. New projectors are hella expensive, and used ones maintain their value, and are thus not that cheap either. The only ones cheap enough are the large CRT projectors, which tend to be real heavy, need to be aligned after moving them, and need special support structures to hang the heavy weight from the ceiling (if that is how you want to mount yours).

    I can't say I have ever built one of these projectors, but I can say how they probably look. I currently own a Fujix P401 portable LCD video projector. The thing is about the size of a couple of VHS tapes stacked upon one another, and it uses a small one inch LCD with a halogen lamp (it is a 6 volt halogen reflector lamp that is VERY difficult to find). It takes composite input, and has a system to either project on a small internal screen, or out to an external screen. Built in stereo speakers and the ability to run off of an 8mm video camera battery completes the system.

    The quality is OK. At larger image sizes the pixels start to become apparent, but all in all it really isn't that bad of a projector. If I keep the image to around 40-50" diagonal, it is highly watchable (you need to be in a darkened room), great for videos. I have used a VGA->TV convertor successfully with it, and viewed VCDs under KDE.

    I would expect a home-brew solution to be as good or better. I would imagine the larger LCDs to be higher resolution, and should give a sharper image at the larger sizes, with less "pixelization" (which really isn't a big deal on my P401).

    I honestly don't understand why LCD projector manufacturers don't (or won't) make cheaper, lower-res units. I would think a 640x480 unit would only cost $500-700 - a lot of people would eagerly snatch it up. It could be made compact and lightweight. Make it easy to attach to a computer video card or composite/SVHS inputs. I think it could sell. I have a similar gripe regarding laptops (ie, why not a 640x480 cheap laptop), but now is not the place.

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