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Hardware Hacking

Searching for a Cheap Overhead Projector? 26

Posted by Cliff
from the instant-diy-"lcd-projector" dept.
stinkjones asks: "I recently found a project on Hackaday, which I found very interesting. It was linked to Tom's Hardware, and involved a massive, and cheap, projector. I have an LCD projector, but this seems like a great project with a pretty cool result. I already have an LCD that's perfect for the job but overhead projectors are hard to find. Retail they are around $500 new or a lot more, and if you can find them used they have a huge range of prices. Does anyone know where to find a cheap one?"
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Searching for a Cheap Overhead Projector?

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  • .. i mean, even in the 80's we were doing this ..

    but then i realized that with LED pocket projectors bound to end up in the aldi discount bin within a few months, its no longer such a fun DIY ..
  • by farty (701408)
    Go ask the technology department of a local school, they are usually willing to part with an older one for free or very inexpensively.
  • Less than $200 new (Score:4, Informative)

    by jayrtfm (148260) <jslash@nOSpaM.sophont.com> on Sunday May 15, 2005 @08:33AM (#12534922) Homepage Journal
    B&H [bhphotovideo.com] has the 3M 1720 for $130.
    Or you can JFFI [google.com],
  • University (Score:5, Informative)

    by adamjaskie (310474) on Sunday May 15, 2005 @08:59AM (#12535015) Homepage
    Most universities will get rid of old stuff the school doesn't need. Old computer equipment, everything from Pentium 133 PCs to beige G3s to old IBM mainframes, big plotters, copy machines, desks from renovated dorm rooms, and all manner of odd scientific equipment that nobody knows what it does. Sometimes a university will have a big warehouse that they sell this stuff continuously from, and sometimes it is just a big auction sometime during the school year.

    You could probably find an overhead projector there.
  • I helped a friend do this using a small tv instead. All you need is a lense, and switch a couple of wires in the tv to reverse the picture. Works fine, and small tv's are a whole lot cheaper. Shouldn't be hard to find the detailed plans, leave the expensive homemade lcd projectors for the rich guys.
  • by Solder Fumes (797270) on Sunday May 15, 2005 @09:27AM (#12535112)
    If you resign yourself to spending $150-$200 in addition to the LCD, you can get some amazing results. To be honest, any cheap overhead projector will have a halogen lamp that has too low of a color temperature, too dim of an output, and will need to be replaced every 25-50 hours. The cost adds up. Also, virtually no overhead projector is big enough to light the entire area of a 15" LCD. You will lose up to 60 pixels on both sides of the screen.

    If you instead build your own enclosure, you can do some neat stuff. First, you can show the full 1024x768. Also, you can use a metal halide bulb, which typically have a clean white color and put out less heat for the amount of light produced. And metal halide bulbs last anywhere from 8000 to 20,000 hours. You will also be able to get a high-quality lens for good focus across the whole display, something a cheap overhead might not be able to do.

    Go to http://www.diyaudio.com/ [diyaudio.com] and visit the Moving Image forum. There are thousands of posts containing ideas, plans, calculations, optics sources, and photos. I'm in the process of building my own projector with a 400W 6500K metal halide bulb, here's a photo of the image projected by a test mockup: http://lserve.homelinux.net:7780/diyaudio/lightsof f.jpg [homelinux.net]
  • by Spokehedz (599285) on Sunday May 15, 2005 @09:38AM (#12535171)
    www.itscrap.com

    No, that's not a typo. That's really the website. We have tons of stuff (50k square foot facility) that just goes to the scrap heap. Some things are sold pennies on the dollar, because there cheaper to ship then they are to scrap.

    We have, at this point in time, about 5 projectors in stock. And I bet even one of them works.
  • LumenLab (Score:3, Informative)

    by WonderSnatch (835677) on Sunday May 15, 2005 @10:10AM (#12535324)
    Lumen Lab [lumenlab.com] has some good plans and even better forums. I find it to be worth the $20 you have to pay up front. Before you pay, you can check out the projectors people have made in the Project Gallery [lumenlab.com] forum.

    The money is used by the fellow who runs the board. He builds projectors, trys different pieces and part out, and most immportantly, gets custom lenses made for their community.

    Hope this helps,
    Brett
  • I've seen old overheads in almost every thrift store I've visited lately. They're all over the place. I bet you'd find them at flea markets and almost every other used crap sale on earth.

    Did you even try to find one before posting?
  • Search for "Overhead Projectors" on ebay.

    I found 316 items - many of them actual projectors.

  • Call the colleges in your area. Odds are that their Media Services department, or whatever they're calling the AV Club these days, has a pile of them to get rid of.

    We've got a whole storage room full of the things at work. One gets trotted out for some antediluvian professor who still uses transparencies every once in a while, but most of the time they're just gathering dust. I doubt we're unique.

    --saint
  • Cheap overhead (Score:3, Interesting)

    by David_Bloom (578245) <slashdot@3lesson.org> on Sunday May 15, 2005 @12:14PM (#12536046) Homepage
    I got one at Iowa State University's ISU Surplus [iastate.edu] for $2. Sorry, they don't offer financing. I also got an LCD panel *designed* to go on the overhead for $30. One thing you should know: overhead bulbs often cost $20-$40, and rarely last more than 100 hours. This may make an LCD projector more practical in your case.
    • Good to see that some ISU traditions are still alive. I bought my first computer (a Sol-20) at their weekly warehouse sale back in '83, then spent a weekend wire-wrapping a 64K SRAM board for it. I remember paying more for the memory board components than I did for the computer. I used the computer for several years, becoming quite familiar with 8080/Z-80 assembler and CP/M.
  • Check your local newspaper for the next surplus auction of your local school district. At the last one I went to, someone bought 24 overhead projectors for $1 (mainly to get the auctioneer to move on to the good stuff).
  • by jptechnical (644454) on Sunday May 15, 2005 @05:38PM (#12538075) Homepage
    I saw those hack sites on making a projector with an lcd screen, it is nothing new.

    What I don't understand is why you have to Ask Slashdot this? The plans I saw had all these suggestions already mentioned. Check local and state surplus sales and auctions, checkout ebay, there are many places. A couple minutes of research would've pointed you in the right direction.

    If you need this kind of hand holding perhaps you should start with a more simple mod, like changing a tire, or setting the time and date on your VCR.

  • I got one word for you. ebay.
  • Years ago, most bowling alleys used overhead projectors to display scores to the crowd. These days the score-by-hand system has been replaced at most places, but you might be able to find either the old equipment in storage somewhere, or an alley that is finally getting around to switch to automated scoring (and ordinary CRT displays).
  • We got that LED projector comming out soon for around $700. 800x600 res but you wont have to worry about replacing bulbs. Small as hell lets see how good the lighting is cause it may be a winner or a weiner. Its due out like next month so leave your LCD alone or sell it to make the difference in price. Trust me you'll be alot happier with something that will definatly work (if the reviews give a thumbs up), and wont sound like a deisel engine while trying to watch a movie.

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