PetaPixel

Build a Cheapo Photo Projector Using a Phone, Shoebox, and Magnifying Glass

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Want a cheap and simple way to project photographs from your smartphone onto your wall? Photojojo writes that you can actually make a makeshift projector with a few things you might already have lying around. Total cost: $1.

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The basic ingredients are a shoebox and a large magnifying glass. The shoebox will house everything, and the glass will serve as the projector’s lens.

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Basically, you’ll want to darken the inside of your shoebox, and then carefully mount your magnifying glass lens onto one end (making sure there are no light leaks).

Then, simply place your smartphone inside to have what’s on the screen be projected through the glass. You’ll want to figure out how to flip the screen upside-down (it’s different for each smartphone), since the magnifying glass will do a flipping of its own.

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Focusing the image on the wall involves moving the phone closer and farther away from the lens. For best viewing, you’ll want to make your screen as bright as possible and the environment as dark as possible.

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You can find a step-by-step guide on this idea over on Photojojo and in this Instructables tutorial by Matt Bothell.


Image credits: Photographs by Photojojo


 
 
  • hohohoh

    wow

  • cObvious

    There is no way in hell this works.

  • http://ddon.myopenid.com/ John

    Assuming the quality of the image is nothing to write home about, else this would be a great cheap movie projector…. :)

  • Bua

    April 1st is it?

  • Jake

    Tried it handheld with my DSLR screen. It works well and I was able to get the image about a foot wide and reasonably sharp (for a dollar store magnifying glass), but it’s pretty tough to line up the lens perfectly, with the right distance between the wall, the magnifying glass, and the camera, and the screen needs to be pretty bright. I will try again with a proper fancy shoebox setup. :P

  • http://www.facebook.com/Sideromelane Stewart Doyle

    I’ve done this myself, it’s not hard. Although I’m tempted to try it with a stripped down digital photo frame instead, the bigger screen should provide more light, and an external power source means the phone won’t just go into power saving mode after 90 seconds or whatever it happens to be set to.

  • derekdj

    You can do a quick experiment with just the magnifying glass and phone in a completely black room. It actually works with all magnifying glasses, but depends heavily on the magnification power of the glass. I tried with a cheapie 2x plexi lens and got a 8 inch image, I tried again with a 8x glass lens and got a pretty nice 5 foot image (the only room I could get completely black is pretty small).

  • Kodachrome64

    So if you take a slide, put a light bulb behind it, and put a lens in front of it, that will work fine. But if you take a phone screen, which is pretty much an illuminated image, and put a lens in front of it, all physical properties of the universe cease to exist and it doesn’t work. Interesting hypothesis. And your name is…..Captain Obvious, I presume?

  • AW

    Anyone know a way to do this that is much higher quality even though it costs more, e.g. up to $50 or so, but gets a big, clear sharp image? I’m interested.

  • Sam

    There’s no mystery about this. The “camera obscura” goes back at least hundreds of years and was this basic design. The earliest pinhole cameras worked like this. The first commercially available home projectors (made by a company called TheatreVision, in Maryland) were essentially just CRT televisions, with a plastic housing and a lens stuck to the front.

  • zim2411

    You can crack open an LCD, remove the backlight, shine a high power bulb through it, and use the lens to focus it. But good luck getting even marginal results with it. I did a build in high school with a friend, and we poured around $400 into it. While we did get a big image in the end, it was dim, hard to focus, loud, and the projector itself was huge. A $200 projector these days would have outperformed it.

    An easier way is to find an old overhead projector, and lay the LCD panel on it. But again, that’ll provide pretty poor results.

  • spookysr

    I would like to try a bigger black-box (maybe constructed of wood), a small-ish inverted LCD flat screen monitor with it’s stand removed, a flat paper-thin rectangular Fresnel Lens (senior citizen’s reader magnifier page), and a thrift store movie projector screen (retractable). In this model I don’t think you need to turn down the room lights too much. You will have to set the monitor’s brightness & contrast to the highest level. You don’t need a LCD monitor as you may be able to get more light from a CRT model but it takes far more room in the box. The focal length is around 12″ from the lens inside the box. The farther away from the screen the larger the image is. The darker the room the better. I just hope your mom or wife doesn’t go ape when she sees this monstrously in her kitchen or den!

    Most of this stuff is at your local thrift store (Good Will, Salvation Army, Savers, etc.). The wooden black box (and paint, screws, tools) is at Lowe’s or Home Depot. A stationary store like Staples or Office Depot will have the Fresnel Lens.

    Run the cable out to your PC or Laptop’s external VGA socket. You can run your display in extended mode or dual mode. That way you’ll have two screens running. The display and the projector.