I’m refering to this site. It claims to turn any TV into a projection TV (up to 100") with less than $20 worth of parts from Wall-mart and Radio Shack.
There’s obviously some serious chicanery going on here. I’m just wondering what the hell they’re talking about. If it “works” is it really crappy? Is it remotely feasable?
I’m not sure about this specific system, but it sounds an awful lot like something I saw with similar claims years ago. Basically it consists of a magnifying lens and a mirror. You put the TV in a darkened box with the screen facing up, and use the lens and mirror to project the image onto a wall or screen. Technically, it does project a picture, but you have to have virtually zero ambient light in order to see anything at all.
You have to use a wall or ceiling to stay under the $20 mark.
The mirror/lens contraption will not look good, the picture will not look good, you need a clear wall, and a clear area between the TV/mirror/lens contratption and the wall. If you put the TV/mirror/lens contraption in a box to make it look better, you’d need an IR repeater or some way to get the remote’s signal in there…
Instructions are available for free with a little Googling. The are sites which make the instructions available for free and just sell the parts.
Found some links here and here that show more details. (I googled on fresnel lens and “bed sheet”, as I recall those are the two key components here. 
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The previous posts are right. Your TV is not made for projection, so the picture will, IIRC, not be as bright as a proper projector. Also, you’re magnifying the TV screen, so you could end up with hugantic pixels (or whatever you call RGB sections in TVs, I forget).
That’s basically what I thought it was, but I was still curious. Thanks for the research and insight.
I don’t have the cite to the particular episode, but TechTV’s(Before it merged with G4 -G4TechTv.com) “The Screensavers” sent away for a kit similar to this, and it was lenses and mirrors and the like. They tried using the contraption on the show, but could not get it to work, in fact they stated that the screen size had decreased.
People sell these “kits” on eBay (search for “100 tv”). Here’s one.
Strangely the seller has lots of positive feedback, although some buyers are less than impressed:
It’s a slightly disingenuous argument, like the economist who refuses to pick a $100 bill off the ground because “in an efficient market, $100 bills won’t lay around on the ground,” but here goes:
If it were possible to build a 100 inch TV from $100 of stock parts and a COTS television, they would already be prepackaged with a slight markup on the shelves at Wal-Mart. If someone tells you that you can have something that costs $3,000 mass-produced retail for anything less than half-price, you should do some serious soul-searching and ponder the wisdom of P.T. Barnum. Then ponder the wisdom of “Weird” Al Yankovic:
Do you really want to see that?
This has been my experience. For the Superbowl one year, the people in my dorm room tried hooking up a TV to one of the college’s projectors (these things aren’t your basic overhead projector.) Anyway, the picture was washed out, the pixels(?) were very large, and since we were trying to project the picture on white vertical blinds it just got worse thanks to all the seams.
I gave up after the first quarter and watched the rest of the game in my room.
Modern VGA or XGA projectors are getting quite good and much cheaper than a plasma screen. For a bit over $1000 you can get a nice projector to watch TV and use your computer on. Keep in mind the bulbs cost $200-$500, and typically last 2k-3k hours.
You see that all the time on ebay. Obvious scams or over-hyped rubbish that nevertheless have glowing feedback. You can only conclude that either people leave the feedback before they’ve actually tried it, or the people who buy into these things are too stupid to realise when they’ve been taken for mugs.
Of course, there is the other possibility; it really does work. But I honestly can’t see how. The picture on a TV is simply not bright enough to successfully project over a much larger area.
I’m wondering what the $20 in Radio Shack or Walmart parts are. I didn’t think that Radio Shack or Walmart sold lenses (let alone one big enough for a TV), which seems to be the critical parts. I do remember buying projection television lenses from Edmund Scientific about ten years ago, so you can get the parts but from Radio Shack?
I saw these for sale before but they were hawking it as a PC monitor upgrade. I was fascinated for a while but as you have read the results are less than spectacular.