Archive through September 12, 2004
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New member Username: MotleyPost Number: 6 Registered: 12-2003 | And then, secondly, HOW is cardboard TV "worth it"? I ordered the plans myself, so I know what you get is total rubbish and not what these splashy websites claim (i.e., "IT RIVALS AN LCD PROJECTOR" and "IT'S JUST LIKE IMAX!"). If you scroll up, you'll see where we discuss the SPECIFICS why cardboard TV doesn't measure up to a more expensive home theater. If you want to go ahead and build the fresnel TV, fine. Go ahead and do so, but just know the limits of what you're getting. Fresnel lens TV is nowhere near the quality of an LCD projector, as these websites claim. The claims they make are FALSE and therefore a SCAM. In posts above, I and others discuss these points in great detail. On the other hand, if you still choose to build cardboard TV, who's business is that but yours? NOBODY CARES IF YOU BUILD IT AND LIKE IT. My only argument is, build it for free instead of lining a scammer's pocket. It seems pretty stupid to click on a fancy website when you can just click here or other sites on the internet and get the very same thing for nothing. Then, if you don't like the product, what have you spent besides time and printer paper and materials? However, if you scroll up, you'll notice when people like me present arguments like this, we get called names and dismissed as rabble rousers. The fresnel lens product is not "great" and anywhere near a substitute for an LCD projector, overhead platen system or rear projection TV. If anyone here thinks it is, where are the arguemnts making SPECIFIC points to back up their claims? If you scroll up, you'll see where I and others have made SPECIFIC arguments to the contrary. These bombastic "I like mine, so screw you" arguments just won't cut it. How about some posts about WHY this fresnel system is all that and a bag of chips? Those are curiously few and far between on this thread. That speaks volumes. |
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Gadgit Unregistered guest | I agree Dont line the scammers pocket if you want a fresnel lens you can get them on ebay now for $1.95USD or a stationary shop. I have built a projector at first I got sucked in to getting a fresnel lens but the results where very avrage and no matter how much you tweak the setup the image would not compare to even an entry leavel lcd projector. But then I got hold of a 150mm triplet lens and now I can say the image is very compareable to that of a lcd projector just a little darker at a guesstimit 550-600 lums but with the right high gain screen it is viewable in a lit room or in the day with the blinds drawn. |
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New member Username: Bigbear777Post Number: 4 Registered: 12-2003 | www.webtv100inch.com is where I purchased mine. This project worked great and they even had a section on how to make a silver screen which brightened my picture 3X. Highly recommended! Great DIY project! |
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New member Username: MotleyPost Number: 7 Registered: 12-2003 | Big Bear... you are a broken record. Yes, we know you got yours from webTV. Now, can you respond to my two most recent posts above? Thanx! |
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Gadgit Unregistered guest | But you can tell its dodgey when they say on there sites "GET OUR SECRET PLANS" when the plans are so simple and they ar'nt a secret at all infact they got them off another site that was giving them away free and the screen shots you can tell they are from a LCD projector because the edge of the scree would'nt be as focused as they show with a fresnel lens or as bright It's these ppl that burn the idea of DIY projection because ppl get there lens and get dissapointed when there image dosnt look anything like the screen shots they show Yes Big Bear it is a great project and I am still develiping mine but if you get a good optic glass lens with a dia of over 100mm and a focal lenght of 500mm you will see that the image you are getting now is inferra to what it could be |
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Steven Word Unregistered guest | It took me about an hour and a half to build my projector (without using any plans, just common knowledge of how projectors work.) And mine works great. I have it projected about 60" on the ceiling above my bed. I have added my own (different) parts to my projector to achieve controlled brightness, limited color bleeding, and light focusing. Here are a few pictures (taken today, January 3, 2004) of my projected image. http://rock.jazzerace.com/projection.jpg http://rock.jazzerace.com/projection2.jpg http://rock.jazzerace.com/projection3.jpg As you can see, they ARE definately watchable and worth the 6.00 total I paid on ebay for my lense. |
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Steven Word Unregistered guest | Also, in the first picture, I forgot to zoom out on the camera, hence the slightly heavier blue than the two last pictures. |
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Steven Word Unregistered guest | blur* |
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New member Username: MotleyPost Number: 8 Registered: 12-2003 | Steven Word...since you think this contraption "works great", let's see you answer the two posts above that I directed to Big Bear. And be specific and detailed in your answer. This "works great" and "I like mine" jazz is tiresome. |
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Steven Word Unregistered guest | I assume your first question was "Why would anybody order from a website when you can get the same thing for free right on this board?" Well, like I said, I didn't buy the plans. I used my knowledge of projectors to build mine, along with tweaking it by using the plans. And you're right, the fresnel lense/cardboard projector does not rival LCD projectors, but I didn't say that it did. I basically stated that the picture I got is worth it, and definately clear enough to watch. If you want the results of an LCD projector, BUILD AN LCD PROJECTOR. If you KNOW the results of a fresnel projector aren't as good as the LCD, then why even bother replying to the post by someone saying it is? Just let them think that. |
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Jack Sparrow Unregistered guest | I bought and made the projector box thing and found that if you turned the frensel one way the pic sucked but the entire screnn came in and the other way the pic was great but you have to have a true flat or lcd screen to display off of to get it to show more than just a circle in the middle. I'm looking forward to getting to try it with a flat screen. |
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Steven Word Unregistered guest | Here's a drawing of my projector. It's a bit different from any other plans because I added things to help direct light. http://rock.jazzerace.com/projectiontv.jpg |
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Unregistered guest | I builtThe projector using a basic magnyifying lense, about 2in wide. But it is only clear in the center the rest is really blurry anyone know how to fix that? |
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Unregistered guest | I built the projector using a basic magnyifying lense, about 2in wide. But it is only clear in the center the rest is really blurry anyone know how to fix that? |
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Gadgit Unregistered guest | The lens you have is probably a plano-convex, thesse lenses are directional so flip it around and see what the result is. |
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New member Username: MotleyPost Number: 9 Registered: 12-2003 | Steven Word: What do you mean why do I bother to reply to a post from someone who says fresnel lens TV is as good as an LCD projector? Because that's my right in a discussion, just like anyone else has the right to reply to me. If others used your logic, they shouldn't reply to me when I say that fresnel ISN'T as good as an LCD projector...they would just let me think that it isn't. However, they don't use your logic and neither do I. Secondly, I'm not carping about those who get plans for free. I have a beef against fancy websites - a few of which Big Bear posted - that make ridiculous false claims that cardboard and plastic can rival an LCD projector. I just hate scams. I just think these "I like mine" posts which curiously then list three or four links to these scam sites need to be questioned on this board. Others are like you and Gadgit appear to prefer discussing how to build a home made projector and that's up to you. I am targeting the listed topic of this board and calling out those who I suspect put up these scam web site to take advantage of the curious and gullible. In my view, that they are bold enough to post on the very message board that's supposed to (in my humble view) offer open and honest information about the issue is unconscionable and deserves to be exposed. They're already all over the internet and they're on THIS BOARD TOO? That's why I'm busting 'em. |
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New member Username: MotleyPost Number: 10 Registered: 12-2003 | The second question: "How is fresnel TV worth it" you answered also, but with the same curious reply that others have given. You admit that fresnel doesn't match up to an LCD and you make your peace with that. FINE! No argument there. If those are your standards, (like I keep saying) "have a coke and a smile". Nobody cares. All I'm saying is call the limits of fresnel TV like they are...don't imply that the cardboard contraption in any way or form is an adequate substitute for an LCD projector. However, if you click on any of these fancy websites, you'll see claims and "testimonials" to the contrary. So, don't question me because I'm pointing that out. Question those who make those claims and put up those sites. Then newbies who check into this board won't get sucked in. |
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Anonymous | I have this projection device that doesnt requir much building but it is in developemant will be out in two months you can log on and register ur email for updates plz, it is a revolutionary device. works with 13 to 22 inch tvs. just goto www.projectbig.net.tc |
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Anonymous | I have this projection device that doesnt requir much building but it is in developemant will be out in two months you can log on and register ur email for updates plz, it is a revolutionary device. works with 13 to 22 inch tvs. just goto www.projectbig.net.tc |
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Anonymous | I have this projection device that doesnt requir much building but it is in developemant will be out in two months you can log on and register ur email for updates plz, it is a revolutionary device. works with 13 to 22 inch tvs. just goto www.projectbig.net.tc |
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New member Username: MotleyPost Number: 11 Registered: 12-2003 | ??? And these scammers keep on posting here! This PROJECTBIG.NET claims "Imagine turning your normal sized tv, into a 100 inch VIDEO Entetainment system, by just spending less than 50 dollors." ha ha, guess who's most likely going to rake in the "less than 50 dollars? THEN COMES THE SCAM LINE (Big Bear and Steven Word, are you reading this?) The site claims: "This amazing device gives a good quality image as some of the 50 - 60inch flatscreen tv selling on the market for $1500 - $2000". So, let's review, class. With ProjectBig.net, we are supposed to get an image as good as a 1,000+ flatscreen tv for LESS THAN $50? And Steven Word wants me to not say anything and "just let people think that". Bull. Notice the site doesn't say "Not anywhere as good as a flatscreen TV, picture dim and fuzzy around the edges, but watchable." It doesn't say "If you can afford a flatscreen TV, use this because it's better than nothing". It says the devices GIVES A GOOD QUALITY IMAGE AS SOME $1,000+ FLATSCREEN TVS FOR LESS THAN $50! If that ridiculous claim were true, flatscreen manufacturers would simply go out of business. Use common sence, people. Anybody that GIVES MONEY to these yahoos that run sites like ProjectBig.net, WebTV100inch.com or any of these other sites is a SUCKER. Plain and simple. |
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Gadgit Unregistered guest | yip just another shammer selling fresnel lenses and calling them devices?? whats that about |
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Steven Word Unregistered guest | When are you going to start comprehending the stuff you read instead of immediately retorting? I never said that these sites were right. I never said the fresnel projectors rivaled the thousand dollar projection tv's, hell, I even agreed that the fresnel lense projectors do NOT compare to the LCD projectors. So what do you keep pointing the same point out for? We know they aren't as good, that's why they're 10.00! Get over it! What good is it to act like a broken record? It isn't your place to make up the minds of people who for some reason seem to think the quality is great. It isn't by any means terrible for the price, but it isn't that of a 1000.00+ plasma tv. When will you see that i've agreed with you on every point? Don't direct comments at me, and hope that i'm reading. There's no point. If you had a site selling these lenses, you aren't going to blatantly say "these 'kits' suck. Don't buy them." You as an individual, as well as myself, would probably not claim what others have, but this is America. What does America care about? Money. To get money, you must SELL by whatever means, and if that's their method of selling, FINE. Now, there seem to be two types of people which you immediately classify as "suckers". The customers of these sites that "give money to those yahoos that run sites..." are not all suckers. I for one KNEW what I was getting. I had seen one in action before I bought it, and I was impressed with the <10.00 price it carried and thought it'd be a cool thing to show my friends, and it is, they all love it too. They've all agreed with me that the quality isn't the best, but they also agree that it's a nice alternative for someone who doesn't watch many movies and who doesn't have 4000.00 for a plasma screen. I will say again, if you don't think people should buy these, that's all nice and fine, but don't make them out to be suckers when half the time, people are smart enough to know they aren't getting a high def. television, and anyone would know that for 10.00. These people buying the kits are not in any way hurting you, so why care? Live your life and let them live theirs, after all, it is their money. |
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Gadgit Unregistered guest | You have some good points but even though you knew the image was'nt that good why did you buy the lens from a sham site when you can get the lens for $1.95USD on ebay and the plans for free on the net, this is the whole point Motley and myself are making these sites sucker ppl in by saying the image is as good as a lcd projector. and that is what this thred is about "100" projector for $9.99 should I or should'nt I" the answer is no, not when you can get the lens for $1.95USD and the plans for free and also not if you expect a clear image from this fresnel lens. Steven Word take a look here http://groups.msn.com/diyprojectiontv/_messageboard.msnw these guys will point you in the right direction to get a better image from a DIY projector. |
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New member Username: MotleyPost Number: 12 Registered: 12-2003 | Geeze, somebody out there is ANNNNNGRY at me! ha ha, now that's a hoot. Steven Word, the only thing I question about what you suggest to me is that I should essentially shut up and "let people think" that fresnel matches up to LCD if they want to. I question that. This is a forum for open discussion. It's not for anybody here to suggest that anyone else shut up and get a life or for one person to wonder why another cares. Know what? I'm not going to shut up and get a life - I'm going to keep speaking my mind. So, I guess you'll just have to deal with it. Why not direct your ire at the scam sites instead of me? I'm not the one out there ripping people off. If you scroll up, you'll see where I admit that you and I are having two different discussions. I have accepted that you make your peace with the limitations of the fresnel system. I say fine, "have a coke and a smile". Then I point out that MY beef isn't with folks who build for free, but with scam sites making these snake oil claims. (To make THAT point, I pasted ad copy from PROJECTBIG.NET that claims their system rivals and $1,000+ flatscreen TV.) All that said, if you still choose to patronize a scam site with both eyes open, that's your money and business. But, a lot of people may unknowingly get suckered in by these smoke-and-mirror testimonals and that's where (in my humble opinion) THIS BOARD owes them the honest information about it. Yes, it may be the American way to sell by any means possible, but I say QUESTION WHAT YOU SEE IS WRONG AND LET PEOPLE KNOW. Then they can make an informed decision. The fact that people getting scammed is not hurting me is not the point either. Sure, we could go around and around on that point, but I'm not going to defend my right to post on an open Internet message board. Others post with impunity and so will I. So, I don't care that you may disappove of that I'm busting out these sites or that you may take it personally that I call scam site customers suckers or frankly about much else you wrote. The only thing I take issue with is your saying (to me): "If you KNOW the results of a fresnel projector aren't as good as the LCD, then why even bother replying to the post by someone saying it is? Just let them think that." But, then, why get mad at me? Using the Steven Word logic, if you KNOW that you aren't a sucker for patronizing a scam site, then why bother replying to people who implies scam site customers are? Just let them think that. |
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Steven Word Unregistered guest | Gadgit, I didn't buy it from a site, I bought it from ebay for 2.00. Stephen - I'm far from angry. You seem to have forgotten that you asked me to answer the questions you asked me that invoked me to speak about those sites, and when I do, you "try" to throw a smart comment about "using the Steven Word logic...". How many times are you going to double standardize the posting here? To quote the great Mr. Holmes, "You admit that fresnel doesn't match up to an LCD and you make your peace with that. FINE! No argument there. If those are your standards, (like I keep saying) "have a coke and a smile". Nobody cares." Oh, nobody cares? By that, you're implying that we shouldn't post that opinion, because obviously if nobody cares, it shouldn't be said? So what's different from that comment and me telling you to let people think what they want? Absolutely nothing. You're right that we're defending two different ideas, but the reason we're doing so is the same, because we feel the people should know. You feel that they should know it isn't great quality at all, and I feel they should know sure, it isn't great quality, BUT for the price they pay, the quality is watchable. When you say to "QUESTION WHAT YOU SEE IS WRONG AND LET PEOPLE KNOW", the inverse of that is also true, Accept what you see and let people know is right (or in this case, GOOD) about it. You're displaying your stubborness and closure to opinions and discussion by not caring what I wrote, if you didn't care, you wouldn't have spent 10 minutes writing a paragraph-long rebuke, now would you? Right. |
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New member Username: Bigbear777Post Number: 5 Registered: 12-2003 | Great device! |
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New member Username: Bigbear777Post Number: 6 Registered: 12-2003 | Got mine here www.webtv100inch.com Cant complain with my personal results. I used a 22" flat screen TV. Great picture! |
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New member Username: Bigbear777Post Number: 7 Registered: 12-2003 | I achived 100" without much of a loss of picture quality. Great project! |
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Gadgit Unregistered guest | Sorry steven I thought you got it ftom one of those sham sites I appoligz |
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New member Username: MotleyPost Number: 13 Registered: 12-2003 | Gosh, Steven...can you possibly post a response without defining me and my reality for me? How do you know so much about what I forgot, what I'm trying to do, what I must be implying, how "smart" my replies are, that I'm stubborn and closed to opinions, or the "reason" we're discussing two different issues? In my opinion, this kind of erratic know-the-other-person approach has nothing to do with the topic at all, but ventuers into arguing just to argue. I leave you to do that by yourself. When you want to discuss this board's topic, let me know. But, bottom line is I will speak my mind regarding the subject matter of this board no matter what you or others say. Sorry if you're taking issue with that (if you are), but there it is. Now, to Big Bear...tell the truth. All you get from WebTV100inch.com is an ordinary fresnel lens, and a xerox book of "plans", right? If not, what's the BIG SECRET? If you don't want to post what you get from WebTV100inch.com for all to see what the BIG SECERT is, why not? |
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New member Username: MotleyPost Number: 14 Registered: 12-2003 | S. Word, yes, I did invite you to answer two questions. You answered them, I acknowledged that you did, accepted that we were on two different pages and further clarrified my approach to this discussion with the ProjectBig.Net example. Where the train veers off the track (for me) is when you wondered why I would reply to those who make what I feel are dupious claims. I told you it was my general right to do so and received in turn what appears to be a pretty bombastic reply full of strange implications and accusations on a personal level. Tell you what...let's agree to disagree on the fine points of our discussion and part ways like gentlemen. Then you can go back to discussing the best way to build a projector and I can focus on the listed topic of this message board. We can simply leave it at that. |
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New member Username: MotleyPost Number: 15 Registered: 12-2003 | And, one last thing... To correct the response on my statement "Nobody cares." Word says: "Oh, nobody cares? By that, you're implying that we shouldn't post that opinion, because obviously if nobody cares, it shouldn't be said?" Nope. I'm only peitioning people like Big Bear for more information. What good is it to keep on posting nothing but: "I got mine from WEBTV.COM! Works great" over and over and over. Fine... We know where you got it and who cares? Now, how about discussing WHY and HOW it "works great"? Put the details on the table so we can discuss the subject of whether 100 inch projection TV for $9.99 is worth it. That was my point. |
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Gadgit Unregistered guest | Look at this sony took the idea and put a real lens in it http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3073623533 |
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CyHunter Unregistered guest | Three words: Why the hostility? I mean, sure, an LCD projector is the ideal choice (duh), but they cost hundreds of dollars. For TEN BUCKS, I hardly see how getting your TV image to increase in size a half-dozen times can be called a scam. With a little elbow grease, it can be a fun little project and provide results at least worth the ten stinkin' dollars. I ordered my lense and anxiously await getting started on my projector. |
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Gadgit Unregistered guest | The reason it is a sham is the images showen on these sites are from LCD projectors and not from a projector that was made from a fresnel lens and 14"tv the image you will get from any of the plans you will recive (witch by the way you can find for free by using a serch engine ie google) will be dark and hazzy it is watchable but can give you headacks. If you serch ebay you will find the lenses for $1.95USD this is why it is a sham. But the idea works you can get a good image but it will cost a little more to setup with a good 100 to 150mm pcx or pmn lens witch can be found at http://www.surplusshed.com/ the lens will be around $6-$8 these lenses are glass so the box will have to be made out of wood of something that will give a bit of suport if you do it right the image will be as good as a LCD projector with a good focused and sharp image but it will still be a little darker then the $2000LCD as the lums comming from the tv are only around 500 I built mine for under $90USD incluiding the high gain silver screen I made to up the brightness. |
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Anonymous | I tried this a couple of years ago. It's a piece of garbage. I now have an Infocus X1 DLP projector combined with a nice high gain silver screen and the quality is fantastic. Save about $850-$900 and get yourself a X1 DLP on Ebay from a reputable seller, then buy some Silver PVC fabric and paint the front with a couple coats of clear matte laquer (and there is your imitation SilverStar screen which BTW, costs as much as some pretty good projectors). It'll give you a much better picture than any DIY projector. No hassle. I noticed some people mentioning the great screenshots posted for the 100" TV. PUHHHLEASE! I am a member at AVSForum and I can verify that most of those screenshots are hijacked from real projectors ranging in price from $1,000-$10,000 (and CRT projectors that cost upto $30,000 when they were new). You CANNOT get a picture like the screenshots they provided by using your tv as a projector. That's a fact. The picture sucks and will be very very dim. If you try the project you will need to get a translucent painted silver/white/grey combination screen with mylar mirror backing to even be able to get a somewhat bright image. |
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New member Username: MotleyPost Number: 16 Registered: 12-2003 | CyHunter...you ask "why the hostility?" How is anybody being "hostile" by simply reporting the truth? $9 projection TV is crap. That's just the way it is. Gadgit just spelled out why in spades. Do you regard his post as "hostile"? Frankly, we have a right to call a scam a scam and if you think that's "hostile", too bad. |
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john rastelli Unregistered guest | anonymous, The site that i bought mine from was www.projectiontv.co.uk, the guy who runs this site was very helpful in getting it up and running. I have now got a projection of around 70 inches for the few quid it cost me. I'm not gonna tell you that it is better than a projector that costs a lot of money. and the picture is dim, and yes i need a really dark room to watch it in. but it is entirely watchable, i even project my photos on the wall that i have taken with a digital camera. It is definately a case that you get what you pay for, however for the 6 quid i paid for it, its definately one of my bargain buys, and there is no way i could call it garbage. and the pictures that he shows oin his site, are real screenshots and not fake, as i can vouch that i get that quality with my projector. so to sum it up, it ain't an all brilliant projector that i have seen some people claim, but if you keep your expectations realistic, then it is excellent value for what you can get. John Rastelli BTW i am not a person that sels these lenses, if anyone wants to ask me more questions about this project, then you can mail me at john.rastelli@italianlacrosse.info |
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mooga2000 Unregistered guest | Hi - Does anyone know whether it would be possible to do this with a laptop - or would it just not be bright enough? |
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to55a Unregistered guest | it wont be bright enough unless you dismantle the screen and remove the backlight and then you add a bright light source behing the LCD screen. |
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Gadgit Unregistered guest | Hi mooga200 if you strip the back light from the rear of the screen like to55a said and put the screen on a OHP then you will have a very large screen computa on your wall many people have done this and it works well |
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Anonymous | Mortley is a f*cking f*ggot |
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millionknives Unregistered guest | gooooooooooooooooooooo gadit lol he should kno me anyways.. ima say this: no its not worth it 100.00 projection yes worth it and works but 9.99 uh no.. wont work tried the frensel lens sure if you melt it had to use six lens till i got it right so that it works with the curved screen then its over all same but still blured as its plastic and not glass. now say somehow you get the perfect glass lens sure its nice but with curved screens nope. and even with flats sometimes its not gonna work. now if your really diy and want a good one go lcd diy please youll get really nice results (ya not as good as 2000 ones but close as its not as bright unless you get a nice white light thats strong and build a custom housing box) all in all if you dont do lcd do flat screen and not frensel (ie page magnifier its good for expermenting but not quite good enough i was obsessed with perfecting those things) use a beta 2 should be nice. http://groups.msn.com/diyprojectiontv/messageboard.msnw gadgits there im there prof there get all the info you need there but back to the topic quistion: 100 inch projection tv for $9.99? Should I or Shoudnt I? no. wont work gotta be more expesive say 100 flat screen or lcd (ill take lcd as its smaller in the long run but may have to replace the bulb in your custom housing but much cheaper then 2000 and works nearly as good) like i said go to http://groups.msn.com/diyprojectiontv/messageboard.msnw and 9.99 aint going to cut it. ..EVER.. |
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JohnnyBravo Unregistered guest | hi gang...i read your posts AFTER i bought the fresnel lens and i wish i read them b4 i did!! I made up the box with the plans i got and no matter how hard u try to make it near to perfection u can get...the image i recieve is very blur and distorted...so......it looks like i'm going on ebay to see if i can buy a lcd projector for a good price..if any of u guys can help me out with the fresnel idea let me know....hopefully i can correct it untill i get my lcd projector cheers johnny |
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sinflrobot Unregistered guest | I think the brightness issue could be rectified by using a 15" lcd ($200 us) and adding much stronger backlighting (probably needs cooling too). If this was combined with gadgit's lenses, what would the results be? I'm thinking it would be a project that would costs under $300, be plenty bright, and hopefully gadget's lenses (rather than the fresnels) would fix the edge distortion. Any input? |
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New member Username: StationbellPost Number: 1 Registered: Mar-04 | Motley- Who died and made you GOD of this board? I think you need to go to a board where you can run it. As you put it "WHO CARES" what you think!! GOOD GOING BIG BEAR. |
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Bronze Member Username: MotleyPost Number: 17 Registered: Dec-03 | Gee whiz, first I'm called a "f*cking f*aggot" and now I'm called "GOD"! I'll graciously accept the promotion! Ha ha! |
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millionknives Unregistered guest | uh had you read "Who died and made you GOD of this board" you werent anyways the lens alone for a half decent projector is going to be about 30 (thats with shipping and handling) then the supplys to make the projection box then the screen so its NEVER going to be less then 10 unless you go to some acution and find it all for 10 and meraculisly win which is nearly impossiable. as for the lcd brightness problem, using an overhead projector as the light source and dismantiling it and taking out the lighting system, and the projections lens and making a new box so that the lights first then the lcd then the lens, while its light tight and using a cooling system will indeed improve it drasticly, however you may have to sit down and think about the design and may end up using a mirror system for the lighting so that the light is used but you dont see the light system in the projected image. using a design a little like this would work http://groups.msn.com/diyprojectiontv/collectedpicsfromsites.msnw?action=ShowPho to&PhotoID=104 however, the mirrors and light placement may need to be changed so a lightbulb outline isnt seen that would make it look unprofessional and be VERY annoying (i tried it with a laptop nice but a bulb outline sux) there is a ok try for the frensel problem johnny, go to http://groups.msn.com/diyprojectiontv/general.msnw?action=get_message&mview=0&ID _Message=6383&LastModified=4675465196314231824 and you can attempt however dont force the lens to bend as you try this as it will snap i did snap two be4 i got one to work but it may take a while i used an older hair dryer and it was quite smaller and not as hot as many new ones tend to be. this will get it unblurred on the edges but as the pictures going through plastic you will always have a bit of blur and sometimes a halo effect. its rather good for first few projector "experments" but youll get dissatified after a while and want clearer pictures. i still have a page mag setup in my bros room as he doesnt care much and it is quite nice but im probely going to go with a glass lens for him. so try it out on the page mag, as for the lcd get a panal that is in good condition and try to get one with the cords and remote and the manual but if not and it has everything else and says it works you may want to try it. and sinflrobot the lighting thing is up in this post and this is using a similar lens to gadgets(BUT NOT THE SAME SO DONT QUOTE but close!). once you use a good glass lens compared to the frensel youll want to never go back but frensesl can give good results if you get obsessed with it like i did but it will never be as clear as with a glass lens as its plastic. hope this helps out. |
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Bronze Member Username: MotleyPost Number: 18 Registered: Dec-03 | Frankly, I'm glad I'm being singled out for (as CyHunter above says) "the hostility" that he claims comes from those who do not support fresnel lens TV. It means that (though some may not want to admit it, wink wink) people do "care" what I say. Otherwise, why bother to comment on my posts? But, if you yahoos scroll up, you will read that I claim over and over that while in my opinion fresnel lens TV is crap BECAUSE you can get the same thing from an internet download instead of handing your money to an e-bay scammer I do not say don't build it at all. Built it if you want to build it. Why would anybody care? You're the one who has to watch your contraption, not me! In fact, if you want to go ahead and petition scam big screen TV site, have a coke and a smile. It's your money. So, people like Cindy Esep and Big Bear can attack me all they want. I'm not small enough to give a hoot in hell about some faceless person out there hiding behind their computer spewing insults rather than discussing this topic. However, one post like JohnyBravo's above carries more weight in my book than a hundred insults from the likes of Cindy Estep and Big Bear. So, my many detractors, get to drinkin' and typin'! If you want to insult me and put down my posts, have at it! I will just keep on discussing the topic and posting my opinions here just like everyone else. So sayeth the God Of This Board! :-) |
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Yattan Unregistered guest | I checked out the site that Gadgit had supplied a few posts up for lenses. I didn't find the exact ones he was talking about though.  Could someone point me specifically to good glass lenses to use. I'm planning on trying on of these for my kids to watch cartoons on, nothing more.  Also, any tips on simple ways to improve clarity, focus, etc.. would be appreciated. |
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millionknives Unregistered guest | ya one NO FRENSEL..EVER.. not good for clarity as for the screen you want a silver type or you just cant get the best light reflection which means its dim in english the setup i have is SUPER clear like you cannot belive however my screen isnt silver (the one im using) as the silver one isnt done as im doing a hit and miss on screen material sure the paint is good but it needs the screen matieral to be PERFECT however the one im using is suffiecient its the normal white. the lens has to be a glass one period or it will as stated earlier be really nasty if you get any were over 60" in size with my experence of the frensel land. the box needs to be painted black on the inside as it helps keep things clear (yes some paint it white but it gets blurry so just use black) the setup im using now is a curved tv and like i said its REALLY CLEAR its the screen it projects on thats an a$$ as its not bright enough for hardcore gaming but if its for movie or tv then its perfect. |
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millionknives Unregistered guest | o btw yattan email me with your email at millionknives__@hotmail.com and ill make a little guide and tell what lens setup im usin with pics so that you can make a good diy projector witthout even opening the tv and the words are actully correct and not backwords! and any one else that wants to can but once i get like 10 emails ima just put it on the web and send a link back and make sure to label the email as "diy projector" or ill delete thinking its spam. |
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Anonymous | i made a projector out of a card bored box, a mirror and a 14 inch. tv. the image is HUGE from a 10 ft. distance suprisingly clear and even kinda sharp. i tired using a 20 inch flat screen , it gave me an awesome picture, i wonder why soo many people are not happy with their results. i used the tv on back ,box on top and a mirror to reflect the image on to the wall. it worked really well until i got pissed off and destroyed the box..i have a short fuse and a really hot temper..i got frustrated and just completly tore it apart... woops...anyways, i still have the smaller box projector, i plan on making another one for the 20 inch flat screen.when i am not rushed or pissed off. the first one i made for it ( the 20 inch tv ) it seemed really clear and it was focused and even bright.yet it was only 10 feet away and the image was 11 ft. by 11 ft. it was fun and all.....but i have no patience or time . i am gonna buy an infocus X1, dlp projector and use a fresnel lens in front of it to further insrease image size. i totally respect you all who painstakingly pursue the quest for the perfect image and the perfect projector, i tried it but i simply have no patience...it's too bad, because the image size was simply awesome!!!!!!!!!!!!!! also,has anyone tried using multiple lenses at the same time? |
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cse90 Unregistered guest | in 1985 when projection TVs were still in the begining stages of developement and befor lcd projectors were on the market i built a projection tv from cardboard and a fresnel lens and it worked fine in a dark room i made the lens adjustable so i could focous it and the picture was good but true not as good as an lcd projector , i can say that for a few dollars you get a great education on optics |
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SPARTAN907 Unregistered guest | i highly recommend doing the tv on back projector on top and mirror at 45 degree angle, with a 14 inch tv, i got impressive results at 10 ft. away, got the full 150 inches on my bedroom wall, i don't see what the big deal is.. the picture may not be bright or sharp, BUT IT IS PRETTY DECENT,but i think that this can all be fixed by using a bigger tv, this should increase the brightness and sharpness by at least 50 %, making it entirely viewable.crank up the sharpness, color and brightness and it WILL work, i love this thing!!!!once i get a bigger tv i will share my results. i highly recommend this projector set up....i just wanna get this working so i can impress girls..thats basiclly it, and when she says out loud "my god , it's SOOOOOOOOO BIG!!!!" what can i say? "yes it is ma'm..yes it is!!!!!! OOOOH YEAH!!!!!! |
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SPARTAN907 Unregistered guest | i give up.i tried the 20 inch. flat screen, with the tv on back projector on top, mirror reflecting image.image was way to dim, not viewable, awesome size yet with no real viewability or any clairty. worked better with 14 incher, yet picture was still too dim.... scrap this idea, i'm on my way to buying an infocus X2 the newer model with a stronger short throw lens.not the one to diss on frensel lens or the idea, it's an awesome concept with a million dollar potential for whomever has enough time and patience to perfect it , it will be a goldmine in sales. good enough as it is, it could be better, once it is...i'll buy some. until then,i'll stick to power lifting,eating , and of course..beer. good luck to all of you. |
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johnnybravo Unregistered guest | I've just bought an amazing DLP projector on ebay for a snip at what they go for..( i feel like i've robbed him)...and i'm hoping one of you guys could help me out b4 i get my screen...what could i make a good capable screen out of? |
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TechNOFreaK-@ 213 Ca Unregistered guest | you can get an infocus manual pulldown screen at crutchfield.com for only $199. why make one out of cheap material when you can just save yourself the hassle and frustration.i too am gonna buy an infocus projector, i heard that they are one of the best types to buy for movies.tried frensel, but i think that it's still in it's rudementary stages of development. but , i predict that one day they will be the next "craze" once the concept is fully developed and flawless. |
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too bad... Unregistered guest | picture was way too dim, pretty clear and was 150 inchs, but still too dim to watch a whole movie. |
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lil' GLOCK-213 Unregistered guest | got me a tight lil' infocus x2 at a swap meet. it's the bomb yo!!!!!! slapped on a fresnel in front of it... got a big o 150 inch movie theater , no problem!!!! tight !!!!!! for shizzel my nizzel!!!! now i gets blazed up chillin while i got scary movie on my theater!!!!!! represent 213!!!!!!! |
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JohnnyBravo Unregistered guest | I'm sorted with a screen now....2.4m width , 2.4m drop.....wohoooo i'm sorted!!! |
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tv on the cheep Unregistered guest | LCD owners, quit crying! If the scam sites upsset you, sue them! If you don't care what the rest of us watch you sure seem to b**ch about it a lot. And in the final analysis it sure seems that a fifty dollar investment is much wiser than several thousand when appreciable viewing quality is not only possible but entirely probable given a little patience and time. OR are you afraid of losing employment with or a comission from mitsubishi or RCA? Here's the box of kleenex by the way... |
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hi Unregistered guest | i tried this and it is really dim and blurry, yep, thats about it |
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Unregistered guest | i am intersted in building the lumenlab lcd projection tv. has anyone here tried it? or have any ideas for me? |
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hazz3000 Unregistered guest | i built a projection tv with a normal 14" tv. It wasn't an amazing quality shot but it was fine. It was only bad around the edges. If you want lens and plans go onto ebay. Plans are selling for 99p so might as well what are you losing. |
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Bronze Member Username: Jdsaenz1Post Number: 25 Registered: Jun-04 | Man, millionknives! How 'bout going to grammar school before you post, bro? |
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Anonymous | AWRITEY TROOPS i tried da projection tv last week AMAZING RESULTS all i did was get a carbord box paint it black put the tv and peu fresnel lens on the front , at the start the image was kinda blurry but a came acroos aaway to beet the blurrieness round the edges all you do it cut out 2 carboard rings and place them at either side of the fresenl lens WELL WORTH IT IN THE END btw the way if u r annoyed about my spelling or use of language ( words not swearing ) forgive me am a 13 year old scottish boi HEY waht daeu expect from me LOL |
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Anonymous | spelling mistakes from above *what *put *away |
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DUDE4534653 Unregistered guest | THERE IS A WEBSITE OFFERING THIS KIT FOR FREE. I GOT MINE AND IT WORKS PRETTY GOOD. ALL I HADE TO PAY WAS A SMALL SHIPPING CHARGE OF $2.99 WORTH THE PRICE! http://www.webtv100inch.com |
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PROJECT_REALLY_HUGE Unregistered guest | Funnnnnnnnnny. I came across this paid google ad for the 10' tv for $19 and was a little intrigued by it. I figured it was a scam but had wondered for years what would happen if I put a fresnel lense in front of the TV or used some mirrors or put a small TV upside down on an Overhead projector. (Essentially the same thing so now you know how damn dark it needs to be and how bright your lightsource needs to be). I googled "projection tv scam" and wound up at this forum. I also searched the BBB for the name of the website that was selling the plans and they did not have an unsatisfactory record. I suspect for $20, people assume they just didn't do it right and aren't pissed enough to complain. Same with ebay. They just didn't know. Anyway, I enjoyed reading this post for the last hour. I guess the debate has been going on for months. I commend Motley or Stephen for pointing out the unrealistic claims even though it seems his cheering section is much smaller than projectbig.net which is now featuring weight-loss pills. Hmm. From once BS scam to the next. |
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nonya Unregistered guest | I wanted to know more about the whole build-your-own-BSTV, and now i do, and the content on this thread was awsome, however the fighting really pissed me off, the ones who faught should feel imature and and ignorant, the ones who wanted to learn, like me, had trouble doing so cause of you people, this really was one of those cases were mom's right when she says "IF YOU DON'T HAVE ANYTHING NICE TO SAY, DON'T SAY ANYTHING AT ALL", lol, don't respond to this message or else your a flamer who is comming out... and you like dog weiner...big dog weiner, lol |
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Unregistered guest | here is basic plans on how to build an lcd projector! materials 1 lcd screen (2.5 inch workes good)$25-$75 2 cpu cooling fan $2-$8 1 halogen light bulb $6 1 glass mirror $2 1 ducktape roll $2 1 cardboard $priceless 1 lense (2x fractel $6 - 10x camerah lense $30) box build with two compartments one for the light to the back of the lcd screen and one to point the image threw the lense onto your screen note:you have to bounce the light of the mirror to the back of the lcd or else it gets to hot note: you will have to take apart the lcd screen the light that comes with it isint bright enuf to creat a good picture so thats why u use the halogen but it gets hot thats why you have the fans. my first attempt i used a 500 wat halogen flood lamp from my gurage and lets just say it dint work after that i couldent even take the lcd out of the box melted it together! |
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Lord_Nikon Unregistered guest | http://www.lumenlab.com |
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Bronze Member Username: MotleyPost Number: 19 Registered: Dec-03 | First, let me point out 2 things: 1.) You can get a fresnel lens at a store like Office Max; and 2.) LCD projectors are now being sold at stores like Staples and Sam's Club for as low as $800. I bought mine for a tad over $1,000 some time ago. So, the prices ARE dropping and you may want to take that into consideration. That said, it would be interesting to hear what fresnel lens supporters have to say about Lord_Nikon's post (directly above mine). I have to admit that this lumenlab system at least looks like it has SOME chops. But, what is interesting is that (for all you folks who keep claiming to have gotten AMAZING results with your upside down TVs), the lumenlab ad states: "WARNING: Many internet sites are selling a cheap plastic fresnel lens and claim that you can 'project' a television onto a wall and get a cinema experience... Don't believe it, the picture quality is awful! To build a video projector you need real optics, real science, and a real bright light!" Hmmm. Lumenlab says fresnel TV blows! The plot thickens! Are we in for a battle of the scammers on this site? Stay tuned! |
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Bronze Member Username: MotleyPost Number: 20 Registered: Dec-03 | Elliott Ramos - Before I bought my LCD projector, I tried your idea (which appears to be the same as the lumenlab plan). I got a huge image, but problem was that the pixels on my 2 inch LCD panel were also enlarged. The picture was grainy as hell becuase a 1 or 2 inch LCD panel isn't manufactured to explode out to 10 or 12 feet. It's made to be viewed at that 1 or 2 inch size. Let's say you download a small jpeg on your computer and it looks fine. But when you start zooming in on it, the bigger it gets, the grainer it gets. So, for those wanting to try your idea, how do you get around that? Or do you just accept that your picture isn't going to be that sharp? |
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Gadgit Unregistered guest | Just to throw another worm in the bucket.... Fresnel lenses do suck but the IDEA works you need to have a good lens to get a good image and after that the screen has to do the rest of the work...you cant just use a wall like the shammers say it has to be a screen of very high gain. CRT projectors are the best quality and the most expensive but a CRT is just a TV so goes with out saying a home made projector made from a 14" tv, a good 150mm+ triplit lens and a very high gain screen does give good results. But if you have $800 or so to spend and a few extra $$ each year to replace bulbs, may as well buy a lcd or dpl on ebay. It is a shame people sell the fresnel for something it is'nt cause more people could have afordable big screen tv's for a few $100 if they did some reserch and enjoyed building stuff. This is not a project for a person who wants 150" tv on there wall in half an hour. |
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slayer6616 Unregistered guest | hi there im new to this hole thing with big screen tv building,,i bought a fresnel lense and built a box which i atached to my 15' monitor turned it up as bright as it would go and set the lense up and got a pic on my wall it was a huge picture but it wasnt very sharp,now i wasnt really expecting much as i only payed 10$ for the kit,but the whole idea is a good 1 and i want to take it further,im looking at building a lcd projector using a small in car lcd screen maybe,now could any 1 please direct me to a site or to some one who could give me good proven plans and parts to building a lcd projector that would be great!ive been scaning the web for a few weeks now and cant really find anything of real use only heaps of people selling those fresnel lenses claiming there amazing and all the rest of it,any help would be great as im running out of ideas for this project thanks! |
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Gadgit Unregistered guest | http://www.diyaudio.com/forums/showthread.php?s=&threadid=21892&perpage=10&pagen umber=1 try this link look for ace3000 this guy is a member of the diyaudio group and has made some nice lcd projectors. |
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Unregistered guest | Well, that was a LONG thread to read through. As a new big screen TV fan, I'll throw in my two cents here along with some scientific reasons why a "cardboard" projection TV works as it does The whole idea of building a projection TV with a lens, either fresnel or magnifier, is intriguing to my engineering side, and I'll probably do it just as a fun project, and experiment with it to make it work better. The basic concept is something I've seen in other forms, like overhead projectors and opaque projectors, and if I can get one or both of those at a school equipment auction, I might try something with them. The science behind it is easy to understand, since I have some background in optics, light projection, etc. For those who are wondering about some of this, the fresnel lens (or magnifier) merely takes the TV image light. which is mostly scattered, and projects it into a series of straight lines (putting it simply) that then form an image on the screen or wall. A fresnel lens is simply a magnifier (magnifying glass) that is "sliced and sectioned" so that it doesn't have to be so thick and heavy. Sorry, but it is a hard concept to follow unless there's a diagram to help show it, and I can't draw that here. However, please take my word for it. To help in understanding the "cardboard" TV, Imagine that the fresnel lens is the lens of your eye, and the wall of the TV room is the retina of your eye. On the retina of your eye, the light image is also upside down and reversed, but your mind works so as to "flip" it over and correct the image. Adding a second fresnel lens or magnifier repeats what the first one did which is to "flip" the TV image again so that it is now correct. Now, if your eye's lens does not focus light onto your retina, you need glasses. What you have then is a "second" lens that "distorts" the light in such a way to help it to fall into focus on your retina. A second lens on a projector TV would do this too, and you simply have to be able to move it in relation to the first lens which would be fixed. Of course you can instead arrange a method of moving only the first lens and get the same effect for focus, but you still have the upside-down image, so 2 lenses is a good way to go. Also, the reason why the inside of the box is black and not white is because white reflects light in all directions and does create a "wash-out" effect. Black does absorb light, which is really what we want here because it is absorbing the light that does not get directed to the fresnel lens anyway. So that's the answer to that question. In regards to the fuzzy edge problem, that's caused by using a TV with a curved surface, and projecting it onto a flat screen. The light from the TV's edge has to travel a tiny bit farther and, hence, it is out of focus. This is why a flat screen TV works better. About the brightness of the image, think of the amount of light coming off the TV screen itself being spread out over an area that's maybe 10 times as large, or more, as the original screen, and you can see why it would be dim. The TV itself was built to be viewed directly and not projected, so there's no way to expect wondrous brightness here. However, here's where the size of the TV itself is a factor. It isn't true that the optimal TV for this is a 13 inch. That's only the easiest size to handle, that's all. In fact, the larger the screen size of the original TV, the better for the projected brightness. After all, a 20" does put out more light than a 13", and a 25" or 27" is even better, but then they are harder to handle. However, a desktop 25 or 27 on a rolling cart would probably be feasable. The matter of going with a screen or wall is easy, the best is whatever reflects the most light in the most direct way. A very smooth pure white wall will do well, but again here's where a school equipment auction or warehouse or even secondhand thrift shop can be handy. Just buy a used, good condition, movie screen or dig out that old super-8 movie screen of the folks. They are designed to reflect projected light best. They have special surfaces that can double the light reflection of a plain white wall. In fact, they are almost silver, or silver-white. One last thing, I have only recently become a big screen TV owner, having been satisfied with a 25" set for over 10 yrs. I found a really good top-line Fischer 40 inch 1984 model that was well kept for only $200. That was 2 yrs ago. Since then, I have bought 2 other second hand big screens for other rooms, a 36" 1988 Mitsubishi for $100, a 48" 1996 Mitsubishi for $600, and all of these are beautiful TV sets with wood cabinets and all were well maintained. I'd suggest going that way if you can't spend a lot, and doing the "cardboard" TV as a fun exercise, or doing it until you can afford something else. In my opinion, whatever you can do to make your TV viewing more enjoyable and pleasant is great, even if it's a $20 cardboard home-made projection set up on a $100 flat screen with a $39 DVD player from the Wal-Mart. Hmm, that's almost the price of my first big screen (which I have on right next to me at this very moment). |
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rixrex Unregistered guest | By the way, I forgot to mention that what you have built when you build a "cardboard" projector TV is the "inner workings" of a rear screen projection TV. If you were inclined to also build a large cabinet, and you located a piece of opaque screen material somewhere, or some sort of opaque plastic that would work, you could seal your TV and lens someway at the front bottom of the cabinet, bounce the image off a mirror at the cabinet back, and place an image onto the screen material. Not really as easy as it sounds, but it gives you the idea of how the whole thing works. I have found broken down second hand components often cheap to buy and good for these kinds of experimants. For example, the cabinet, mirror, and screen could come from a rear screen set that doesn't work and somebody just wants to toss out. Also, for those looking for wall screens, old movie screens are great and can be pretty cheap since nobody uses them anymore. Or if you find one of those very first projection TVs where the screen was a curved rigid silver panel set in front of a projector, that would be great to take care of out of focus edges. Just throw away the old projector TV components and substitute yours. |
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Gadgit Unregistered guest | Rixrex Just a few points.. A 14" tv is said to be best not just because it is easyer to handle but because the bigger the tv the closer to the wall it has to be. This would put the projector inbetween you and the screen not always the best if your seating is low to the floor. Also the more lenses you use the less light output so one lense is better and the yoke wire flip is not that bigger job to get the image the right way up. Have a look here there might be something of interest on screens http://groups.msn.com/diyprojectiontv/general.msnw?action=get_message&mview=0&ID _Message=8503&LastModified=4675485829131610804 |
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rixrex Unregistered guest | In reply with sincere regards to your quite valid points, the distance to the wall is also relative to the distance of the lens to the TV set and is adjustable accordingly. A larger set that is a desktop model would be possible to use and not get in the way, should you wish to do some experimenting with your construction. The additional distance of the lens from the set is a simple geometric angle formula that can be understood by taking the angle created from the lens (as point B) and angle rays extending to the top and bottom of the 13 or 14 inch TV screen (points A and C), then draw the rays out further to a point where a larger set can fit in. I have done this and found that, not surprisingly, a 27 inch set would have to have a box about twice as long as a 13 inch set to get the same size projected image with the lens at the same distance from the wall. Another consideration would be that the light will diffuse slightly as the projector moves further from the wall. It is true that 2 lenses would reduce light, a point I did not mention but perhaps should have, however if you were to use good clear lenses (such as magnifiers or ones similar to the lenses used in rear projection TV, there would be no discernable light reduction, and the benefit is the ability to control focus more easily. I suspect that the type of fresnel lenses available at the Office Depot for under $10 would reduce light moreso. I know that there are good quality fresnel lenses use in film/TV production on high wattage lights for directing and intensifying light, but have no idea if they can be had cheaply unless one was to come across a big sale of a defunct equipment house or such. They might be available from manufacturers as a replacement for ones that break in an otherwise good lamp. yet they might not be suitable for projecting an image as they are not meant for viewing through them. The way I would proceed to building one of these sets is to use a flat screen 20 inch set such as the inexpensive one another writer found at Wal Mart for $100. I might try my design out with a used 19 inch first. Then I would attempt to find good lenses from a second hand projector TV or from some kind of cheap used overhead or opaque projector. If not found, I'd use the fresnel from the office supply. I'd try it with one lens and then two, to see if the light reduction outweighed the focus control ability. I would also use the best quality used movie screen I could find, one of those silver beaded screens. The reason I like this type of surface is because it's made to reflect light optimally and directly so that there's very little light diffusion or light loss. An added benefit is that they either have their own stand, or can be hung on the wall, and yet are easily put away or rolled up. And they are easily adjusted to control any keystone effect there might be. If it all worked out, I might consider eventually moving up to a 27 inch setup with the TV set close to the floor on a roller device, and the keystoning contolled with the slight angling of the screen. I think it's possible to build a really good setup with a minimal of cost. In fact, if you use a more modern flat screen with S-video input and use DVD, or even laserdisc, you'll probably get a pretty darn good picture. |
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Gadgit Unregistered guest | A good lens is the problem you will run into as if you looked into the link I posted you will see that it is to a large group of people all over the world who are attempting to get the most out of this setup, the most sucsessful being Prof who is using a 150mm triplet lens witch I suplied him and he has developed a key stone correction and a very high gain screen of witch he can view the image with the room lights on well. The triplet lenses in RPTVs have a very short focal lenght and I dont think these lenses will focus a 20" tv screen as they have been found to only just focus a 13". Not trying to argue but dont want to see you go down a road all ready travled by many in the DIY Projection group. |
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TrailandError Unregistered guest | Hello there everyone...... Damn this was a long read. Some good pointers there. I too am having the problem with the edges being blurred and now i know how to fix it.I looked into some high quality fresnel lenses on the net the other day and ordered myself an arcrilic lense with a focal lenght of 200mm. My question is will the shorter focal length mean i will have to have the unit closer to the wall to get the same size picture? at the moment the unit i built is already painfully close to achieve the desired picture size of about 50". Have I just made matters worse by getting this lens? |
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Gadgit Unregistered guest | In short yes the focal lenght is far to short you need a lens like this http://www.surplusshed.com/pages/item/l3186.html Fresnel lenses are inferrior and you wont get a good sharp image from them. |
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TrailandError Unregistered guest | Thanks for the reply post gadgit. Wont this lens your suggesting give me the blurred edges? I have alredy tried a lens fron a magnifying glass and that blurred almost half the picture? Is it also posible to use a fresnel to concentrate the light and image on to a smalller lens or will that distort the image? Whats a triplet lens? |
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Gadgit Unregistered guest | A triplet lens is three lenses in a tube one focus's the centre of the the image the 2nd foces's the outter image and the 3rd focus's the whole image purfact onto a screen. The lens I have linked has been proven to give a good image with a aperture or tube on the end have a look here this guy is using the lens and has sone good results http://groups.msn.com/diyprojectiontv/kaosradiospcx14inchflatset.msnw |
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TrailandError Unregistered guest | Cool, I ordered one already and am waiting for its arrival. Would a triplet lens be even better than this then? I'll give this one a go and let you know how i went with it when i get it going! |
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Gadgit Unregistered guest | A triplet lens would give the best image but getting one big enough and cheep enough is the problem it needs to be 150mm or bigger and have a focal lenght greater then 300mm. Here is one the same as the one I have for $200+P&P US$ http://groups.msn.com/diyprojectiontv/general.msnw?action=get_message&mview=0&ID _Message=8884&LastModified=4675486920625441354 |
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rixrex Unregistered guest | To Gadgit, Thanks for the good info. Gives me a lot to consider before building one, and not getting too deep into the cost. It'd be silly to spend more than a reasonable big screen TV would cost anyway. |
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TrailandErrror Unregistered guest | right got the lens that you linked me to gadgit(not the triplet) and i works tops! I think i'll be giving it to someone i know though as I sold out and got a proper projector! Had lots of fun building this one though and i learnt a bit about optics thanks for you help. I would recomend anyone with a flat screen to get that lens as it is a very good picture compared to a fresnel and it only costs around $6 bucks US. |
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Unregistered guest | There is a lot of talk about using LCD's and flat screens. My laptop has a 14" LCD display, and plays DVD's. I can fold the display all the way back. What if I built a box that fits over the laptop lying on my coffee table, reflected off the mirror? I just bought a Fresnel off Ebay, and will start with it, then maybe tweak it with different lenses later. Anyone tried this yet? |
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Gadgit Unregistered guest | Xlthim the light output of a laptop lcd is not enough to project or any lcd but if you rip the back off the lcd and put a brighter backlight in like a 400watt MH bulb then you will get a good result but it's not a simple as it sounds. |
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Deetz Unregistered guest | After spending half the evening reading all of this, I am going to go for the gusto and build me a theater. I will try it with my 27" Pan. Tv first. I gotta kick out of reading all the opposition here. I'll keep you all posted. Bub |
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Gregert Unregistered guest | If these cardboard TV-projectors were any good everyone would have them. It's that simple. |
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Unregistered guest | Cardboard tv projectors are'nt anygood you have to put some effort into the project you cant expect good results from a plastic lens and cardboard you need a good flat screen tv a glass lens (not fresnel) over 100mm dia with a focal lenght over 300mm solid construction and a very high gain screen but check the sales of the fresnel sham theres a guy here in New Zealand who sucks 20 people a week into buying the kit and he is only one of many selling on www.trademe.co.nz in a country of only 4million thats a few and I only see two maybe three negative feedbacks on these people from over 2000 sales this shows people know you dont get much for you money and dont expect to. If you can afford to get a LCD or DPL projector get one I would get the DPL personaly but do some real resurch a sony vidimagic projector is just a strong CTR tv with a Triplet lens infront of it just like what I have built only the tv is not as overclocked as the sony,people back in the 50's and 60's had these projectors they just never took off because they would have been expensive then and now LCD projectors have taken the market because they can be built smaller and are more portable, the CRT projector is still out there but the cost is huge as they will projuce the highest quality image and you never have to replace the bulbs as there are none. But there are people who have good lcd projectors and are still building or tweeking there DIY setup because it is a great project. http://groups.msn.com/diyprojectiontv/_messageboard.msnw |
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Bronze Member Username: MotleyPost Number: 21 Registered: Dec-03 | With all respect, Gadgit, I have to disagree with you on a few points. Cardboard TV projectors aren't any good "because you have to put some effort into the project" ... they are no good PERIOD. Yes, they KIND of project a picture; you see a really big image. But, the picture is dim and blurry because televisions - upside down or rightside up - are simply not designed to project light. Televisions do not throw an image outward. This is just a matter of pure science, not folks like me getting on this board to argue. The middle portion of your post I totally agree with: there are scammers on the internet selling nothing but a fresnel lens and a xeroxed copy of "plans" for $20 or more. The very same "plans" you can download from this message board for free. Put the $20 you save into buying your own fresnel lens from an office supply store. Then, have at it. If you want to invest in this "fun" project, fine. Just don't help scammers keep beer on the table. And, yes, technology has grown leaps and bounds - the best part being that an LCD projector that would have cost $10,000 years ago can now be had for less than $1,000. They are selling them everywhere these days; at office supply stores, etc. Prices are dropping like a rock. I got my Sharp PG-A1OX Notevision for $900 and I LOVE IT. The downside is the price of replacement bulbs, but I can afford to live with that as the bulbs appear to be long lasting. Which brings me to another point: those that build DIY projectors simply can't affort LCD projectors, even at the new prices. Where is an average teenager with a part-time job supposed to get $900 to throw into a movie projector? How can a person on limited financial means afford to rip apart a perfectly good computer LCD panel to even take a whack at constructing a high end DIY projector? Yet, those that can't afford it still want a big screen experience. So, they are willing to live with the visual faults of fresnel lens projectors. More power to them. Just don't tell the world "WORKS GREAT!" In other words, don't go to a camera show and try to testify that your shoebox camera rivals a top of the line digital camera. This brings me to the second point where you and I disagree. I own an LCD porjector and would not think of "building or tweeking" a DIY setup. Why on earth would I bother when I've already got what I want? So, Gadgit, you have a lot of great and informative posts on this board. I'm not arguing with you. I'm just clearing the air a little for those who read these posts trying to decide if DIY is worth it. I say, yes, if you can't afford an LCD projector - just get the plans for free; don't make scammers rich. If you can afford an LCD projector - no, DIY is definitely not worth it. The picture on a good LCD is bright as day and sharp as a pin. To me, that is worth what I'm paying. The same quality can't be had - not even close - for $20, as these eBay scammers claim. |
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Bronze Member Username: MotleyPost Number: 22 Registered: Dec-03 | Before folks start busing me out for fighting on this board, I just had VERY MILD disagreements with two small points in Gadgit's last post. Overall, I agree with his points with seem to concur with mine. So, holster your Flames! |
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Unregistered guest | Stephen you and me want the same thing at the end of the day to put the shammers out of business It would'nt be so bad if they said "you will get a fuzzy watchable image with this kit" but they are selling it for something it's not. When I say build a DIY projector I dont mean get a plastic lens and some card board if you go to these links you will see a projector built by Prof who is now getting a bright image from his unit but it is all due to the high gain screen that is where the key is http://groups.msn.com/diyprojectiontv/updatedultimatetvprojector.msnw screen shots http://groups.msn.com/diyprojectiontv/screenshotsontheuhgscreen.msnw I would post pic's of mine but my digi cam just wont take good enough images. |
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