Call for DIY Projector advice - for tonight feb 22 - diyAudio
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Old 22nd February 2006, 03:51 PM   #1
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Default Call for DIY Projector advice - for tonight feb 22

Greetings all,

I'm part of a not-profit drive to explore the possibility of putting wikitextbooks into classrooms where textbooks are too expensive to keep buying them over and over again(and for a gaggle of other pedagogical reasons). As you might imagine, one of the biggest issues is delivery of the textbook in the classroom. I have haunted these forums in the vague desire of building my own projector over the last year, but don't really know what i'm talking about. In spite of this, i have suggested that a DIY projector solution might work based on the lower cost of initial investment, and bulb replacement.

I'm looking for a couple of things.

First - the answer to some questions.

1. Is anyone manufacturing DIY projectors? (please don't tell me this is an oxymoron, i know, my life is full of them)
2. Is it possible, if so how?
3. Is anyone using DIY projector solutions for education?
4. Could it be done? What would we need?
5. Is it possible (bear with me) to get a group of student entrepreneurs to build these for schools?

Second - I would love to have someone come on the show live (we do a live webcast at educationbridges.org, tonight 8pm EST) to talk, or at least hang out in the text chat room to answer some questions?

cheers,

dave.
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Old 22nd February 2006, 04:27 PM   #2
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This is just my opinion, but I believe for that type of application a commercial projector would be vastly superior. DIY projectors simply don't put out as much light. For a home theater viewing experience that's an acceptable limitation. The solution is to only allow a limited amount of ambient light into the room and to direct it away from the screen. But for a classroom environment that's not practical.

Further, while a DIY projector can be quite reliable and inexpensive to operate, they just aren't as robust by nature. And they're bulky. I know the cost would be higher but I would go with an inexpensive commercial unit because you need these PJs to work on a daily basis, many hours a day, and there will be light in the room. In fact, many are so bright that the room's lights wouldn't have to be dimmed much at all and the students would easily be able to read what's on the screen.

I look at DIY projectors as more of a hobby than as a way to save money. I'm building one more for the satisfaction and "wow" factor than anything else.
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Old 22nd February 2006, 04:54 PM   #3
cowanrg is offline cowanrg  United States
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agreed. you can get a used projector for a few hundred $ if you look around.

a DIY solution will be just as much, and wont be nearly as friendly. its going to be much larger, the quality will be more suited for a dark room, and lets face it, its DIY, things could break.

go and find some cheap commercial projectors.
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Old 22nd February 2006, 07:18 PM   #4
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Default mmm...

Thanks for the opinions... I'm glad i asked. The difference in the money we're talking about though... particularly in the bulb replacement cost is fairly significant. mmm... I may have to rethink this. Anyone else want to give me a third opinion and contradict what seems to be good sound advice from these other fine posters?

dave.

ps. I still think i'll build one.
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Old 22nd February 2006, 08:00 PM   #5
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This is my thinking.

I dont know about you guys, but last time Mrs. Abernathy was teaching me math and going problems on the olf OHP (over head projector) it wasnt the smallest of things either.

Everyone knows that when you DIY you cut corners, because you KNOW no one is going to be touching it, and that everyone who would touch/move it is going to know every little fluke of its design, and works accordingly. Thus, if you need to cut corners, you might make your home one stationary, having to be set in exactly the same place every time, or perminant, like on the ceiling.

So this is what i think. I think that you could work pretty well by two things. One thing is, see if you can get help making a smalled more compact design. (in reality it can be just as big as Mrs. Abernathy's projector ontop of the rolling cart, tha gives you a size deminsion of about 3-4 foot high, or not a little higher. )

Essentially you could probably modify a projector cart by adding wals to the thing, and putting all the components inside the frame, seal it up, and walaa, you have digital projector the same size as the old projectors. (infact you might even trick students by leaving the shells of the old OHP ontop and shooting the beal right thru the normal aperture, and mirrors that are in an OHP.

I hope these help.

I have one other thing. When we are at home using out projectors we want the thing as big as possible. When an OHP is used in the classroom, these kids are young, with good eyes, and not allot of complaints with tech. so if you make the image on the wall smaller, thus the image brighter, and maybe dim the lights in the front of the room. I think it would work. The other solution would be a bit more complicated in one area, and that is:

You could perminantly mount the projectors to the ceiling, and run VGA extenders through the ceilings (the easy part) and down the walls (outside the wall is easy, inside is harder) and then simply plug it to a computer, or VCR (by way of a converter) and so forth.

Doesn't seem like a hard decision.

And i know what you talking about with the cost. Yea commercials are cheap, but not in the long run. If these DIY are done right, with the corners not cut, then you should be able to get decent, non ghetto looking projectors for a good chunk of change, and still save because the bulbs last atleast 5 times longer than other ones and dont cost but a tenth as much as commercial bulb replacements.

Please excuse all my misspelling.
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Old 22nd February 2006, 08:03 PM   #6
cbm5 is offline cbm5  United States
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Going back to your first question: to my knowledge, no one is manufacturing and selling a complete DIY-style projector. DIYProjectorCompany comes close with their MDF cabinet kits, but it still requires work on the part of the builder to strip the LCD, figure out how to mount it, arrange proper cooling, etc.

However there's definitely enough experience in these forums to start a turn-key projector company. The issues with reliability and brightness will go away to some degree with a combination of experience and developing a consistent, optimized design.

The only problem is that a finished projector would cost, say, $400 to $500. Maybe in large volume that could be knocked down. But commercial projectors are fast approaching that price level and with better results, the only remaining obstacle being the cost of lamp replacement. Many buyers are reducing that cost with a warranty plan, or realizing that by the time the bulb burns out, they could buy an entire better projector for nearly the same price. And to some people $200-$400 a year is acceptable for bigscreen movies and TV combined with portability.

The main attraction of a DIY projector right now is the DIY part. I enjoy working on my projector, tweaking the lamp and optics and seeing the picture improve a little more.
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Old 22nd February 2006, 09:01 PM   #7
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Sure love to give contradicting info. Actually, these guys are correct that the light level that a typical DIY projector puts out is not as much as a commercial projector.

BUT! There are ways around this. Firstly, the screen you shine your projector on can make a HUGE difference in picture brightness and quality. There are threads (on www.avsforum.com) where people have mixed household paints together to be painted on a screen (or board) to enhance the picture. Some are tuned more at blocking ambient light. Some are tuned to bring out contrast. Some are tuned for more vibrant colors.. You get the idea. One thread that was a good one there is:

http://www.avsforum.com/avs-vb/showthread.php?t=598670

Also, it might be possible to block off a section of a room so that when the kids want to use wikipedia (or the projector in general) they go into the "dark" room and use the computer there. If you can control the lighting to part of the classroom that would work too. If you are talking about mass presentations for the entire classroom, you'd have to simply close all the shades and turn out the lights. There are ways around the light problem.

DIY projectors are bulky. I don't think they really have that much more maintanence than commerical projectors. The only mechanical parts are fans and the only other parts that are electrical are the LCD and bulb.

I totally agree with you that DIY are cheaper. Replacing the whole projector is probably cheaper than replacing ANY part in a commercial, especially the bulb.

If you find that you can get the appropriate conditions (ie the lighting) for a DIY, I'd be willing to help you out.
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Old 23rd February 2006, 01:58 PM   #8
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Default I love the contradiction as well!

Thanks muchly for the detailed responses everyone,

It's a hard road we're trying to run here. The school districts that we are trying to get into don't have the infrastructure needed to get the technology to bring their kids up to the level of some of the richer districts. Initial cost, which can often be covered in outside funding, is far easier to find than upkeep costs. (see me babbling about bulbs again) The 400-500 dollar price tag, which is just a fraction higher than what i've suggested to people, would be do-able. And the right blinds could be included in that initial cost. The other issue with video projectors is that they get stolen all the time. I was talking to a guy from Ann Arbor the other day, and he said that they've lost 147 projectors in 18 months in their district. Build 'em big and bulky i say.

I'm very concerned about upkeep... and durability. How would it respond to being on wheels for instance.

What I'm sensing here is - it can be done, if it's done right. And right will take some time to work out. But if I was able to get a grant to explore the idea, and get some good people together, a prototype that might work could be built... Of course, that would mean that alot of the parts that you guys are getting might become more expensive. or cheaper. capitalism is a weird thing.

but think of the children!

cheers. and thanks again.
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Old 23rd February 2006, 02:21 PM   #9
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Here is what i think,

I think they can be made very durable. If you talking about working with grant money, you just need to put a few more dollars into all of them except the first, and depending on how you do it, that one might cost more or less.

The truth is, that these things can bery very sensative, but anyone here knows that they are sensative because they are always tweaking they're projectors, and so things aren't "nailed-down". I KNOW that with a bit of work on your first design, you can get the perfect situation making e erything stationarily designed (meaning that if its on wheels, that you are going to be wheeling it to about exactly the same place from the wall or screen every time you use it.)

You can make this work, and its not going to be a big thing. No these things arnt made "Commercially" but there are several people here that will make you one if you buy the parts, plus a little extra. Cruser, and Ace3000 are two that i can think of at the moment.

No commercial production,. but there is Cottage production.
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Old 23rd February 2006, 04:27 PM   #10
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Default Re: I love the contradiction as well!

Quote:
Originally posted by coarsesalt
I'm very concerned about upkeep... and durability. How would it respond to being on wheels for instance.

Well, let me elaborate why commercial is the way to go.

You just hit on two huge issues - upkeep and durability. A DIY projector is going to be less durable no matter how well it is built. The reason is because it involves a fragile LCD that is far larger than any found in a commercial projector (and most commercial PJ's use DLP now anyway). You also have delicate FFCs connected to the LCD which can tear from the slightest bending or vibration.

On upkeep, commercial units only require bulb changes. And bulb life has gotten much better lately, most units on the market now offer 2-3k hours or more (I've seen up to 5k hours on projectors that cost less than $1,000). A DIY will be prone to collecting dust inside so they need to be cleaned periodically. The bulbs last longer and are cheaper, but should anything else go wrong there are no five minute fixes. As I said earlier, commercial units are just more robust by nature. They have many, many hours of engineering put into them making them that way.

And you mention wheels. Possibly the biggest advantage commercial projectors have for an application like this is their focus adjustments. Typically they can be set anywhere from a few feet to 20+ feet from the screen and you can get a focused picture in seconds. Building focus adjustments, or even keystone adjustments, into a DIY is no small task. If you want something that can be rolled or carried into a room and set up in a minute or two then you're talking commercial. DIY projectors are designed for a set throw distance resulting in a set screen size, and thus there is a "sweet spot" they'll need to be placed at. This makes portability an issue, and it's why many DIY users affix their projector to something (typically the ceiling).

Finally, about cost. Outside of the replacement bulbs there is going to be next to no cost difference. It's not uncommon to see commercial units on sale in the 500 to 600 range. If you buy in bulk you should get a decent discount too, especially considering it's for kids! Building several DIY units just can't be done cheaper than that. Assuming you source new LCD screens and controllers (vs. taking apart monitors, which has a risk of breaking them) that alone will eat up at least half of your budget. Then you need the ballasts, bulbs, fresnels, enclosures, etc. It's going to take a lot of time and effort and it won't save any money - it may even cost more. You might gain some resolution - low end commercial units are still 800x600, while a DIY based on a 15" panel will be 1024x768. But any resolution gains are offset by the lower light output.

At the end of the day I just don't see where it's worth it to try DIY here. Too much risk and effort, so little to gain. Besides, when the commercial units need new bulbs they can probably be replaced cheaper with whole new units as someone else said.

As a side note - I don't think DIY projectors would be any less prone to theft. My experience is that most theft like this is done from the inside, sadly. It's teachers and other staff making them disappear, and the bulk of a DIY unfortunately won't thwart that.
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