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Old 23rd February 2006, 04:45 PM   #11
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Join Date: Feb 2006
Location: Texas
I have done a bit of math, and i agree with what the previous said.

If you were to run a 2000 hour Commercial bulb for say... 5 hours a day, Which is about the whole class day except lunch/recess/ and so forth, then youll get about 80 weeks - 5 day a week 5 hours a day

I dont know about schools, but i assume that kids are only in school for about 30 a year, er 30 - 5 day weeks per year. Days of and the like kinda cut in. But this is the deal, if you only had to replace the bulb once every 2 years, then you would probably do better just buyying a new one every two years, which by that time might have longer bulb life, and more lumens.

But i still think DIY can work, with several stipulations. It is true that the parts are very fragile. But i think thats a lame excuse, seeing as it is not only possible, but easy to have an LCD framed into wood, and have it perfectly sturdy with no chance of breakage.

As for the theft, ..... If budget permits, you could do like all the universities and perminantly mount them to the ceilings, and thus keep the sweet spot.

And if you were making them all exaclty the same, you swhould be able to keep a spare, incase one thats hanging goes out, and simply change it out. They are fragile, but they arn't as fragile as you think.
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Old 23rd February 2006, 04:59 PM   #12
v1d9uy is offline v1d9uy  United States
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Join Date: Oct 2005
y couldnt you just use a older OHP with a lcd panel like sharp 1800 or so ... its easy to use easy to move .. durable cheap bulbs... i just got a dukane 641 ohp from college surplus for$5
with working bulb.. i got my sharp 1800 in like brand new condition for $120.. so im out $125 total !!! .. and it works fine....
a diy projector can work for you ..
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Old 23rd February 2006, 05:24 PM   #13
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Location: Motor City
A projection panel on an overhead might be the optimal solution here. They are generally considered outdated technology, but they're cheap and highly portable.
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Old 24th February 2006, 01:39 AM   #14
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Quote:
Originally posted by kb18951452
[B

If you were to run a 2000 hour Commercial bulb for say... 5 hours a day, Which is about the whole class day except lunch/recess/ and so forth, then youll get about 80 weeks - 5 day a week 5 hours a day
[/B]
True but the bulb dims so much that most of the time you will need to change it after around 1000-1400 hours. So you have to factor that in also.
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Old 24th February 2006, 03:44 AM   #15
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Join Date: Jul 2005
Location: Colorado
I totally disagree that DIY are so much more fragile than commercials. Like someone already said, you just have to mount parts correctly and securely. Yes a commercial projector is more stable but not that much more.

You can make a DIY adjustable enough for multiple throw lengths. That's not a problem. Just make an extended projection lens adjuster.

Upkeep. DIY have SLIGHTLY more upkeep than a commercial. That is to 1. wipe the lenses for dust and 2. change the bulb. You MIGHT have to dust once a month, if that and change the bulb once every 5 or 10 years. I haven't cleaned mine yet and I have several months on mine. Also, the bulbs last 5 to 10 times longer and are 10 to 20 times cheaper!

So you get 80 weeks out of a bulb (at best). So every 1.5 years you are paying $300 - $600 for a bulb (probably more than what you paid for your DIY projector). That's not including if ANYTHING else breaks on the commercial. So in a 10 year span, you pay $800 for the projector, $2000 - $4000 just for bulbs, plus the cost if anything else on the projector breaks. DIY: $500 for the projector and.... wait.... that's it! The bulb would last you 10 years! Ok, let's assume they are more fragile and EVERYTHING breaks (including the solid iron ballast). Let's say that happened 3 times. You are still WAY less than the commercial. The cost to repair a commercial projector is astronomical! You think the bulb costs a lot. Try the lens or the LCD (or DLP). There are no 5 minute fixes for a commercial either. It breaks, back to the manufacturer it goes for X amount of time (probably weeks).

Sorry, I had to get that off my chest. I do like the overhead projector (OHP) idea. Get a 800x600, 1024x768 LCD overhead panel. $50 - $100 for the LCD panel, $50 for the OHP (or you might have one already at the schools!). But I wanted to add that you could modify the overhead projector by replacing the OHP's lighting with a MH bulb and ballast. Bulb and ballast are around $100 new. This way, you get the bright white color of a metal halide (MH) bulb, the super long life (20,000 hours), and the super cheap replacement ($35 - $50). The only thing you MIGHT need to add is an extra fan, maybe another $10 - $15.

So you are talking $250 for a complete setup (minus computer) for a portable, bright, and safe setup. Good idea v1d9uy.
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Old 24th February 2006, 12:02 PM   #16
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The LCD's are going to be a trick to get.

I have some ideas, if your s school.

First off, The OHP conversion is going to be pretty dang easy, but thats going to be a bit more fragile than a boxed up one, so you might think about converting OHPs and then boxing them in. But everyone is right.

Commercials are going to cost a bit.

So if your going to do DIY PJ for a school what kind of things is the design going to need?

This seems like the next logical discussion.

LCDs, I think a school could probably get a computer store, and independant computer repair guys, and those little shops that do computer sales, to donate "Broken" LCDs to your project, for a full value tax writeoff. Meaning, That if you go and find usua\bly "broken" lcds, you should be able to get them free, if youll give the guys a working LCD writeoff reciept. Because for all intents and purposes you would be paying full price for a new one.

How do you know the LCD is usuable, if its broken? Well, first off, its just going to be dark, or black, when its tried in normal use. Or there is going to be darkness on a large portion of the screen, like the bottom half, or top half.

Why do these work? Because only the backlight is gone, and you can tell that this is the only problem by placing a flashlight flat against the LCD panel, on, and looking for collor around the rig of the flashlight, whrere the light is bouncing back.

A little dissasembly is required, and with a little luck you should be able to get your hands on, atleast initially, a few LCDs for nearly nothing.

Also, Things need to be very sturdy, like was also said. So youll probably have to get a good setup, then when you build the next one, build it like its gonna get bumped around. everything very secure. And a lightproof side door to reach in and clean the bulbs, and such would be a good idea also.

What else would someone need for a School Projector?
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