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Author	Topic
cory5412 68KMLA Comrade-in-Arms USA 4679 Posts	Posted - 07 Mar 2003 : 23:56:42 I've always wanted one of those great Computer/TV Projector things... is there a reason why the ruddy things are SO expensive and last for so short? I'd think that it's just like an LCD but small and with a big light bulb and lenses in it right? any ideas on how to get one cheap? anyone have one? any insight on projectors that sit on overhead projectors? think I should dissasemble the cheapest LCD I can find and attempt to get an overhead projector to make something like this on my own? in fact... I think that that would be fun! Official 68k videographer Official MLA TourGuide
Trash80toG-4 NIGHT STALKER USA 2899 Posts	Posted - 08 Mar 2003 : 02:10:27 quote: any insight on projectors that sit on overhead projectors? think I should dissasemble the cheapest LCD I can find and attempt to get an overhead projector to make something like this on my own? They're not TOO expensive on eBay sometimes, but making your own wouldn't be a very good idea, projection bulbs put out a LOT of heat, so the LCD needs to be as translucent as possible and heat resistant too. Less of either would be bad, but less of both characteristics would be a surefire formula for disaster. The cooling fans on the panels would be key components too. It would be easy to build a projector using fresnel lens condensors and a TV projection lens. jt . Trash Hauler: call sign: eight-ball C.O. AC-130H SpecOps 68kMLAAF edit: found some info: http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=006hui Edited by - Trash80toG-4 on 08 Mar 2003 03:30:25
Flash Full Member Australia 637 Posts	Posted - 08 Mar 2003 : 06:42:56 Fresnel? No. Condensor, yes. Unless of course you want an unfocusable image When you say 'TV projection lens' do you mean those lenticular (sp?) screens that sit in front of the telly, enlarging the image? Re: the LCD panels that sit on an overhead.... they're absolute crap. Don't buy one unless it is really cheap. And another piece of advice.... don't buy a projector uless you've checked out the price (and availability) of spare lamps - they can be bloody expensive! cheers Flash! (throwing his 2 cents in again ) - - - - - - - - - - - - - A little knowledge is a dangerous thing, but it sure beats a blank stare for starting a conversation. 68k ParaMedic
Trash80toG-4 NIGHT STALKER USA 2899 Posts	Posted - 08 Mar 2003 : 07:19:06 quote: Fresnel? No. Condensor, yes. Unless of course you want an unfocusable image When you say 'TV projection lens' do you mean those lenticular (sp?) screens that sit in front of the telly, enlarging the image? The fresnel lens IS what you use for the condensor, that's what the clear platen on an overhead projector is! The projection lenses for TV are long focal length , very fast compound lenses, but you need to find one that is color corrected. The MacAquaKlugeCamJector I worked up as a (somewhat over the top ) hack proposal gives a rough idea of the basic layout. That's VERY good advice about the price of replacement lamps, the suggestions in the link above sounded interesting. jt . Trash Hauler: call sign: eight-ball C.O. AC-130H SpecOps 68kMLAAF Edited by - Trash80toG-4 on 08 Mar 2003 07:27:38
cory5412 68KMLA Comrade-in-Arms USA 4679 Posts	Posted - 08 Mar 2003 : 07:57:17 well for the most part, I was under the impression that if I got an overhead projector panel instead of a more expensive shorter lasting regular electronic projector, I'd be happier because I'd have a less expensive unit that needn't have lightbulb changs.... are regular overhead light bulbs expensive? Official 68k videographer Official MLA TourGuide
G4from128k Full Member USA 873 Posts	Posted - 08 Mar 2003 : 08:28:56 Replacement lamps for overhead projectors will run $10-$30 each and usually have a lifespan of about 25 to 90 hours. Personally, I like jt's design that uses the screen off of a Powerbook and the lighting/optical system from a classroom overhead projector. The image won't be very bright -- monochrome LCD panels absorb more than 50% of the light, even when "clear" and most color panels absorb more than 90% of the light when "clear". That is why laptop screens look so black when the backlight is off. All those polarizing filters and color stripe filters in the LCD panels attenuate light severely. This also means that most of the light from the lamp is absorbed by the panel and converted to heat. I would scavenge two of those long squirrel-cage fans found in old photocopiers, mount one to cool the under surface of the panel, one to cool the top surface of the panel. G4From128k by Day: Mild-Mannered Engineer and Trapeze(tm) Artist by Night: Colonel of Truth, Justice, and the Macintosh Way Reserve Officer in 68kMLA Cantankerous Coot Contingent
Trash80toG-4 NIGHT STALKER USA 2899 Posts	Posted - 08 Mar 2003 : 08:54:53 quote: Replacement lamps for overhead projectors will run $10-$30 each and usually have a lifespan of about 25 to 90 hours. That's not quite as expensive as I'd thought,I have parts to use lamps from the opaque projector I used to use for enlarging artwork in the pre-computer era! I always wanted to build a horizontal copy camera type projector using overhead projection components, that's why the fish-cam hack was fun to play around with. quote: Personally, I like jt's design that uses the screen off of a Powerbook and the lighting/optical system from a classroom overhead projector. The image won't be very bright -- monochrome LCD panels absorb more than 50% of the light, even when "clear" and most color panels absorb more than 90% of the light when "clear". That is why laptop screens look so black when the backlight is off. All those polarizing filters and color stripe filters in the LCD panels attenuate light severely. This also means that most of the light from the lamp is absorbed by the panel and converted to heat. That's why I was using an for an overhead projecter LCD panel. I was very surprised to find anyone talking seriously about useng standard LCDs for projection systems because of the heat buildup from less than optimal translucency/transparency. Maybe I'll still score an LCD panel, playing games projected on the ceiling slouched back on a couch would be wicked. wonders what the grlf would make of a fishcam/coffee table/ceiling TV projection system? sighs jt ™. Trash Hauler: call sign: eight-ball C.O. AC-130H SpecOps 68kMLAAF
Gothikon Full Member Australia 537 Posts	Posted - 08 Mar 2003 : 14:44:06 I didn't read all of JT's suggestion but I would also like an overhea projector. There are a number of PC mods sites that have links to DIY computer projectors. Some you build yourself and require minimal DIY skills, eg cut and glue 6 panels, drill some holes. Other simply use one of those VGA LCD panels that are actually intended for over head projectors, i think I have seen the on eBay for around 50-60 USD, and an overhead projector can often be found at school/uni clearouts/garage sales or again on eBay although you'll pay a bit more. Most of the projects were completed for under a 100 USD and had pretty good results. I'll check my links again because one explained how the OHP bulbs were graded and what was a good price/bulb life ratio. Oh and if you do get an OHP look for one that can hold two bulbs as they often let you swap them on the fly, handy if one blows halfway through a DVD! I suggest you use google -------- LC 2, LC 3, Q605, Perf 638, Colour Classic (160 603e) 6100, 7200, PTP 225 (Quad 604), PM 9600, G4 Cube
cory5412 68KMLA Comrade-in-Arms USA 4679 Posts	Posted - 08 Mar 2003 : 20:15:03 hehehe... I have ALWAYS wanted an overhead projector of my own anyway, the bulbs last ALOT longer, and of the panels designed for this use, they are thicker and have better ventilations, so that shouldn't be too much of a problem... next issue: finding one for less than $100.... for my own purposes I would like one that can do color, any resolution really works pretty good if it's at least in color... but the higher the resolution, the more I'll want to use it... I was thinking of having a Presentation Cart with the 7300 running OS 8.5 and MS Office 98 and some external speakers for giving presentations and whatnot... this way I can give effective presentations with audio effects and color graphics, or even just use the screen for iTunes effects.... I always am debating on weather I should include a monitor on the cart and usually I come up with "no" because "it has the big screen already" I think that if I leave the 7300 on the desk and put the 6500 on the cart, I can run PPT on it in MacOS 8.1 and take advantage of that built in subwoofer? Official 68k videographer Official MLA TourGuide
Gothikon Full Member Australia 537 Posts	Posted - 08 Mar 2003 : 21:02:21 You'll probably find 800*600 is the best price/performance ratio. Much higher and they will start getting really expensive. Also the extra detail will be less noticeable. Did you google for any diy tutorials? Like I said some of them were really good and told you what you should expect to pay and listed some sources. -------- LC 2, LC 3, Q605, Perf 638, Colour Classic (160 603e) 6100, 7200, PTP 225 (Quad 604), PM 9600, G4 Cube
Trash80toG-4 NIGHT STALKER USA 2899 Posts	Posted - 08 Mar 2003 : 21:15:03 quote: You'll probably find 800*600 is the best price/performance ratio. Much higher and they will start getting really expensive. Also the extra detail will be less noticeable. Did you google for any diy tutorials? Like I said some of them were really good and told you what you should expect to pay and listed some sources. The 640x480 Panels seem to be very reasonable and that's the limit for resolution for the 6xx/6xxx Video Subsystem. By overhead projector, I'm actually talking about using the ceiling as the screen! jt ™. Trash Hauler: call sign: eight-ball C.O. AC-130H SpecOps 68kMLAAF
cory5412 68KMLA Comrade-in-Arms USA 4679 Posts	Posted - 08 Mar 2003 : 22:09:09 well ALL of the overhead panels are cheap, there's no any other way about it lately... all are under $200 even some of the great like... InFocus 1024 by 768 ones.... these things truly are considered obsolete.... I like 800 by 600 or 1024 by 768 though, because it allows me to do more than simple PowerPoint presentations easily. I am using this screen at 1280 by 854 and would never be able to use OSX at anything less than 1024 by 768... this is BTW going to be an OS8 or 9 based system.... I think that whatever the MultiScan 15 monitor can do, is good for the PresCart Official 68k videographer Official MLA TourGuide
catsdorule Senior Member Canada 1627 Posts	Posted - 08 Mar 2003 : 22:10:12 I want a projector for viewing my games full screen . -danny You! What PLANET is this! -- McCoy, "The City on the Edge of Forever", stardate 3134.0 ------- 68k Macintosh Liberation Army 68k Macs Liberated: 3
cory5412 68KMLA Comrade-in-Arms USA 4679 Posts	Posted - 08 Mar 2003 : 22:59:09 well I think that watching movies and browsing internet like that would be COOL...... PowerPoint (and Keynote) are great and all... but nothing compares to MLA on a 600" Drive in theater size display (or however that works out) here in the desert, there's noone to read your posts Official 68k videographer Official MLA TourGuide
Trash80toG-4 NIGHT STALKER USA 2899 Posts	Posted - 08 Mar 2003 : 23:12:39 quote: ... but nothing compares to MLA on a 600" Drive in theater size display (or however that works out) I just thought of something better than the MLA to project on the ceiling . . . . . . besides the FishCam video! jt ™. Trash Hauler: call sign: eight-ball C.O. AC-130H SpecOps 68kMLAAF
cory5412 68KMLA Comrade-in-Arms USA 4679 Posts	Posted - 08 Mar 2003 : 23:26:24 do I EVEN want to know what that is???? ooOOOoo .ME projects piccies of QuadraGuts on his ceiling..... Official 68k videographer Official MLA TourGuide
maclover5 LC Doctor/Hot Rodder Australia 5830 Posts	Posted - 09 Mar 2003 : 21:49:18 quote: I just thought of something better than the MLA to project on the ceiling . . . . . . besides the FishCam video! pr0n? -------------------------- Give your dreams a chance.™ - Apple in the mid '90s Warrior maclover5 68k Macintosh Liberation Army Number of 68ks Liberated: 7
Trash80toG-4 NIGHT STALKER USA 2899 Posts	Posted - 09 Mar 2003 : 22:46:22 quote: quote: I just thought of something better than the MLA to project on the ceiling . . . . . . besides the FishCam video! pr0n? :rolleyes: Flight Sim Projections! jt ™. Trash Hauler: call sign: eight-ball C.O. AC-130H SpecOps 68kMLAAF
catsdorule Senior Member Canada 1627 Posts	Posted - 09 Mar 2003 : 22:55:47 ooooo see those planes explode o the wall!. -danny You! What PLANET is this! -- McCoy, "The City on the Edge of Forever", stardate 3134.0 ------- 68k Macintosh Liberation Army 68k Macs Liberated: 3
Trash80toG-4 NIGHT STALKER USA 2899 Posts	Posted - 09 Mar 2003 : 23:04:28 quote: ooooo see those planes explode o the wall!. Heads Up Display! jt ™. Trash Hauler: call sign: eight-ball C.O. AC-130H SpecOps 68kMLAAF
catsdorule Senior Member Canada 1627 Posts	Posted - 09 Mar 2003 : 23:27:05 LOL indeed. -danny You! What PLANET is this! -- McCoy, "The City on the Edge of Forever", stardate 3134.0 ------- 68k Macintosh Liberation Army 68k Macs Liberated: 3
cory5412 68KMLA Comrade-in-Arms USA 4679 Posts	Posted - 10 Mar 2003 : 06:21:53 that would fall under danny's "games" category of uses for projection??? Overhead bulbs last pretty long I'd say... at school it's usuall a few months before any need to be replaced, and these things usually run all day save for planning periods and lunches..... Official 68k videographer Official MLA TourGuide
Gothikon Full Member Australia 537 Posts	Posted - 11 Mar 2003 : 00:01:12 quote: I want a projector for viewing my games full screen . So you're going to project on to your monitor I'd be thinking full wall at the least! Reminds me of the time we hooked a friends laptop up to one of the projectors at uni while the theatre was empty, can you say Q3 on a screen about 25 feet wide? it's just a shame we didn't have speakers to match -------- LC 2, LC 3, Q605, Perf 638, Colour Classic (160 603e) 6100, 7200, PTP 225 (Quad 604), PM 9600, G4 Cube
cory5412 68KMLA Comrade-in-Arms USA 4679 Posts	Posted - 11 Mar 2003 : 18:26:44 InFocus has this beta test thing... I want to join it but I need to answer: Describe how you use InFocus projectors in your every day life: the dillema: the science teacher here has this loaner cart from library, and that has a DUKANE projector on it, and the one that the science teacher in WA had was like... Toshiba or some other one... (really compact though) and I don't have one... so I need to get an older one that's an overhead projector type one.... I want one off of eBay though.... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3405622924&category=25321 an InFocus is it not? from the name, it's a color InFocus, and it works! cheap too... whaddyathink? Official 68k videographer Official MLA TourGuide
cory5412 68KMLA Comrade-in-Arms USA 4679 Posts	Posted - 17 Mar 2003 : 20:25:02 it's really fun... MLA and all on a 27" TV... I guess that a TV will suffice until I can afford a new projector and a lamp or two... or one of the projector panels... Official 68k videographer Official MLA TourGuide

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