DIY Projection

M

mtxblau

Mid Boss
Ah, google is quite a friend.

Anyway, I came across these plans to build a DIY Projector with nothing more than a fresnal lens and a cardboard box. Do these things actually work?

http://bigscreentv.20m.com/photo.html

I've already seen the projectors with the LCDs and what not (re: way out of my price range).

If this thing even remotely does what it claims, it sure as hell worth the money, no? I'd be using an Amiga monitor with a Panasonic AG-1960 ProLine (hence, screen sharpness is not an issue).
 
AFAIK they do work, but I'd imagine that they have poor convergence (distortions at the corners are probably magnified) and brightness (you're taking a fixed amount of light emitted from the tube and spreading it over a much larger area). Whether or not it's usable probably depends on what you're viewing on it and how dark you can make the room.

edit: OTOH, if I can find a decent source for the lenses I may have to give it a shot just for the chance of throwing Ikaruga on a wall :drool:
 
just tried it (minus the box) grabbed one of those magnifying sheets and held it out a distance from my TV with a white piece of paper a few inches from the lens untill i saw a semi-clear picture... image was upside down but was being projected, image was small and i don't know exactly how this would expand to a large image very well, but now i've got to try it :lol: ....just need for find an old TV in the trash that i can screw around with and turn upside down.

PS. was holding the stuff in this order:

white paper --few inches-- magnifying sheet -- few feet -- 27" TV screen.

image size was very clear in the center, distored out towards the edges.
 
Heh, I've done this before using an amiga monitor. I could never get the clarity to be very good, and the room has to be very dark to get much of an image at all, but for being a cheap plastic lens and all it works okay. It does work OK if you use two boxes, preferably painted black on the inside. Also, not sure on this one, but I think if you use two lenses you can get the image right side up without flipping your monitor. I definitely don't think it would work for Ikaruga or anything like that- you wouldn't be able to make out the bullets well enough.
 
How far away from the wall were you when you tried doing it? I plan to do it per spec, and paint it all black and such.

Does it make a difference in clarity that there is a circular hole limiting the output? I mean, is it physically noticeable? (given the physics of the lens used, I imagine there is no difference, but then again, who knows?)

It seems most DIY projectors are now using the transparent LCDs that they use on the old fashion projectors. The output is fantastic, from what I can tell...

http://users.pandora.be/emmanuel.geeraert1/diyvp/

For Ikaruga, I can only imagine the possibilities.

As for the lens recommended in the cheap DIY, I found this:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...tegory=298&rd=1

I'm going to give it a shot, and see how it all works out.
 
I bought 4, I'm gonna try it as a single and as a double, got a couple friends interested in trying it also (hence buying 4) we figure if worse come to worse and it doesn't work with snot (very likely) we'll just use them in conjunction with my old headlights and an old car battery to create a box of blinding lol.
 
How far away from the wall were you when you tried doing it? I plan to do it per spec, and paint it all black and such.

Does it make a difference in clarity that there is a circular hole limiting the output? I mean, is it physically noticeable? (given the physics of the lens used, I imagine there is no difference, but then again, who knows?)
Click to expand...

Hmm, I probably had the monitor about 10-12 feet away from the wall, not sure. That prooduced an image that was maybe 6 or 7 feet wide. Not really sure, I did this back in 1995 or so. As for the circular hole, I used a square lens and cut a square hole, so I dunno.
 
Originally posted by MTXBlau@Dec 3, 2003 @ 01:13 AM

It seems most DIY projectors are now using the transparent LCDs that they use on the old fashion projectors. The output is fantastic, from what I can tell...

http://users.pandora.be/emmanuel.geeraert1/diyvp/

For Ikaruga, I can only imagine the possibilities.
Click to expand...

yeah but the guy spent hours on hours of time for that thing and it ended up costing him $800 anyway...why not just go buy a real one for $1000, have perfect picture quality and a fraction of the size.

And just found another problem with the cheap one (the fresnel lens one...)

THE TEXT IS BACKWARDS, even if you flip the TV upside down so that the image is the right side up, it's still a mirrored image, so text is backwards and if you played games etc... you would be going in the wrong directions... DAMN IT
 
what if you used 2 lenses? The more I look at it, the more I think I'm going to go the overhead projector/lcd panel route, that seems to be the cheapest way to get good results. I'm going to use a 3m 9800 overhead I think, it seems to be very bright and has a triplet lense to help with distortion at the corners, and the bulbs aren't too $$$. Just gotta figure out what panel to go with.
 
I think I figured out what I wanna get in teh way of an overhead, it's a 3m 9800, it's a 6000 lumin overhead with a triplet lense. I'm bidding on ebay on a couple of possibly DOA lcd panels. If I win both, and both work, I'd be willing to sell one most likely for about what I paid. I may go take a look at office depot though, cause a 3m 9800 is like $100 on ebay before shipping, and most decent ones are still $100 even after shipping, so if I can get a decent one at office depot for $100, it'll save time, and possibly money.
 
i just had a friend bid on an LCD panel for me...won it for $15.50.....let's see what the shipping ends up costing....

Only says the unit powers on...will be interesting to see if it actually works :blush:
 
if you get it up and running keep us posted. I'd like to see some pics. If I wint hese auctions, and if these lcd's work, we're probably going to actually just go for it on the building with lenses and not using an overhead projector.
 
Waaaaaait a minute.

I have a laptop screen that I'm not doing anything with. Think that can be modified for usage with this little set up? Instead of the TV, I could use that LCD screen (gutted, minus backlight) with a halogen lamp and a fresnel lens?

It's 800x600, 256 colors, 11.3". I also have an 800x600 10.something", though 16-bit. (they're from the same laptop)

In either case, I need to get me those lenses.
 
from what I've read, those should work, however you need to keep them intact inside, and extend cables, and it just sounds like more work than it's worth to me (I have 2 laptops just laying around too). Check out diylabs.org and hommie.net between those 2 you can get quite a few ideas on how this stuff works, and links to countless people who have done this stuff.
 
HI :) ,

Great post,

I have tryed many methods of projection.Currently use a Sanyo lcd projector which i once shon on the neighbours house over the road.The image was huge and i put Sonic the hedgehog on the megadrive through it and Sonic himself was as big as the guys patio windows.

The ohp system looks good but the only downside is the bulb life span.I guess that if yuo restrict usage you could make them last for a few months,Also remember they have fans inside which may cause a noise.

The lens method had intresting results,You have to be very exact in construction and block out all light.The downside is that normal tv sets dont kick out that much brightness to begin with,So fine adjustments are critical.Saying this though the screen i managed to get was really big in a smallish room.

By afr one of the best methods me and a freind tryed was to buy one of the old Philips back projection televisions.We took the screen off from the front and hey presto--3 nice big tubes/lenses to shine onto a white surface.the quality was very good indeed and produced a 120 inch screen.The Philips sets can be had for very little these days,Just pop the scren of and you have a front projection system.Maybe this works for all sets i dont know.

Another tweek i use if you are using an lcd projector is to use a large mirror.

This gives you the oppurtunity to reflect an image in a smaller room to twice its size.Mario 64 and Radiant silver gun looked menacing on a whopping scree. :devil

Hope this helps,

Ian.
 
Yeah, I'm going the lcd panel and lighting from the back route. I've looked at a few alternative light sources to what they are suggesting, and I think I've figured out what I'm gonna do, I'll keep you posted as I actually do this, and what my results are.
 
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