DIY Video Projector

[tomithy83]

i dont understand color temp what do the #s stand for?

[tech head]

tomithy83

to rehash.

color temp is equal to the temprature of light being produced by a star in degrees kelvin. the lower the # the redder the light. Normal light from our sun is between 4000k and 6000k. any hotter and the light takes on a blue color.

hope that clears it up.

[oftheend]

Darth Willis:

So your point is that you want someone to give you measured drawings and part lists (like PBS DIY woodshop shows) and proof of the output before you will even try. I am not trying to equal or surpass a 2000+ Xga lcd projector, or a CRT projector. I just want something to watch a movie on, and enjoy it. Who knows, maybe when I have more money I'll trow it out and get a CRT projector. But any way, Here is my setup right now.

Reflector >> 175 W MV >> Fresnal >> LCD >> DCV lens >> DCX Lens

Below is the list of parts I have bought for this project, whether or not i have used them:

3 fresnals @ 5.00
Delta HD 10 (?) Lens @ 10.00 + 18 shipping
Proxima ovation 810 640*480 panel @ 45.00
Jam it SVHS to VGA scaler @ 35.00
175 watt MV lamp @ 29.99
500 watt halogen worklight @ 9.00

So at the moment, my setup is ony 640*480, but replace the panel and i could have 1024*768. Right now the image is only watchable in complete dark, and it has a distinct green cast to it. Both of these problems will be solved when my new 250 Watt MH fixture arrives, it is in transit. ($64 including shipping)

If i had a good digital camera, i would show some pictures of the image produced, but all i have laying around is a Jam Cam 3.0, which is near useless in the dark.

With the MH the colors will render correctly, and the image will be much brighter. Probably will have to be watched in low ambient light anyway, but I really dont want to pay the electrical cost of a higher wattage setup. Once I add polarizers and a decent screen(my wall is medium grey), the image will be great for movies.

[tomithy83]

thanks tech head so i want 5000k right or at least close? where does halogen bulbs place?

[Undream]

Halogens are typically in the 3000's. Qaurtz Halogen can be a higher temp, but, they usually output less lumens per watt I think. IMO, halogen just isnt efficient enough. they create a helluva lot of heat too, and, that can be annoying to manage.

[tech head]

tomithy83

At the right voltage a halogen bulb could be the right temp, but the bulbs get VERY hot. In my humble opinion I think that the replacement bulb from an existing projector or ohp would be the best option. However, the light that you choose is mostly dependant on the size and type of lcd you use. (i.e. the larger the lcd the brighter the light needs to be and also the optics must be larger.)
The design that I am working on uses a ohp replacement bulb/balast, a 2.5" lcd with composit in at 320X240, and a 35mm zoom lens from a camera.
This is untried at present but the light path traces work on paper.

[tomithy83]

the thing is though i dont have alot of initial money i dont want to spent $40 on a light then find out it dont work anyway i can get a halogen 10,000 lumens for $10 and i have plenty of glass and fans for cooling

[tech head]

tomithy83

If all you want to do is watch t.v. or dvd on it you could use this:
http://www.globalsources.com/General...=3000000149695
one of your halogen lights, and a zoom lens from a 35mm camera.
I really think it would work if you can keep the temp down.

[Darth Willis]

No, I am not looking for PBS style instructions on how to do it. I'm a smart enough guy that I can do a project like this without anyone holding my hand. I just wanted proof of concept. The proof of concept that I've seen so far from over a year's worth of message thread has been an image that looks like it's come out of a 30 year old ViewMaster Projector. I don't find that satisfactory. If you do? More power to you. I just can't justify spending that much money and time on something that I know isn't even practical to begin with, let alone functional.

I made valid points about the shortcomings of these projectors and how to get around them, and all I've gotten back is hostile retorts trying to prove me wrong with excuses and why the laws of physics don't apply in their hometown roughly around their little workshop. The point of doing something yourself is to create a professional grade product without the professional grade price. A video projector is unfortunately a project not worth doing as a DIY unless you like trying to learn optics the hard way, flush money down the toilet and only want to build a $200-500+ "Gee-whiz Ma! Lookie whut I maeeed!" toy. If you're a hobbiest with that kind of income and want to do that? Again, more power to you... but it doesn't sound like you're one of them, otherwise you could afford a better digital camera and would already own a video projector.

I've got a point to this, but I'll save it since you've all probably labeled me a troll as is. Fine. I don't care. I just wanted to try and help by showing what needs to be done to get these to actually work, and maybe point out to the people on this thread who have dreams of sticking it to "the man" that they won't be anytime soon, at least not with this project. Take care and best of luck to you all.

[jjasniew]

Thanks for the compliment on my image...

Check out these examples currently on ebay -

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=1731671079

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=1730204149

If you won these for $300, you'd be hard pressed to come up with something better for this money. $100 more for a Viewsonic TV tuner/scaler box and you'd have all the video inputs. I own this equipment and should know - I've posted links here showing the performance of this system.

A lesser, but watchable (in the dark...) system could be made from;

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=1730204149

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=1731300942

You should be able to get an image comparable to the one I just posted, for maybe $100 or so - if you win...happy bidding.

Minimizing both expense and effort, I do not think you can touch an assembly of these components - performance wise. If you dont like the OHP form factor? Use your imagination and engineering skills to mutate the combination into some other 3-D shape or size - ALL the necessary components are there.

Want even better performance? Add the optics from (slap on top of) for another $100 or so

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=1351143865

This thing projects light just reflected off a piece of paper - should do a real good job with the itty-bitty light that makes it through the LCD....

Want to just say $^&* - it at a few hundred more? Just make sure you win

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=1352921760

I guarantee you'll not touch the performance of this unit with any LCD based conglomeration. Yes, 6, 7, 8X the cost IS worth 100X the performance. My biggest problem is hanging the 175LB SUCKER from the ceiling - which is an engineering job in itself.

Joe Jasniewski is in no way connected with the sale of the above mentions items. These are mentioned only for the benefit of others who are looking for the best bang for the buck and effort as alternatives to expensive LCD projection units.