DIY Video Projector

[vdi_nenna]

Faidzir, opaque projector can be gotten cheaply. From $50 on up for a new unit.

Fiat1, be careful, the type of LCD you're talking about now maybe a graphic LCD. We need video LCDs. The Game Boy may or may not be graphic, I don't know. The LCD needs a video input.

Also, the link you provided to the person who built their own projector look like they used an Opaque projector and modified it.

Vince

[vdi_nenna]

Please consider Case# 3 for your viewing pleasure.

http://www.education.eth.net/acads/physics/light-X.htm

[Type-E]

I wonder what is in the commerical video projectors because it seems that they are 10x more than what it cost to make or am I missing something?

[pa]

Hi!
maybe we could do something better using a DLP or Laser ?
i agree that crt are too complex but maybe a DLP project or a laser prejection could be done ?

¨Pa

[vdi_nenna]

Type-E,

There are some projector lenses that cost more than a projector with a lens. Know what I mean?

If it's made from ground glass, it's going to cost more than a polymer lens. Then there is the barrel for the lens. Is it plastic, aluminum? How many elements are there in the lens? Are the lenses corrected for color?
Is it made by hand?


Buhl Optics makes replacement LCD projector lenses, a division of Navitar.

[Evaas]

I thought I could get away, but the draw of the projector pulled me back in.

on this thread of projector prices, I've even seen light bulbs that cost as much as $800, so surely the full unit is going to be expensive.


on a different topic... I'm still excited about the LED light source, and I want to make it work. I did a little more research, and surpisingly found that LEDs are less efficient than fluorescent and HID lights for broad light specturm (i.e. white light) So it seems that LEDs would not be effective in a full color lcd panel, or through filters to three separate panels.

Where they still seem promising to me is as separate red green and blue light sources for three lcd panels. No light filter involved, and no light is lost through the filters (which seems to be very large in all other three panel solutions) All that is needed is to find the right wavelength LEDs to get the correct color balance. and of course work out all the optics to get the picture to merge.. but who's afraid of a little hard work?? If we can do this to increase the relative efficience of the led's, then a fanless, instant on, long-life solution might still be possible... of course a big array would still be needed for each color, but not as much as for white led's.

whaddya think?

[Evaas]

I'm also assuming that monochrome panels are more transmissive than the full color panels. does anyone have any data on that? I'm still looking to find some cheap panels, and I know they're out there...

[LETSNECK]

HERE'S ANOTHER MESSAGE BOARD. CHECK IT OUT..........http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=006hui

[Gunawan W]

faidzir,
here is opaque projector diagram:


..........................lamp source
..........................beamed to object
..........................|
..........................v
..................../...AAAA
.................../.................H.........................|
................../..................H.........................|
................./...................H.........................|
................/....................H.........................|
.............../.....................H.........................|
............../......................H.........................|
............./.......................^lens
...............==========
mirror 45^.........^object to display............^screen
degrees angle
to base

confused? ignore the dotted, and you'll see the diagram.

My thinking is using this setup with LCD panel as an object,
so we can use common LCD display with backlit shutoff or
use LCD panel with high reflective panel (mirror?) behind.

what do you think?

[Myren]

this is just theory (since they dont make em), but if you got a fast enough monocrome LCD, you could just use one LCD and three difference LCD light sources.

lcd to red channel.
red channel on.
red channel off
lcd to green channel
green channel on
green channel off
lcd to blue channel
blue channel on
blue channel off

you'd need an lcd capable of 3x refresh of whatever you wanted effective refresh to be, but it might work.

as for why projectors cost so god damned ******* much (pardon me, I'm just pissed at their prices), its probably because the projection matrix is probably like an inch by an inch running 1280x1024 with a contrast ratio of 600:1 for a really nice $7000 2500 lumen SXGA projector.

Whereas with something like my solution, you've got a standard 15 inch projector and an overhead projector (OHP). Everything is about 10x bigger and about 100x less prone to error. A glitch in the opticals of something tiny can be a huge problem, but the same glitch in an OHP is completely unnoticable. And you've got about 10x less LED density, and less contrast ratio for the uber-expensive LCD screen.

Matt