| Author | Message | ||
     mchild Rating: N/A |
I wanted to shed some light on this subject as I have been dabbling with this for 20 years. I have bought several kits over the years and wanted to share my experience. My current system uses two (high quality) fresnel lenses (though this is not the system that I would recommend, see later). They cost more than the $10 ones that you mostly see advertised, however. (What a surprise quality costs money). It works fantastic under the right conditions. First a TV is not going to give you the lumens that ANY LCD/CRT projector will, period. That is the limitation of using a TV as a projector source - Lumens. Period. That said there are ways to make it acceptable to excellent. Use a good TV. Computer monitors are not nearly as bright as TV's, they will not work. One serious limitation has always been the curved TV screen. It would make the image focused only in the center with the image being more blurry the closer you get to the edge. The only solution used to be trying to make curved screens. This is no longer an issue thanks to Sony WEGA TV's. If you use anything other than a WEGA you will not get good results. The screens are perfectly flat and the image will be sharp from edge to edge. I have not had very good luck with 19" TV's. It always made the TV too close to the screen, making it hard to view. (It would be ideal if you were going for a rear projection system however). I use only 13" TV's. This is especially true now that Sony makes a 13" perfectly flat WEGA. In my opinion that is the only TV to use. The system will only work in COMPLETE darkness. The TV just doesn't have enough lumens to allow ANY light at all. (But, I only watch movies at night anyhow, so no big deal) Use a good screen. Don't use a white wall. Don't use a sheet. Use a commercial projection screen. I use Da-lite products. Use a Glass Beaded or High Power screen. This will give a screen gain of 2.5 - 2.8. This is VERY important. Remember lack of lumens is the problem with this system. You need a high gain (reflects a lot of light) screen. These screens are cheap. A 100" screen can be had for well under $200. And besides when/if you get a real projector you will already have the screen. Don't use mirrors. They distort the image and absorb valuable light. Take your TV to a repair shop and have the technician reverse the wires to the vertical yoke. This will make the image upside down but will not flip it left to right. They should do this for $20. It will take them five minutes. My TV repair man did it for free. The best system that I know of doesn't use fresnel lenses at all but uses a multi-lens glass lens like used in crt projectors. It costs a couple hundred bucks however. (You get what you pay for) If you take these points into consideration you can have an awesome projector for a very cheap price. Since the arrival of 13" Wega's, I have been absolutely thrilled with the results. Feel free to email me if you wish. Enjoy! | ||
| Anonymous Rating: N/A |
I suppose the one advantage to a TV projector over an LCD projector would be that there would be no bulbs to purchase, which are expensive. How large was your screen? Could you give us a source link for good glass lenses and details on that setup. Has anyone tried to build an LCD projector from a small LCD television? (Besides Eric L who outlined his project.) | ||
| Stee1HeD Rating: N/A |
Ok, I am currently trying to build an LCD projector. One of the biggest things I was concerned with was getting a portable TV that was backlit and could be disassembled and the back light taken off. I found one. The RCA L2501. I went to Best Buy and these puppies blew away the others they had. The picture quality and pixels in the tft active matrix display was way better than the others. Don't take this to matter of factly because I cannot remember exactly but I believe it said it had 163,xxx pixels. Just for kickers I took the squareroot of that and get around 400, so if the screen where perfectly square it would be around a 400x400 display. Not too shabby. Anyways, it was $130. I got it on EBAY for $36. That's right $36...thirty six dollars. I also bought a portable slide projector for about $32 and a portable movie screen for $20. Ebay rocks. I haven't got the screen yet but I have the other stuff. So I've put in around $90 for the thing so far. I need to get some mounts and maybe a housing kit and fans. Today I took apart the tv and it is exactly what the system requires. Eric (April fools man) mentioned disconnecting the display and somehow making the connection longer by soldering wires or whatever. Well the driver board for the display has a pretty long ribbon cable while the display to the driver board has a short ribbon cable. So I am bringing the display and driver board through the front window. No electronics fiddling required. I couldn't wait to see it working so I held the system in one hand and put the lcd in the projector and shined it on the wall. I liked what I saw (real informative stuff huh?). I plan on building a little edge mount gizmo to hold the driver board and display and connect that to the main unit somehow. I also need to get some fans for the slide projector. I recommend going to Best Buy if you have one and check them out. They are exactly what the system Eric described requires. Perhaps they can be found on Ebay. I hope this helps some people because it was my biggest hang up. The only part that may be a little tricky is desoldering the backlight shield from the display. Both my soldering irons stopped working for some reason so I used a light touch with a blow torch (hehehe). The rest is just screws and plastic retaining clips. I'll update when I get a chance to finish this thing. | ||
| Stee1HeD Rating: N/A |
I was wrong, only 116,xxx pixels. Still a lot more than any others there. | ||
| Anonymous Rating: N/A |
hv any of you visited game arcades? they hv many game machines tt hv big screens but are actually magnified image from a small monitor hidden below. they use mirrors & some sort of big magnifying lens (fresnel?) to produce a big image ( abt 30+") from probably a 14" monitor. i guess tt's a reasonable compromise for big screen display, & stereoscopy isn't a problem since they use normal monitors. |
