NEW projector from INDIA

[fibbrilator]

IF cost is the factor why don't you go with metal halide itself? with 10mm led your total cost will be around1650 + led power source right?
150W metal halide bulb =550rs and ballast = 650rs also you get 13000 lumen's compared to 5500 lumen's from the 110 10mm Leds. Also you get excellent color rendering and color temperature. Most white LED have color temperature around 8500 ( blue tinged) and color rendering of 70.

Just suggesting in case the led's are not upto the mark.

[jaudere]

i agree to this metal halide thing. but i wanted to try for alternative sources like CFLs and LEDs. 2 reasons.
1) temperature
2) electricity consumption
accepted that metal halides do have quite a few good points
but i will need a lot less electricity with LEDs, will save on cooling fans plus no noise from fans.life of LEDs as more than 10000 hours.no need of condenser lens and IR filter. the size of the projector will also be more compact.

anyway, has anyone thought about the 3" LCD displays on many digital cameras ? they are quite cheap, are quite small.

2 problems.
resolution is little less.

i don't know how to attach video input cable ( female RCA) to this screen.

But you can get resolution uotp 640x 480 which i think is fair to watch movies at least. i am not a game loving person.

[jaudere]

got my first projections today with an OHP slide. got 15x magnification at 7 feet screen distance.( the flower is originally 4 cm and the image is 60 cm)

had some problems with LEDs as it was showing a grid on wall. but could solve it with some adjustment of lense. still getting a hot spot in centre. the screen is yellowish ( my wall) and the pics are taken with my mibile camera (1.3 megapixel).

have not strated stripping the LCD

[jaudere]

can anyone tell me how to attch files ? i mean my image size is around 400kb but it does not accept it. what can i do?

[fibbrilator]

Attach file:
Maximum size: 102400 bytes (100KB)
try JPEG compression
last resort zip it up

[fibbrilator]

Does any one know where to get Lexan sheet its pricing and standard size? Has any one here used it? Also why is tempered glass used instead of normal float glass? I have read that both wont block U.V any way.

Thanks,
Gitesh

[badepapa]

Hi Gitesh,

I am facing problems projecting the image.
I got standard OHP fresnel lenses, but I am not able to get a clear image. I am using only one lens b/w light source and LCD, and was trying to figure out at what distance should i fix the lens and LCD.
I don't know the focal length of the lens, so I tried to figure out approx focal length by the method you have suggested in one of your posts(projecting the TV image). Another issue could be my light source reflector as I can see the illuminated part of bulb getting projected in the center and the image of LCD is very dull and hazy. I am attaching the picture of my light source, can you suggest me any improvements to it.

Questions:
1. Do I need to use two lenses ?
2. What should be the approximate distance b/w light source and fresnel lens ?.
3. Do I need to use a round reflector for the light source ?
4. How to decide which side of my fresnel lens is the grooved one ? The lens is plane on both sides (standard OHP fresnel lens).

Hufffffffffffff a long one .....

Thanks for ur help,
Amit

[fibbrilator]

Hi Amit,

I would like to help you out but i would like to know few things first.
1. What is the light source ?
2. What type of Fresnel are you using ( 2 separate or a single fused)
3. what is the focal length of the Fresnel?
4. what triplet/ projection lens are you using?


The light source should be at a distance equal to the focal length of the rear fresnel.If you are using LED light don't use Fresnel.

Th distance between the triplet and the front Fresnel should be roughly equal to the focal length of that Fresnel.

Reflector for the bulb is only to increase the brightness,Projector should work with out it.

I am guessing that you bought the fused Fresnel which is actually
two indivudual fresnel stuck together so there wont be a grooved surface. If you bought from Lensel the focal length will be 216mm & 343mm. You will have to find out which side is which focal length.I have not used this type of fresnel so dont know the exact methord to do that. May be you can focus the sun on a flat surface to get the sharpest dot and measure the distance between the lens and surface. Repeat the same withe the lens on the other side to get focal length.

It would have been easier if you had bought two individual Fresnel.

I also recommend you to read all the previous posts in this thread.

Good luck.

[badepapa]

Hi Gitesh,

Thanks for ur prompt response.
I did not buy lenses from Lensel. I got the lenses from a local OHP spares dealer, and they are the standard OHP lenses. So, dont whether they are fused or not. May be the lens is inside a glass enclosure and thats why there is no rough surface. The lens is approximately 5mm thick. I dont know if I am using correct lenses .

I am in Delhi, how can I get the lenses from lensel ?
They are not responding to my mails.

Oh, I forgot to tell, the light source is 150 W metal halide bulb from Philips.

Thanks
Amit

[jaudere]

hi,

still unable to use jpeg compression (there was no such option) and zipping is reducing size by just 10kb.very odd.
please tell me the method in detail so that i can send images.

another odd thing. just see the distances i have to use to get best image( 20x at 10 feet)

LED panel to Fres 1 (343mm FL): 28 cm

fres1 to LCD: kept in touch with each other

fres1 to fres 2 (216mm FL): 12 cm

fres2 to triplet: have to keep in touch with each other to get best image

you might think that i am doing something wrong. but i think you will accept it if you see the images. another thing is that i am using LEDs. i don't know whether that is making the difference.