Hi Vijay,
Good to know you are in Bangalore. Have you brought all the projector parts from chennai? You can get a frame for you LCD done at electrical shops where Electrical plastic switch board panels are made.You can get it done in acrylic or Hylem.Best is to carry your orginal LCD frame with you.
Sure shall wait for the photos and LCD details.
Happy building
Take care,
Gitesh
Good to know you are in Bangalore. Have you brought all the projector parts from chennai? You can get a frame for you LCD done at electrical shops where Electrical plastic switch board panels are made.You can get it done in acrylic or Hylem.Best is to carry your orginal LCD frame with you.
Sure shall wait for the photos and LCD details.
Happy building
Take care,
Gitesh
Ahh. this thread seem to be inactive for a longer time. yea i am almost completed my PJ work. there are lots of miscalculations in building the box 
i dont have space to put the controller inside the box. the good part is i have found an alternate way to hold the plywoods together instead of using nails. i hope by this week end i can complete and post the results. And by the way my box is small
regards
vijay
i dont have space to put the controller inside the box. the good part is i have found an alternate way to hold the plywoods together instead of using nails. i hope by this week end i can complete and post the results. And by the way my box is small regards
vijay
Congrats maks. great work (including the aesthetics)
i am an intensivist( ICU doctor), visiting the site for the first time today.
went throught the the projector thread.
did not understand one thing. in Buddhi's original scheme, there was a lens between the light source and the mirror. have you used it or no?
i am an intensivist( ICU doctor), visiting the site for the first time today.
went throught the the projector thread.
did not understand one thing. in Buddhi's original scheme, there was a lens between the light source and the mirror. have you used it or no?
Hi Maks,
If we use fresnel lens with shorter focal lengths, our design can be even compact. Isn't it ?
Also wanted to know why do we use the second fresnel of focal length 330 mm, which is larger than the other one(220 mm) near the light source? Do we have any benefits of using fresnel of longer focal length? Or, we can still go with a shorter focal length lens.
Thanks
Amit
If we use fresnel lens with shorter focal lengths, our design can be even compact. Isn't it ?
Also wanted to know why do we use the second fresnel of focal length 330 mm, which is larger than the other one(220 mm) near the light source? Do we have any benefits of using fresnel of longer focal length? Or, we can still go with a shorter focal length lens.
Thanks
Amit
Bangalore Metal halide dealer
I have bought the metal halides and ballast for my projector. The specifications are below.
Lamp model no :OSRAM HQI-T 250/D
Lamp wattage :250 W
Luminous flux :20000 lm
Luminous efficacy :80 lm/W
Colour temperature:5300 K
Colour rendering :1A (greater than 90)
Base :E40
Length l : 225 mm
Outer diameter : 46 mm
Price for the Lamp was 800Rs
Original Osram ballast for 250 w lamp costs 1450 Rs.
The shop owner was very helpful, he suggested to take a clone ballast which they manufacture under the brand name STARLITE. It comes with a 1 year warranty so i bought the same.The price for the ballast was 850Rs without tax.
They stock all types of Osram lamps including 150W Power ball series in G12 base which is one of the most compact lamps best suited for projectors.But the price for that was 1500rs.
I explained the shop owner the purpose and our hobby and he has offered support regarding lighting part.If any one enquires tell them it is for building LCD projector.
Below is the contact details of the shop.
SRI Vinayaka enterprises,
No32,
A.M lane,
Basettypet,
B.V.K Iyengar road,
Bangalore-560053.
Tel: 080-41249599.
Email: starlite@wyapaar.com
Regards,
Gitesh
I have bought the metal halides and ballast for my projector. The specifications are below.
Lamp model no :OSRAM HQI-T 250/D
Lamp wattage :250 W
Luminous flux :20000 lm
Luminous efficacy :80 lm/W
Colour temperature:5300 K
Colour rendering :1A (greater than 90)
Base :E40
Length l : 225 mm
Outer diameter : 46 mm
Price for the Lamp was 800Rs
Original Osram ballast for 250 w lamp costs 1450 Rs.
The shop owner was very helpful, he suggested to take a clone ballast which they manufacture under the brand name STARLITE. It comes with a 1 year warranty so i bought the same.The price for the ballast was 850Rs without tax.
They stock all types of Osram lamps including 150W Power ball series in G12 base which is one of the most compact lamps best suited for projectors.But the price for that was 1500rs.
I explained the shop owner the purpose and our hobby and he has offered support regarding lighting part.If any one enquires tell them it is for building LCD projector.
Below is the contact details of the shop.
SRI Vinayaka enterprises,
No32,
A.M lane,
Basettypet,
B.V.K Iyengar road,
Bangalore-560053.
Tel: 080-41249599.
Email: starlite@wyapaar.com
Regards,
Gitesh
Attachments
I am going in for my first projector.
will be using LEDs as light source(don't know how well it will work but want to experiment). will be using a panel with 100 LEDs with each giving out 50000 mcds right behind the LCD screen.
will use 6" LCD screen.
slightly confused about lenses.
does anyone know where to get TV projection lens from?
a probably stupid question:
can a camera lens be used as a projector lens? a lens with 85mm focal length and f1.8 speed?I am a doctor & almost zero at optics. what i thought was that only direction of light will change as compared to camera. rather than gatherintg light from wide field and concentrating it on photo film, the lens should gather light from LCD and transmit to a broad field.
won't be using fresnels.
vikram
will be using LEDs as light source(don't know how well it will work but want to experiment). will be using a panel with 100 LEDs with each giving out 50000 mcds right behind the LCD screen.
will use 6" LCD screen.
slightly confused about lenses.
does anyone know where to get TV projection lens from?
a probably stupid question:
can a camera lens be used as a projector lens? a lens with 85mm focal length and f1.8 speed?I am a doctor & almost zero at optics. what i thought was that only direction of light will change as compared to camera. rather than gatherintg light from wide field and concentrating it on photo film, the lens should gather light from LCD and transmit to a broad field.
won't be using fresnels.
vikram
One easy way to validate the lens is by projecting the image from a T.V on to a wall. You can do this by taking a card board sheet / box as big as the T.V screen. Fit in the lens in the center of the card board.The tv should be roughly 6 feet away from the wall.Now put the lens & card board device in front of the T.V with around 1 feet between the them.Adjust ast the distance till you get a clear image projected on the wall.When you get the sharpest image measure the distance between the lens and the T.V that will be the focal distance of the lens.
I have attached an image showing how to do it.If there is no projected image it is very probable that your lens wont work.
IMHO 100 LED is too less. Pack as much 5mm LEDs as possible on to a general purpose pcb as big as your LCD screen.
You can get the projection lens/ triplet from LENSEL Pune or OPTICS & ALLIED Bangalore.See past posts.
Happy building,
Gitesh
I have attached an image showing how to do it.If there is no projected image it is very probable that your lens wont work.
IMHO 100 LED is too less. Pack as much 5mm LEDs as possible on to a general purpose pcb as big as your LCD screen.
You can get the projection lens/ triplet from LENSEL Pune or OPTICS & ALLIED Bangalore.See past posts.
Happy building,
Gitesh
Attachments
have you seen this?yhttp://www.allinbox.com/concours2006/pj2006/34_RETROLED_de_Salamander
so just wanted to give it a try. if it does not work, wil use conventional MH lamp. couldn't calculate lumens given by 100 LEDs giving 50000mcd each.
has anybody tried xenon auto lamps with its reflectors?look pretty powerful on roads atleast( the white ones which are there on skoda).
does anyone know where to get TV projection lens. Gitesh, i have seen something different under the name of TV projection lens. what you are saying is right but those lenses are same as fresnels i guess.
what i have seen on net and available in US is a 114mmFL with f1.4 lens
vikram
so just wanted to give it a try. if it does not work, wil use conventional MH lamp. couldn't calculate lumens given by 100 LEDs giving 50000mcd each.
has anybody tried xenon auto lamps with its reflectors?look pretty powerful on roads atleast( the white ones which are there on skoda).
does anyone know where to get TV projection lens. Gitesh, i have seen something different under the name of TV projection lens. what you are saying is right but those lenses are same as fresnels i guess.
what i have seen on net and available in US is a 114mmFL with f1.4 lens
vikram
Very roughly speaking 1 mcd = .001 lumens. Try googling the following key words.
convert millicandela to lumens
or calculate here
http://led.linear1.org/lumen.wiz
By the way which is the LED you have in mind?
Fresnel lens and triplet lens are not the same. Fresnel lens resemble a large sheet of plastic. Triplet lens is also known as OHP projection lens. Most of us use Triplet lens for the project.
convert millicandela to lumens
or calculate here
http://led.linear1.org/lumen.wiz
By the way which is the LED you have in mind?
Fresnel lens and triplet lens are not the same. Fresnel lens resemble a large sheet of plastic. Triplet lens is also known as OHP projection lens. Most of us use Triplet lens for the project.
I am using 10 mm LEDs 50000mcd each. 100 such pieces on a13cmx9cm PCB. the PCB surface will almost be fully covered by LEDsand the size will be same as LCD screen.
we need fresnel as well as triplet for the projector.
fresnel immediately behind the LCD screen and the triplet gathers light converged by fresnel and projects it.
even the OHP has fresnel and a singlet or triplet combination.
vikram
we need fresnel as well as triplet for the projector.
fresnel immediately behind the LCD screen and the triplet gathers light converged by fresnel and projects it.
even the OHP has fresnel and a singlet or triplet combination.
vikram
single fresnel
a thought:
we need the fused fresnel lens in the projector or we use 2 fresnels, one behind LCD and the other in front of LCD. but this is needed for Point source of light only ( to converge diverging light rays).
if i am using LED panel of same size of that of LCD screen, and since LEDs throw light in a single direction only, shall i consider my light source as a point source or a source which provides parallel beam rather than diverging beam?
if it is a parallel light beam, i think a single fresnel in front of LCD will do. this is important as single fresnels are available at Lensel optics.
in one of the other threads, a man tried LEDs but failed. he said that his LEDs gave adequate illumination but there was some problem with optics which he could not figure out.
what i think is that it failed bcause he used fused fres with LEDs. that was quite old thread(2001) so have not aske him yet.
Vikram
a thought:
we need the fused fresnel lens in the projector or we use 2 fresnels, one behind LCD and the other in front of LCD. but this is needed for Point source of light only ( to converge diverging light rays).
if i am using LED panel of same size of that of LCD screen, and since LEDs throw light in a single direction only, shall i consider my light source as a point source or a source which provides parallel beam rather than diverging beam?
if it is a parallel light beam, i think a single fresnel in front of LCD will do. this is important as single fresnels are available at Lensel optics.
in one of the other threads, a man tried LEDs but failed. he said that his LEDs gave adequate illumination but there was some problem with optics which he could not figure out.
what i think is that it failed bcause he used fused fres with LEDs. that was quite old thread(2001) so have not aske him yet.
Vikram
Re: single fresnel
When you use LED as light source single fresnel is enough.You don't need the condenser Fresnel as the light source through the LCD will be parallel. IMHO 5mm LED will be better than 10mm led as more no of smaller LED will provide even illumination. Also see the specification of the LED for color temperature and color rendering index.Ideally color temperature should be between 4500K and 6500K. and color rendering above 80.
jaudere said:
When you use LED as light source single fresnel is enough.You don't need the condenser Fresnel as the light source through the LCD will be parallel. IMHO 5mm LED will be better than 10mm led as more no of smaller LED will provide even illumination. Also see the specification of the LED for color temperature and color rendering index.Ideally color temperature should be between 4500K and 6500K. and color rendering above 80.
LED cost
I know 5mm would be better than 10mm. but look at the cost.
( at lamington road, Mumbai)
5mm 22000 mcd : rs 16 each
10mm 50000mcd: rs 10 each.
probably 10mm have narrow angle and thats why mcd value is high. but that doesn't matter for me as i am using tightly packed panel. it also means that reflectors won't be of any use due to the narrow angle.
now if you look at the total cost, you can fit maximum 110 of 10 mm LEDs on 13cmx9cm PCB. if i use 5 mm LEDs, i will need about 400 or more LEds. plus i am not going to solder it myself. the person doing this will charge me rs 5 per LED. so you can see how the cost will go up.
so what i did finally is that i bought 2 single fresnels( from lensel) i will try with single initially. if i don't get good image, i will try to put in second fres behind LCD. or may be putting a condenser between LEDs and LCD will help. i have to do trial and error.
if everything goes well, my project won't cost more than rs 7000. let's see
Vikram
I know 5mm would be better than 10mm. but look at the cost.
( at lamington road, Mumbai)
5mm 22000 mcd : rs 16 each
10mm 50000mcd: rs 10 each.
probably 10mm have narrow angle and thats why mcd value is high. but that doesn't matter for me as i am using tightly packed panel. it also means that reflectors won't be of any use due to the narrow angle.
now if you look at the total cost, you can fit maximum 110 of 10 mm LEDs on 13cmx9cm PCB. if i use 5 mm LEDs, i will need about 400 or more LEds. plus i am not going to solder it myself. the person doing this will charge me rs 5 per LED. so you can see how the cost will go up.
so what i did finally is that i bought 2 single fresnels( from lensel) i will try with single initially. if i don't get good image, i will try to put in second fres behind LCD. or may be putting a condenser between LEDs and LCD will help. i have to do trial and error.
if everything goes well, my project won't cost more than rs 7000. let's see
Vikram
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