Hey,
I need help with a projector idea,
I kinda stuck on working out distances between things,
and what sort of lens to get
And, WHAT does fresnel do?
This is my projector idea
What should the distances be?
The wall to be projected on is 10ft away
Using a 15" TFT Screen
Comments please, i'm quite noob on this
So far i have Found these, just wondering if they are suitable:
15" Sony SDM-X52 TFT Monitor - http://cgi.ebay.co.uk/Sony-15-LCD-Monitor-Screen-SDM-X52-As-new_W0QQitemZ220078871076QQihZ012QQcategoryZ174QQrdZ1QQcmdZViewItem
400W metal halide bulb - http://cgi.ebay.co.uk/new-400w-metal-halide-bulb-grow-bulb-etc_W0QQitemZ290080306926QQihZ019QQcategoryZ20706QQrdZ1QQcmdZViewItem
Freshnel lens - http://cgi.ebay.co.uk/5-Fresnel-lens-for-Projector-of-26x18-Cm-Certified-Mail_W0QQitemZ320080014811QQihZ011QQcategoryZ22610QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
(I know they aren't the right size for 15" screen but couldn't find any bigger)
Any links on lens and freshnel would be helpful
Housing shouldn't be an issue, neither should the screen
Making should be fine
i'm just a little baffled at the theory
I'm hoping this will cost <£70
please correct me if i'm wrong
Help is welcomed as i'm only 16 and very new to this
Thanks a lots
Mike
I need help with a projector idea,
I kinda stuck on working out distances between things,
and what sort of lens to get
And, WHAT does fresnel do?
This is my projector idea
An externally hosted image should be here but it was not working when we last tested it.
What should the distances be?
The wall to be projected on is 10ft away
Using a 15" TFT Screen
Comments please, i'm quite noob on this
So far i have Found these, just wondering if they are suitable:
15" Sony SDM-X52 TFT Monitor - http://cgi.ebay.co.uk/Sony-15-LCD-Monitor-Screen-SDM-X52-As-new_W0QQitemZ220078871076QQihZ012QQcategoryZ174QQrdZ1QQcmdZViewItem
400W metal halide bulb - http://cgi.ebay.co.uk/new-400w-metal-halide-bulb-grow-bulb-etc_W0QQitemZ290080306926QQihZ019QQcategoryZ20706QQrdZ1QQcmdZViewItem
Freshnel lens - http://cgi.ebay.co.uk/5-Fresnel-lens-for-Projector-of-26x18-Cm-Certified-Mail_W0QQitemZ320080014811QQihZ011QQcategoryZ22610QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
(I know they aren't the right size for 15" screen but couldn't find any bigger)
Any links on lens and freshnel would be helpful
Housing shouldn't be an issue, neither should the screen
Making should be fine
i'm just a little baffled at the theory
I'm hoping this will cost <£70
please correct me if i'm wrong
Help is welcomed as i'm only 16 and very new to this
Thanks a lots
Mike
Projector Idea !
The fresnal will not work as i have tried them you need 330 mm fl or bigger .Do a google search you will find them or go to 3dlense they have everything there you need.And read maksoo1 posts or budhi's posts.
The fresnal will not work as i have tried them you need 330 mm fl or bigger .Do a google search you will find them or go to 3dlense they have everything there you need.And read maksoo1 posts or budhi's posts.
Hi Mrmike01 !
if you can get a 13.3" sony LCD, fresnel and lens are easy to do.
13.3" sony LCD is no problem with FFC.
the most OHP have a biger fresnel, two-double fresnel. the size is nice for 13.3" .
and you there is a condenser too, the condenser is not in your pic, but it is important.
and you can get this short arc MHL, 400w too, work in normal magnetic HQI ballast. point light. only $40 each
if you can get a 13.3" sony LCD, fresnel and lens are easy to do.
13.3" sony LCD is no problem with FFC.
the most OHP have a biger fresnel, two-double fresnel. the size is nice for 13.3" .
and you there is a condenser too, the condenser is not in your pic, but it is important.
and you can get this short arc MHL, 400w too, work in normal magnetic HQI ballast. point light. only $40 each
Attachments
I have a DIY projector based on a 15" LCD, and it works pretty well. I used a 400 Watt Ushio UHI-S400DD MH lamp which works with a standard High Pressure Sodium lamp S51 ballast, cap, and ignitor. Ikea sells a polished aluminum partial sphere as a napkin holder, which will work perfectly as a reflector.
I got a 220 mm fl fresnel ("fl" means focal length) and a 550 mm fl fresnel from 3dlens.com. The 220 fl fresnel goes about 1 centimeter before the LCD, and the 550 mm fl frensle goes about 1 centimeter after the LCD.
I use a 22" fl opaque projector lens, for a 95" image from about 12 feet. With your 10 foot throw distance, you might want to use an 18" focal length opaque projector lens to get a larger image. These are surplus and can be found on ebay quite often. They work VERY well with a 15" LCD, since 9" by 12" is very close to the single sheet of paper size they were designed to project.
I have tried several different IR filters, and found the best to be a 5" diameter "hot mirror" from a theatre supply company. It is used to keep plastic lamp filters from melting. Not cheap!
Distances:
1) Lamp filament should be at the center of curvature of the reflector. That is where the center of the sphere would be, if the reflector was a complete sphere.
2) Lamp filament to 220 mm fl fresnel distance is 220 mm. That makes a mostly parallel beam out the other side for the LCD.
3) Fresnel to LCD spacing must be at least 1 cm, or you will see fresnel rings in the image. It can be more, if you like.
4) LCD to 550 mm fl fresnel must be at least one cm (rings), but could be up to about 5 cm. too much and it will mess up the optics by magnifying the image. This fresnel should just direct the rays into the projection lens, not magnify the LCD apparent size.
5) LCD to center of lens / center of lens to screen have a fixed ratio (determined by the projector lens fl) which is:
1/fl = 1/d1 + 1/d2
All distances must be in the same units (usually inches or millimeters)
fl is the focal length of the projection lens
d1 is the LCD to lens distance
d2 is the lens to screen distance
You can use the equation to estimate d1 for the design, and then slide the lens back and forth in its mount to focus the image on the screen. Design it so the lens is at the middle adjustment for your throw distance.
Image size will be 15" * d2/d1
I got a 220 mm fl fresnel ("fl" means focal length) and a 550 mm fl fresnel from 3dlens.com. The 220 fl fresnel goes about 1 centimeter before the LCD, and the 550 mm fl frensle goes about 1 centimeter after the LCD.
I use a 22" fl opaque projector lens, for a 95" image from about 12 feet. With your 10 foot throw distance, you might want to use an 18" focal length opaque projector lens to get a larger image. These are surplus and can be found on ebay quite often. They work VERY well with a 15" LCD, since 9" by 12" is very close to the single sheet of paper size they were designed to project.
I have tried several different IR filters, and found the best to be a 5" diameter "hot mirror" from a theatre supply company. It is used to keep plastic lamp filters from melting. Not cheap!
Distances:
1) Lamp filament should be at the center of curvature of the reflector. That is where the center of the sphere would be, if the reflector was a complete sphere.
2) Lamp filament to 220 mm fl fresnel distance is 220 mm. That makes a mostly parallel beam out the other side for the LCD.
3) Fresnel to LCD spacing must be at least 1 cm, or you will see fresnel rings in the image. It can be more, if you like.
4) LCD to 550 mm fl fresnel must be at least one cm (rings), but could be up to about 5 cm. too much and it will mess up the optics by magnifying the image. This fresnel should just direct the rays into the projection lens, not magnify the LCD apparent size.
5) LCD to center of lens / center of lens to screen have a fixed ratio (determined by the projector lens fl) which is:
1/fl = 1/d1 + 1/d2
All distances must be in the same units (usually inches or millimeters)
fl is the focal length of the projection lens
d1 is the LCD to lens distance
d2 is the lens to screen distance
You can use the equation to estimate d1 for the design, and then slide the lens back and forth in its mount to focus the image on the screen. Design it so the lens is at the middle adjustment for your throw distance.
Image size will be 15" * d2/d1
The fresnel lenses are needed to direct the light through the entire surface of the LCD, and then into the projection lens. Without the first (condensor fresnel) you would only get a small circle in the center of the LCD lit. Without the second (field fresnel) you would get a very dim image because most of the light going through each pixel would not reach the projection lens.
You can put both fresnels together at least one cm before the LCD, or you can split them apart with the condensor fresnel one cm before and the field fresnel 1 cm after the LCD.
You can put both fresnels together at least one cm before the LCD, or you can split them apart with the condensor fresnel one cm before and the field fresnel 1 cm after the LCD.
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