alright, I've been to many forums and have, myself, hit people with the search...but this forums set-up is alittle akward (no group threads, i.e. "show off you project," "worklogs"....) and the search button never seems to find anything remotely close to what I'm in search for...
anyway....I understand many people making 7" lilliput DIY projectors...I just have a composite/dvd 7" (not lilliput) and what I was to know is:
1) dimensions of the box
2) build cost...average (excluding the lcd)
3) and picture quality...
I would also greatly appretiate it if any of you that have built one and arranged a thread going into explaination of the entire process could send me a link to your page 🙂
IMO I have been very helpful for the short time I have been here and what I ask for isnt too much.
anyway....I understand many people making 7" lilliput DIY projectors...I just have a composite/dvd 7" (not lilliput) and what I was to know is:
1) dimensions of the box
2) build cost...average (excluding the lcd)
3) and picture quality...
I would also greatly appretiate it if any of you that have built one and arranged a thread going into explaination of the entire process could send me a link to your page 🙂
IMO I have been very helpful for the short time I have been here and what I ask for isnt too much.
also, the wall I have set up to project onto is 8'(height) by 12'
and the distance I would like to locate the project is 16'...
If I was going for a wide screen, how large could I go while still resuming a sharp image?
thanks a lot.
-rob.
and the distance I would like to locate the project is 16'...
If I was going for a wide screen, how large could I go while still resuming a sharp image?
thanks a lot.
-rob.
I remember seeing a post over at diylabs that had recommended max projection sizes for a variety of lcd sizes and resolutions. I wish I could remember more about it to find it. You are right...the search functions definitely leaves some things to be desired. If I remember correctly, I believe your optimal size for a 7" is around 80". Don't quote me on this though. I would say that you could probably shoot for 100 and still be fine. For 100 inches, you would need a 300mm F.L. lens. Your best bet would be the 80mm triplet from diyprojectorcompany.com . When it comes to sizes, choose your fresnels, lens and light source and then do the math. Also, before you build the frame, verify the F.L. of your specific fresnels. There doesn't need to be a set "pattern" for your projector. That is what makes it fun.
Thank you! that helped a lot. wasnt the answer I was hoping for(was hoping to get a bigger screen out of it) but thanks for your help..
I have a 52" RCA HDTV widescreen and wanted a screen 110"-120" in my basement.
is an 80" out of a 16' run? or is 80" as big as I'll get it without looking like crap from any distance?
I know there isnt a pattern but I was hoping for an approximent size so I wasnt wasting material and time...😀
Thanks again.
-Rob
I have a 52" RCA HDTV widescreen and wanted a screen 110"-120" in my basement.
is an 80" out of a 16' run? or is 80" as big as I'll get it without looking like crap from any distance?
I know there isnt a pattern but I was hoping for an approximent size so I wasnt wasting material and time...😀
Thanks again.
-Rob
not really 16 foot throw!
Unless you plan to make a hole through the wall to mount your projector in the room next door, you won't be getting a 16 foot throw distance. If you use a design where the light travels up through the LCD and then is folded by a front surface mirror before it hits the lens, then you could probably get around a 14 foot throw distance.
With a 14' throw, 7" LCD, and a 300 mm focal length lens, you would get a 92.6" diagonal image. Here are some other possibilities:
290 mm lens => 96" image
255 mm lens => 110" image
235 mm lens => 120" image
Personally, I would recommend the 300 mm fl lens, because this is the most common size for DIY projectors (a legacy from overhead projectors), and it is so easy to get matching fresnels.
Keep in mind that the screen brightness falls at the square of the diagonal size, so a 92.6" image is 68% brighter than a 120" image using the same projector. (Even with the 92.6" image, I would go for a 400 Watt lamp. 250 Watt lamps need a very dark room to look good at this size.)
As for the maximum size, I think the 7" Lilliput is 800 by 480 pixels? That is way more then standard TV, so any source with lower resolution than HDTV should look great. (If you can see the screendoor, then you are sitting way too close!)
BTW: Don't buy a bunch of parts before you do the math. You do need a field fresnel (the second one) that somewhat matches your projection lens. (A 330 mm fl is a perfect match for a 300 mm lens, 14' throw, in a split design.)
Unless you plan to make a hole through the wall to mount your projector in the room next door, you won't be getting a 16 foot throw distance. If you use a design where the light travels up through the LCD and then is folded by a front surface mirror before it hits the lens, then you could probably get around a 14 foot throw distance.
With a 14' throw, 7" LCD, and a 300 mm focal length lens, you would get a 92.6" diagonal image. Here are some other possibilities:
290 mm lens => 96" image
255 mm lens => 110" image
235 mm lens => 120" image
Personally, I would recommend the 300 mm fl lens, because this is the most common size for DIY projectors (a legacy from overhead projectors), and it is so easy to get matching fresnels.
Keep in mind that the screen brightness falls at the square of the diagonal size, so a 92.6" image is 68% brighter than a 120" image using the same projector. (Even with the 92.6" image, I would go for a 400 Watt lamp. 250 Watt lamps need a very dark room to look good at this size.)
As for the maximum size, I think the 7" Lilliput is 800 by 480 pixels? That is way more then standard TV, so any source with lower resolution than HDTV should look great. (If you can see the screendoor, then you are sitting way too close!)
BTW: Don't buy a bunch of parts before you do the math. You do need a field fresnel (the second one) that somewhat matches your projection lens. (A 330 mm fl is a perfect match for a 300 mm lens, 14' throw, in a split design.)
I do plan on having the unit in the next room (so you dont hear the fans, ect...) so it would be a 16' throw, thank you for those measurements. that should pretty much take care of everything. thanks again.
jeez guy. in all of your post's, its like you answer the question and then you read their minds and answer their next questions! your very helpfull and I greatly appretiate it.
actually I just measured the room. its 13' by 17'.... and I dont want a projector in the middle of the room on the celling...I hope the long run doesnt loose too much light.
throw distance
Throw distance by itself, has almost no effect at all on the brightness! (Unless you and your buddies are all smoking cigars in your home theatre. 😀 )
But with a particular lens and LCD size, the throw distance determines the screen image size. THAT spreads all the available light over the image area, so THAT determines the brightness.
To make that a bit clearer: If you use a particular lens to give you a 100" diagonal image from 10 feet, and then use a different lens to give you a 100" diagonal image from 30 feet, both images would have the same brightness.
For image sizes from 17', you can just multiply those sizes I gave you by 17/14. So a 300 mm lens would give you a 112.4" image.
Throw distance by itself, has almost no effect at all on the brightness! (Unless you and your buddies are all smoking cigars in your home theatre. 😀 )
But with a particular lens and LCD size, the throw distance determines the screen image size. THAT spreads all the available light over the image area, so THAT determines the brightness.
To make that a bit clearer: If you use a particular lens to give you a 100" diagonal image from 10 feet, and then use a different lens to give you a 100" diagonal image from 30 feet, both images would have the same brightness.
For image sizes from 17', you can just multiply those sizes I gave you by 17/14. So a 300 mm lens would give you a 112.4" image.
We could quote you sizes all day long... how about going here and playing around with the calculator for yourself. http://www.diyprojectorcompany.com/theory/calculator.htm
If you are looking for supplies, go to these sights and browse around for miscellaneous stuff to help. Surplus shed has objective lenses that alot of people use in their projectors.
www.surplusshed.com
www.electronicsgoldmine.com
If you are looking for supplies, go to these sights and browse around for miscellaneous stuff to help. Surplus shed has objective lenses that alot of people use in their projectors.
www.surplusshed.com
www.electronicsgoldmine.com
I'm sorry, I gave the wrong address for electronics goldmine.
Here is the correct one.
http://www.goldmine-elec-products.com/
Here is the correct one.
http://www.goldmine-elec-products.com/
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