**Some Math - More questions**
Thanks for the reply.

NOTE:

I am trying to make this simple so future projects can find a easy way to determine this information (...sorry if it seems basic)

OK, to review this is what I know.

1. DIY seems to be the only one with a fresnel that I can use with my LCD.

=========================================================================

2. Lets Calculate the lense:

*Big thanks to Guy for the formulas from a previous post*

Known information:

I want 100" screen

Throw (lense to wall distance) = 10'

LCD size = 16"

Soo....

The magnification would equal = 100/16 = 6.25

Plugging this information into this eq:

fl = throw / (M+1) = > => (10 feet * 304.8 mm/foot) / (6.25 + 1)

works out to:

3048/7.25 = 420.41 mm focal length lens

=========================================================================

So far soo good...

Now that is a pretty big lense...and DIY also seems to be the only one that can handle something that big. Now this lense is not without controversy. ROX has been debating it's usefulness in a number of posts...but...one person got it to work:

(Diyeitor17) -

http://diyprojectorcompany.com/phpBB2/viewtopic.php?t=381)

Although he took it apart...and it now seems to work OK = lots of extra work.

I guess that is my only option right now...roll the dice and see what happens.

It looks like I can be the test subject on this issue.

UNKNOWN:

1. I can't seem to figure out the formula to determine the LCD to lense.

I have seen it in action...but still cannot figure it out.

2. The spacing of the [fresnel] to the [LCD] - > Formula? Trial and error?

Note: I plan on using only one to simplify things

3. The [light] to the [fresnel] - > Formula? Trial and error?

How do you make the $20 version?

The quest continues!