| The DIY Projection TV Plan | |||||||
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Step 5
We now have to cut the "focusing board" for the focussing box.
This is basically the screen height and width and will form the front of another
box that fits snugly inside the one we have just made.
Step 6.
Start by marking out the measurements on the cardboard/wood with a ruler an then cut out the focusing board.
Create a straight line from one corner to opposite corner to form a cross on the focusing board, centre the fresnel lens with help from the cross.
Now trace around the fresnel lens so that you have a drawn circle on the focusing board and now cut out the circle.
NOTE : The fresnel lens must fit into the hole.
If you are making this from cardboard, you can angle the stanely knife when cutting the circle so that the hole in back side of the cardboard is slightly larger than the front.
Step 7
Repeat step 2 to make the inside box and remember that the inside box will have to be slightly smaller and only 9 inches deep. Take all pieces paint them black. Both sides if you wish but painting the insides only is essential for a good picture. The Blacker the better. Make sure you use flat or matt black paint.
Step 8
Once the pieces are dry, its time to stick them together. Using
small pieces of duct tape, form the sides of the box (black on the inside) and
stick the small pieces of duct tape on so it holds its shape. Repeat this for
the inside box too.
