You don't have to pay thousands of dollars for a big-screen projection TV set. You can convert your own TV into a homemade projection version with a few cheap items. To do this, create and surround the TV screen with a tube-like box that completely contains the TV's picture image. You also need a fresnel lens (like the type used in stage spotlights) to capture and focus the image. This will project a large-scale image on the wall and give you your big-screen equivalent.
Instructions
1. Measure the length and height of your TV screen. Measure only the screen itself, not the frame surrounding it.
2. Cut out four pieces of cardboard or other sturdy material. All four should be 45cm long. Make two pieces as wide as the TV screen's width and two as wide as the screen's height. Cut one more piece to the same size as the screen and cut a hole in it that is centered and 17cm in diameter.
3. Paint all of the cardboard pieces black on all sides. Wait for the paint to dry.
4. Tape a fresnel lens to the screen-size piece, making sure it covers the entire hole. You do not need to trim the lens. Attach duct tape to opposite ends of the piece to make "tabs," folding the tape over itself so the tabs are non-adhesive.
5. Assemble the other four pieces into a box that is as high and wide as the TV screen and has openings in the front and back. Use duct tape to connect the pieces. Make sure every part of the connecting edges is covered in tape.
6. Tape the box to the TV screen so it protrudes from the screen like a tube. Use enough tape to make a light but tight seal around the screen. Every bit of light from the TV video image must travel through the box.
7. Run more duct tape from the far edge of the box all the way to the top and bottom surfaces of the TV, so gravity won't pull the box off the set. Turn the set upside down, as the lens you'll use flips the picture image.
8. Place the lens piece within the box through the opening, sliding it until it is in the middle of the box. Insert it so that the smooth side of the fresnel lens is pointed toward the screen. Keep the two "tabs" pointing toward the outside so you can grab them and pull the lens back.
Getting the Picture
9. Place the TV on a table about 2 inches from a blank white wall or one covered by a white sheet. Turn off all lights in the room and cover all windows.
10. Turn on the TV to project a picture onto the wall. Move the table and TV back gradually until the picture is large enough for your liking.
11. Adjust the lens by pulling it back and forth within the box until you get a clear picture. If you can't get one, remove the lens and and flip it over, to see if it works better with the rough side of the lens facing the screen.
Tags: duct tape, fresnel lens, wide screen, four pieces, picture image