Watching TV from a projector can be expensive, especially if you desire a 150-inch projection image, which is large. However, it is possible to construct your own version of a 150-inch projector if you have an old CRT-based (cathode ray tube) TV set. You might not get the same picture quality as an actual projector, but you can still get a decent picture with a plastic fresnel lens. Remember that a 150-inch screen is the measurement of the screen's diagonal, not the horizontal or vertical, edge.
Making the Projector
To build the projector, construct a cardboard frame that is the same height and width of your CRT TV's screen and about 22 centimeters long--think of a cardboard box with two sides removed. Paint the entire frame black and tape it to the TV so it "sticks out" from the screen; place sturdy duct tape all the way around the edges so no light from the screen cracks through, then tape the frame's front edges to the top and bottom of the TV, to support the frame. You need one more single piece of cardboard cut to the screen's size. Cut a hole 19 centimeters in diameter in the exact center of this piece and tape a fresnel lens to the piece. Insert this piece with the lens into the TV screen's frame.
Positioning and Focus
Once the "projector" is finished, you must find the precise location to project a 150-inch size image. Given whatever size your TV screen is, this can vary. Turn the TV set upside down, as the fresnel lens inverts the image (the screen will temporarily be purple or green unless you left the TV off for at least a half hour). Place the projector on a table, point it at a blank wall and turn the set on. Move the set around until you have the desired 150-inch projection. Once that is in place, adjust the position of the fresnel lens inside the projection frame until you have a focused, clear image.
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