REGULAR TV / LCD PROJECTOR

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By the time you are done going through all this information, you should be able to build a video projector that will work as well as any one of the brand name LCD video projectors that cost hundreds to thousands of dollars, for less than $300.  To get started you need to know how these projectors work.  It's quite simple really; the projector uses a different light source other than the LCD monitor.  It magnifies the picture with one or more lenses and with the power of an alternate light source.  It then projects it onto a screen for viewing.

Why use an LCD projector over a standard CRT/TV Fresnel lens magnified projector?  These types of projectors are large and heavy, and if you ever tried to make one, you will have found out that the picture quality is usually poor regardless of the type and size of lenses used.  Even if the room is pitch black!  The light source from a standard TV is just not strong enough to give you a clear, bright picture.  If you try and use a different light source, you'll find that the glass screen of the TV causes enough of a glare to overshadow the picture and you wind up not seeing anything.  You can get anti glare polarizing shields for a standard TV, but the cost is very high in comparison to an LCD.  LCD's, or Liquid Crystal Display TV's are perfect for these types of projectors because the anti-glare screen comes with the TV, and it can be adjusted for different light conditions.

Choosing an LCD monitor for your projector:  A decent LCD monitor which ranges in size from 2 to 5 inches diagonally, can be purchased via many internet or traditional vendors for under $100 USD.  For $20 more, it's possible to find one that will accept NTSC, PAL and SECAM, so it will be more useful to people in areas other than North America.  The LCD's will come with standard RCA video inputs, sometimes expanded from a 1/8th inch jack.  Pixel count, and therefore resolution and picture quality is quite important.  The better quality the LCD, the better the final projected image will be.  If you're choosing this method of building a projector, you don't have to worry about taking your LCD monitor apart, because this projector uses a direct reflection method, rather than a pass through transitive method that would require you to take the backlight off your LCD monitor.

Here you will find plans, wiring diagrams, and a complete list of all parts & materials needed, with step by step instructions to guide you through the construction process.  After going through all of the information and plans, if you decide that you're not up to the challenge of building a projector similar to the one shown, there is information on where to buy a projector ready made, and explanations on how to set it up for use with your LCD monitor.

Tools:

  • Table saw
  • Jig saw
  • Drill with 1/2 inch wood bit, Philips head screw attachment and hole saw bits. Saw bit size depends on lens assembly DIA.
  • Measuring tape
  • Wire cutters
  • Razor utility knife
  • Electrical tape, masking tape
  • Wire nuts

Required Parts:

  • 3 to 5 inch LCD monitor
  • 1 - 4 inch fan
  • 2 porcelain light sockets
  • 1 - 6 inch square mirror
  • 2 light bulbs 75 - 100 watts each
  • 2 small light switches
  • 1 - 6 ft. extension cord
  • Lens
  • Cardboard mailing tube. Size and diameter depends on lens DIA.

13 wooden pieces

  • 2 - 12" x 8 1/2" x 3/8" plywood - top and bottom pieces
  • 2 - 7 3/4" x 7" x 3/8" plywood - sides
  • 2 - 7" x 12" x 3/8" plywood - front and back
  • 1 - 5" x 5" x 3/8" plywood - top for fan cover
  • 2 - 3" x 5" x 3/8" plywood - sides for fan cover
  • 1 - 3" x 4 1/4" x 3/8" plywood - front for fan cover
  • 2 - triangle pieces for mirror mount - measure from plans
  • 1 - 5" x 5" x 3/8" plywood -for mirror mount
Projector Assembly:

The measurements in this set of plan are of a general size. In accordance with the parts that we used to build a projector. You may have to make modifications for the parts you buy.

To start with, cut out all of the holes in each piece according to their location in the plans. The parts you use will determine lens barrel, light switch and fan vent hole sizes. We only giving you the location on the plans. Paint all inside pieces of the box with flat black paint. Allow paint to dry.

Assemble the front, back, sides and top with nails and glue. Leaving the bottom off. Next glue and nail the 3 pieces of the mirror mount together and then glue it into position according to the plans. Mount the mirror to the mirror mount with glue or double-sided tape.

Next mount the light sockets and switches to the back wall according to their locations in the plans. Next mount the fan on top with air direction going into box. Assemble the 4-piece fan box cover, Top and 3 sides with glue and nails. Mount it over the fan with the open side facing the back of the projector.

Next follow the wiring diagram and wire all the together. Wire it all together on the extension cord. Make sure that the wiring is pulled back so that it does not interfere with the TV and lens function. Put the light bulbs in next. Test to make sure the system is working.

Finale slide the bottom piece in place and attach it with wood screws only. So it can be removed later dates for mirror cleaning and bulbs changing.

How to set up the Projector:

Start with setting up the system in the chosen location. Distance from screen depends on the picture size you want. Next hook up your audio and video. Audio to either stereo system or just amplified speakers. Video to VCR or other video source. Other than that you'll have 2 adjustments to make. First and most important adjustment is the glare screen adjustment. We suggest using very small adjustments until the picture comes in. Then the 2nd adjustment to make is the focus. You must slide the lens barrel in or out to adjust the focus. When you have both adjustments set up together do mini adjustments as needed to get the picture perfect.

Finale and most important! Never run the projector without fan. The heat that can build up in the projector box can and will damage to your LCD without the fan to cool the box down. And always after use of the projector! Shut off light and left the fan run for a while to cool the system down.

Choosing the right lens & lens barrel assembly:

To start with, in choosing the right lens. You'll need a lens with focal length of 5 to no more than 10 inches. A double convex lens, also known as magnify glass lens works great for this application.

The focal length of a lens is determined by the radius of it's curvature. In other words, how rounder the lens is. Means the shorter the focal length is and that means. The greater the magnification.

If you have a lens that you don't know what the focal length is. You can find it's focal length by holding the lens in direct sunlight and along side a ruler. Move the lens up or down until the sunlight forms at it's smallest point to the ground. The distance between the lens and the ground id the focal length.

Use cardboard tubing. Diameter depends on diameter of the lens. Cut to 3" length. Cut a slit in the tube all the way across. As shown below and stretch it open. Paint the inside with flat black paint. After dry, insert lens about 1/4" from one end. Use your hands and snug down on the barrel to see if the lens has tight fit. If the lens still loose in the barrel cut the slit wider until you get a snug fit. Remove the lens and paint the rest of the barrel black. Re-insert lens and tightly wrap masking tape around the barrel to hold the lens in place. Make sure to use enough tape to wrap around the barrel, the entire length.

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