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Rainbow Projector

There is nothing quite like the majesty and splender of a huge vivid rainbow on a bright day after a storm. Unfortunately rainbows seem to be more than a little uncooperative when trying to coax them indoors. All I wanted was nature's splash of multicolored light on the ceiling. But it turned to more difficult than anticipated.

I tried the traditional prism approach but the projected spectrum was way too small. I looked at commercial offerings - the one that seemed to give good results was battery powered and didn't project the spectrum at all but 'faked' a rainbow by projecting individual colored LEDs. I considered purchasing diffraction grating but wasn't sure what I'd get. I read about mirrors in trays of water and splitting open DVD-RW disks and pealing off metallization with packaging tape. But ultimately I ended up with something much simpler... I ended up with this Instructable!

My Rainbow projector is based upon what I had around the house. The main component is a LED PAR (spotlight) bulb and an unused old CD-R disk. I wanted to make the projector smaller, but the physical size was based on the LED lamp which I already had so unless I wanted to spend more on a new lamp I was stuck with something a bit larger than ideal, but still very nice. The projector is about 12-1/2" tall and about 5" square. The on/off switch is hidden inside the ventilation opening at the bottom.

Step 1: Materials and Tools

MATERIALS:

LED 7w PAR replacement (You must use an LED lamp as incandescent would generate too much heat and be a fire hazard. Also, the lamp needs to be the type with a single light source, [you can see one large yellow dot in the center] not the type with multiple LEDs.)

Unused CD-R (Other disk types might work but this did without any modification, except cutting down to size.)

Wood case (Most of the wood I had lying around so don't try to make any sense of it)

2 - 1" x 5" x 12" (0.75"x4.5"x12") pine - Two Side Panels

1 - 1" x 4" x 3-3/4" (0.75"x3.5"x3.75") Pine - Lamp Socket Plate

1 - 1/2" x 6" x 12" (0.5"x5.5"x12") Pine - Front Panel

1 - 1/4" x 6" x 10" (0.25"x5.5"x10") Poplar - Back Access Panel

1 - 1/4" x 6" x 5" (0.25"x5.5"x5") - Top

Electrical

1 - Plastic Single-gang shallow remodel electrical box (the blue box)

1 - Single Pole Switch (your regular run-of-the-mill switch)

1 - Light Socket with lead wires

1 - Wire Nut suitable to joint two 18AWG wires

1 - Household Extension Cord (of the length you would like the cord on the Rainbow Projector)

1 - Wall Switch Plate single-gang. I used an 'end sectional plate' (the kind for custom multi-gang plates) since it was super narrow to fit in my tight space. However, I did have to cut it down; so in hind sight I would just purchase a regular plastic ('won't shatter' nylon) plate so you can cut it down.

Miscellaneous

1 - CD-R unused disk

1 - #6 x 1" pan head phillips screw to mount socket

2 - #6 x 1/2" pan head phillips screw to mount switch box to side panel

4 - #6 x 3/4" flat head phillips brass screws to fasten rear access panel in place

Wood Glue

Black Spray Paint

Stain/Polyurethane finish

Mirrored Acrylic (Optional)

TOOLS:

Saws for cutting wood

Clamps for clamping wood pieces while glue sets

Screwdrivers

Pliers

Aviation Snips (cutting off wings off electrical box, cutting down switch cover, cutting down CD-R)

Wire strippers

Drill Motor/Drill bits

Paint Brush

<p>Thanks! I used this as a project with my 4 year old who is madly into rainbow everything. I did the prep, made sure all the pieces fit and functioned, then worked with him do the painting and assembly. Great project. </p><p>I made a few mods to the plans:</p><p>1) added feet</p><p>2) moved the switch to the side</p><p>3) placed a little post on the wall to glue the CD to so that it was located directly over the brightest spot of the light bulb</p><p>4) used a DVD and peeled away the top layer - this seemed to give a more vivid spectrum than any other variation of CD/DVD etc. I had around.</p><p>5) modified all the wood dimensions to use what I had on hand and probably made the projection opening too big. There's a bit of white light leakage upward that will need a baffle eventually. </p>
<p>I'm so glad you found this helpful. </p><p>Thanks for sharing your modifications and photos!</p>
<p>This is so cool! If you could dim the light this could make the most epic night light! </p>
<p>Great comment. There are dimmer <a rel="nofollow">switches </a>that have the same configuration as a wall switch and I suspect that they could be used instead of the regular wall switch I used. This type of dimmer switch may require a larger electrical box to mount it in, however.</p>
<p>The LED light you use must also be compatible with dimming. Some are and some are not suitable for dimming. They say on the package and usually the lamp.</p>

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