Introduction: Rainbow in the Dark: Easy DIY Flashlight Projector

Have you ever wanted to capture a rainbow and bring it into the pitch black? With this quick and easy project, you can do exactly that! This DIY project transforms a standard smartphone flashlight into a vibrant, colorful light display that completely cuts through the darkness.

Whether you want to add a cool, aesthetic vibe to your bedroom decor, create a unique mood light, or just experiment with how light travels through color, this project is the perfect craft. It’s budget-friendly, takes less than 20 minutes to make, and looks absolutely magical when the lights go out.

Let's gather our supplies and get crafting!

Supplies

To build your own rainbow projector, you will need the specific crafting materials and tools shown in the project photos. Gather the following items before starting:

Materials:

1. Clear Plastic Cylinder: A smooth, translucent plastic container that serves as the main body and lens of the projector.
2. Plain White Paper: Used to cut out a clean template strip for wrapping and painting your rainbow design.
3. MonAmi Poster Colors: A set of 12 vibrant jar paints used with a paintbrush to paint the bold rainbow stripes.
4. Assorted Markers:
5. A black permanent marker for drawing guide lines and coloring the dark interior borders.
6. ROYGBIV markers for translucent rainbow projection effect
7. Clear Adhesive Tape: A roll of wide transparent tape to secure the paper template snugly around the cylinder.

Tools:

1. Scissors: A pair of crafting scissors used for cutting the thick plastic container and trimming the paper strip down to size.
2. Long Meter Rule: A wooden or plastic straightedge to measure straight lines on your paper and plastic before cutting.
3. Smartphone Flashlight: Your phone's built-in LED light will serve as the strong light source needed to project the rainbow in a dark room.

The very first phase of the project involves preparing your clear plastic cylinder and sizing up the design canvas. This provides a steady base for the projector and guarantees your hand-drawn rainbow strips align perfectly.

Sub-step A: Cutting and Sizing the Cylinder Base

1. Inspecting the Cylinder: Start with your full-sized, clear plastic container. Ensure it is clean and free of residue so light can pass through easily.
2. Marking the Cut Line: To create a stable base, use your marker to map out a straight, clean slicing guide around the circumference of the cylinder.
3. Trimming the Edges: Carefully cut along your marked line using your crafting scissors.
4. Final Base Check: Once completed, remove the excess plastic trimmings. You will be left with a shortened, perfectly level plastic cylinder ready for your transparent canvas layer.

Sub-step B: Measuring and Applying the Canvas Guide

1. Sizing the Strip: Cut a clean, uniform strip of plain white paper . This strip will act as a structural guide to map out where your clear adhesive tape will be colored.
2. Wrapping the Guide: Wrap the paper strip snugly around your shortened clear cylinder base to measure the exact circumference.
3. Marking the Alignment: Hold the paper firmly against the plastic and use your marker to draw a vertical boundary line across the seam. This marks the exact boundaries of your canvas space where you will apply the clear adhesive tape to draw your ROYGBIV lines!

This step ensures your canvas is perfectly sized and neatly wrapped around the base, giving you a clean surface to structure your projector layers.

Sub-step A: Measuring and Marking the Strip

1. Aligning the Ruler: Lay out your full sheet of plain white paper on the workspace. Align your wooden ruler horizontally across the upper section of the page to establish a perfectly straight guideline.
2. Drawing the Cut Line: Holding the ruler steady with one hand, use your pen to draw a crisp, continuous line across the paper. This line acts as your precise boundary for cutting out a uniform paper canvas strip.

Sub-step B: Cutting out the Canvas Strip

1. Trimming the Paper: Pick up your crafting scissors and carefully cut directly along the straight line you just drew.
2. Inspecting the Final Strip: Once cut, you will have a neat, isolated rectangular paper strip separated from the main sheet, ready to match up with your cylinder base.

Sub-step C: Wrapping and Taping the Base

1. Wrapping the Cylinder: Take your newly cut paper canvas strip and wrap it smoothly around the outer circumference of your darkened cylinder base. Ensure it sits flush with the edges.
2. Preparing the Adhesive Tape: Pull out a small segment of your wide, clear adhesive tape to lock the strip in place.
3. Securing the Seam: Secure the overlapping ends of the paper strip by applying the tape firmly across the seam. Your cylinder base is now beautifully wrapped in its white paper sleeve and ready for the next phase of the project!

With the paper sleeve firmly attached, it is time to build the clear screen or "lens" over the opening of your cylinder. This provides the transparent surface needed to project light.

Sub-step A: Preparing the Transparent Tape Strips

1. Cutting Tape Strips: Pull and cut several uniform lengths of your wide, clear adhesive tape using your crafting scissors.
2. Arranging the Pieces: Lay the clear strips side-by-side flat on your workspace table to keep them clean and easily accessible.

Sub-step B: Layering the Lens Over the Base

1. Placing the First Strips: Take your clear tape strips and stretch them tightly over the open top of your wrapped cylinder base.
2. Trimming the Excess: Carefully slide your scissors around the outer edge of the cylinder to snip away the long, loose ends of the tape extending past the rim.
3. Securing the Overlap: Continue wrapping and layering the clear tape across the top opening to form a taut, clean window. Press down the small remaining edges flat against the white paper sleeve to ensure a tight seal.

This section cries for your creativity.

Detailing of the rainbow lens are the work of your ROYGBIV markers (Red,Orange, Yellow, Green, Blue, Indigo, Violet...).

As shown across the crafting process, the black permanent marker is used to heavily block out the remaining transparent segments of the tape lens so that light is forced to project exclusively through the translucent colored rainbow pattern.

The painting is up to you...

Hmmm...

A job well done for a successful project.