Courtesy of Jason Martineau
CHAPTER 4
Fiber-Optic Fabric Scarf
MAKE AN ETHEREAL GLOWING LIGHT-UP SCARF USING FIBER-OPTIC FABRIC AND A SUPER-BRIGHT LED. This project looks great in low-light situations, such as outdoors at night or in dark indoor locations.
What You Will Learn
In this chapter, you will learn how to
Work with fiber-optic fabric
Add a light source using a simple electric circuit
Sew bias tape on a raw fabric edge
Files You Will Need
Laser cutter–ready scarf pattern: scarfLong.svg and scarfShort.svg
3D model: ledBatteryHolder.stl
Tools You Will Need
3D printer
Sharp fabric scissors
Laser cutter or hobby knife
Sewing machine, thread, and sewing tools
Materials You Will Need
1½ to 2 yards of fabric that can be cut with a laser cutter: cottons, cotton-poly blends, tightly woven linens or silks, wool felt, and natural or synthetic velvets. Do not use fabrics with polyvinyl chloride (PVC), including vinyl and some synthetic leathers, which can release toxic fumes.
4 yards of double-fold or extra wide double-fold bias tape
Fiber-optic panel/fabric (www.sparkfun.com/products/12712)
Black electrical tape
5-millimeter super-bright light-emitting diodes (LEDs; www.sparkfun.com/products/531): white, green, and red recommended
2 coin-cell 3-volt (V) batteries
Opaque 3D printer filament or printed 3D battery holder
No-Laser Option
This project can be made without the laser-cut fabric by replacing it with purchased fabric with large holes or a chunky lace such as guipure lace.
Figure 4.1 Materials for the fiber-optic scarf.
An optical fiber is a strand of glass or plastic designed to carry light from one end to the other through internal reflection. Fiber-optic fabric has strands of plastic optical fiber woven as the warp so that the length of the fabric lights up. The optical fibers were sanded and nicked along their length so that light leaks out of the length of the fibers for a sparkly effect.
In the fiber-optic fabric we use, purchased through Sparkfun, the optical fibers have been gathered into a bundle similar to the size of a basic LED. Holding a powered LED up to the bundle will light the entire fabric.
To see how it works, you can light up the fiber-optic fabric using a basic LED and a coin-cell battery. Because a 3-volt (V) coin-cell battery can’t source enough current to damage the LED, we can connect the LED directly to the battery. Slide a 3-volt (V) coin-cell battery between the legs of the LED with the long leg (1) on the top of the battery (1) where the writing is located and the short leg on the bottom. Pinching the legs should light up the LED. Place the top of the LED up against the bundled end of the fabric, and the fabric should light up. Remember that it works best in low light (Figure 4.2).
Figure 4.2 Fiber-optic fabric lit by holding an LED to the bundled end of fibers.
We’ll prepare the fiber-optic fabric, create a simple light source, laser cut the scarf pattern, and put it all together.
Step 1: Laser Cut the Fabric for the Scarf
1. Download the laser files for the fiber-optic scarf. The file sizes are set for a laser bed size of 18 inches by 24 inches. Depending on the bed size of your laser cutter, you may need to resize these files in a CAD program such as Inkscape or Adobe Illustrator. Each fabric panel is 40 × 75 centimeters (approximately 16 × 30 inches).
2. Cut four scarf pieces and two connector pieces of the fabric with the laser cutter. These will be enough for the front and back of the scarf.
Step 2: Split the Fiber-Optic Panel
Our panel is 40 × 75 centimeters, or about 16 inches wide by 30 inches long. If your panel has different dimensions, adjust the project accordingly. The panel is a little short for a scarf, so we’ll cut it into two narrow pieces to make a longer scarf. Since optical fibers reflect light internally down their length, cutting across the fibers would disable or cut off the light. In order to make two useful pieces, we will cut lengthwise between the optical fibers.
1. Measure along the 40-centimeter width of the fabric, and at 20 centimeters, draw a chalk or pencil line up the 75 centimeters in length of the fiber-optic panel toward where the strands are bundled.
2. Sew two parallel lines of zigzag stitching along the length on either side of the line. These stitches will help to keep your fiber-optic panel fabric from unraveling. Remember to backtack at the beginning and ends of your stitching (Figure 4.3).
Figure 4.3 Sew parallel lines of zigzag stitching along the center length of the fiber-optic panel.
3. Cut along the chalk or pencil line, trying to cut as few fiber-optic fibers as possible. As you approach the bundle of fibers, you will need to carefully separate the fibers to avoid cutting them. At the top, above the fiber-optic panel, continue to cut the fabric. You will have to carefully cut above and below the fiber bundle. Leave the bundled fibers at the top intact; just cut the fabric (Figure 4.4).
Figure 4.4 Split the fabric by carefully guiding your scissors between the warp optical fibers of the panel. When you get to the top, just cut the fabric, not the fiber optics.
4. Sew the panel pieces together by hand or machine using a thread color that matches your laser-cut fabric. To create one long scarf piece, you will need to sew the ends of the panel fabric together with the bundle of fiber optics in the center. Overlap the panel pieces approximately 4 inches. Sew the panel fabric together along the overlap using a zigzag stitch, being careful not to hit the fiber-optic bundle with your sewing machine needle. You may have to make a small slit in both tops of the fabric to allow the fiber-optic bundle end to be repositioned so that the fabric lies flat. You can also sew this together by hand with a running stitch (Figure 4.5).
Figure 4.5 Overlap the ends of the fiber-optic panel, and sew along the overlap to make one long scarf.
Step 3: Sew the Scarf Fabric and Attach It to the Fiber-Optic Panel
1. Sew three fabric pieces together on the short-width end with a ½-inch seam allowance to make one long piece. Repeat for the other three pieces. Press the seams flat.
2. Place one long fabric piece on each side of the fiber-optic panel with the wrong side of the fabric facing the fiber-optic panel. Pin along the long sides of the scarf. Leave space for the metal fiber-optic bundle holder to stick out of the fabric. We’ll need to attach the LED to this in a later step.
3. Sew along both long sides using a regular machine or running stitch, removing the pins as you sew. If your fabric ends up being too long for the fiber-optic panel, you can trim the end of the fabric using scissors. If the long ends are uneven, trim the fabric so that there is an even edge on each side of the scarf (Figure 4.6).
Figure 4.6 Sew the fiber-optic panel to both sides of the cover fabric along the long edges, and then trim to even out the fabric.
4. You can leave the scarf fabric as is, or you can apply bias tape to enclose the long edges of the scarf for a more finished appearance. With any bias tape, the back side of the tape is slightly wider than the front, so when you stitch the tape on from the front, it will be easier to catch the wider edge on the back side of the project.
5. Measure a piece of bias tape that matches the long side of your scarf plus 1 inch for folding the ends under. Cut two pieces this length.
6. Completely open up the three folds of the bias tape fold to find the wider side of the tape. Fold the end you cut of the bias tape in ½ inch so that you have a nice folded edge at the bottom of the scarf. With the tape open, pin the wide side of the tape to the back side of the project, aligning the raw edges (Figure 4.7).
Figure 4.7 Fold the bias tape end over at the bottom for a neat start, and pin the wide side of the tape to the back side, aligning the raw edges.
7. Stitch along the folded crease of the tape, removing pins as you go. Be sure to backtack at the beginning and end of the stitching.
8. Place the project face up on the work surface. Wrap the bias tape up and over the raw edge of the fabric, and secure it with pins. The edge of the bias tape should just cover the line of stitching from the preceding step. The tape should lie flat along the fabric edge (Figure 4.8).
Figure 4.8 Wrap the bias tape over the edges of the fabric so that it just covers the line of stitching.
9. Stitch as closely as possibly to the front edge of the bias tape, removing the pins as you stitch and backtacking at the beginning and end of the stitching. Your stitching should catch the back side of the bias tape to completely encase the edges of the scarf (Figure 4.9).
Figure 4.9 Topstitch the edge of the bias tape to completely encase the edges of the scarf.
Step 4: 3D Print the Battery and LED Holder
Print the case that holds the fiber-optic bundle, LED, and battery. Printing with an opaque filament will block light from leaking out of the LED connection (Figure 4.10).
Figure 4.10 3D-printed battery holder with a lit LED and coin-cell battery.
1. Download the 3D model of the led battery holder: ledBatteryHolder.stl. 3D print with these print settings: 10 percent infill, no supports, and a brim for build-plate adhesion.
2. The model should be able to print without support if it is standing with the tube at the bottom.
Step 5: Attach the Light Source
The LED and the fiber-optic bundle being about the same width fit in the tube end of the battery holder. Once assembled, they can be held together with electrical tape.
1. Find the metal fiber-optic bundle holder in the center of your scarf. Carefully pull the bundle through the fiber-optic panel and your scarf material. If it doesn’t fit through the holes in the laser-cut material, you may need to cut a small slash with sharp scissors. Pull your sewn scarf to one side so you have full access to the bundle (Figure 4.11).
Figure 4.11 Pull the bundle connector through a hole in the scarf.
2. Insert the LED with the wire leads first through the tube end of the battery holder until the LED does not go any farther. Then insert the metal end of the fiber-optic bundle holder into the tube so that it fits right up to the dome part of the LED. Tightly tape the tube end of the battery holder and the fiber bundle with electrical tape so that they don’t come apart (Figure 4.12).
Figure 4.12 Tightly tape the fiber-optic bundle to the LED in the battery holder with electrical tape.
3. Place a battery between the leads of the LED with the positive side of the battery touching the long LED leg. The holder should keep the battery in place through tension.
4. Whipstitch the battery holder to the outer fabric through the sewing holes on the sides. You can tuck the LED and battery inside the outer fabric before you sew on the battery holder, but be aware that this will make it harder to access the battery.
5. This project does not have an on/off switch. As long as the battery is held correctly between the legs of the LED, the scarf will illuminate. To turn the scarf off remove the battery from the holder.
Going Further
This project introduces a simple circuit that lights up an LED when it is in contact with a battery. A next step for this project would be to add a switch to the circuit so that you can turn the scarf on and off without having to take out the battery. The circuit can be connected with wire or with conductive thread. Take this project further by adding a simple light sensor, such as a photoresistor or photocell, that can detect light so that the scarf only lights up in the dark.