You’ve probably heard of light-emitting diodes, a type of energy-efficient light. While they’re good for practical reasons—say, illuminating a room or a passageway—they can also add a little bling to clothing. To incorporate LEDs into your favorite accessories, you’ll start by creating a basic circuit from a battery, two pieces of wire, and an LED. You’ll then modify this circuit so that you can turn it on and off using fasteners like buttons, zippers, laces, hooks, and buckles. If you’re interested in trying this with a class or camp, check out the related links.
Target grades: 5-12
Content Areas: Engineering and Technology
Activity Type: DIY activity
Time Required: 20-60 minutes
Materials
- One coin battery for each project you want to try
safety note: coin batteries are harmful if swallowed, keep them away from small children - Conductive, non-coated craft wire (silver), 30-guage or smaller
- Sharp scissors or wire cutters
- LEDs in assorted colors
- *optional: needle nose pliers
- *optional: pencil and scrap paper
- *optional: needle and thread
- *optional: button, hook/eye, metal zipper, shoelaces, metal belt buckle, snaps, barrette, or sunglasses.
Prepare Battery Packs, and Make a Practice Circuit
- Cut two four-inch pieces of wire, and coil an inch of each piece into a spiral.
- Tape one spiral to the positive side of the coin battery so that the excess wire sticks out to the side, and put a bend in that part; this is the positive lead. Tape the other coil to the negative side of the battery so that the excess sticks out in the opposite direction from the first, and leave it straight; this is the negative lead. Put another layer of electrician’s tape around the battery so that there is some excess hanging over the edges; this extra tape will be helpful if you decide to sew the battery into a shirt or shoe later on.
- Look closely at the LED and note that there is a long wire (positive lead) and a short wire (negative lead) coming out of the diode. Using your fingers or some pliers, bend each lead into a coil. This will help you connect the LED to the battery leads and sew it into clothing later on.
- Play around with touching each battery lead to an LED lead until you get the LED lit, noting the positive and negative ends of the LED leads and the battery leads. You’ve made a circuit!
Experiment with adding additional LEDs to the circuit, connecting them with more small pieces of wire. You might want to sketch out the circuit variations that work to guide you later, when you adapt your circuit to an accessory or piece of clothing.
How It Works: The Basics of Electronic Circuits
In order for the LED to light up, electrons must be able to flow continuously from the positive lead of the battery, into the positive lead of the LED, out the negative lead of the LED, and back to the negative lead of the battery. This continuous, uninterrupted flow of electrons is called current. LEDs, like batteries, have polarity, which means that there is a specific direction that current must flow through them: it must enter through the positive lead and exit through the negative lead in order for the LED to work.
Circuit diagrams like the one below are used to illustrate a circuit’s different components, or parts, and the direction of its current:
A switch in a circuit is any component that can open or close the circuit loop. You can simulate a switch by connecting and then disconnecting one of the battery leads from one of the LED leads. Switches in circuit diagrams are often represented by a break with a bent line, like this: |
In this activity, you are going to convert fasteners such as buttons or shoelaces into switches in wearable LED circuits. |
Turn Your Buttons, Belts, and Bows Into LED Circuits
Each of the following diagrams illustrates how the same basic circuit can be used to create an LED-lit accessory that can be switched on an off. These circuits are similar to the practice LED circuit you made earlier, except for one thing: the wiring will connect to a fastener—such as a button or shoelaces—which will serve as a switch that turns the LED on and off. (See circuit diagram above.)
Using your wire, tape, battery, and LED, try one of the ideas in the diagrams below, or come up with your own design. Also, check out the troubleshooting tips below. If you make something really cool, e-mail your examples to educate[at]sciencefriday[dot]com or tweet it to us @scifri.
| In this circuit, the end of one wire connects to one lace, and the end of another wire connects to the second lace, creating a switch. The switch is closed when the shoelaces are tied and the wires touch one another. |
| The metal buckle is the switch in this circuit, which will only close if the buckle is tightened the right amount. |
| In these sunglasses, the switch is between one earpiece and the nose piece. When the sunglasses are put on, the wiring on the earpiece and the nose piece touch, closing the circuit. |
| This circuit is closed when a button wired with both leads is inserted into a button hole that has a wire loop sewn inside. |
Troubleshooting Tips:
- Make sure that the only way that electricity can flow through your circuit is through the LED. If there is another connection that skips the LED, the current will take the easiest route, and the LED won’t light. This can happen when a positive lead crosses a negative lead at an unintended point in your circuit and is called a “short circuit.”
- Some LEDs require so much current that they cannot be used in the same circuit as another LED and still light up—there just isn’t enough electricity to go around. Test which LEDs “play nice” by trying them out in your practice circuit before incorporating them into your clothing.
- Use washable markers or chalk to mark the point of contact between the parts of your “switch”—for example, the place where two shoelaces tie (see picture below)—so that you know where to place your wire.
Test your circuit before installing it into your clothing or shoes to make sure that the LED still lights.
When you are sure that everything is working properly, secure your battery by using a needle and thread to sew through the extra tape hanging over the edges of the battery, attaching it to whatever material you’re embellishing.
Interested in learning more about how science is used in fashion? Check out the Science Friday video about testing the quality of textiles below and our interview with some fashion engineers here:
Smarty Pants: Testing the Quality of Textiles
Related Links
The Tinkering Studio: Sewn Circuits and Sewn Circuits Activity Guide
Squishy Circuits (explore circuits with play dough) from University of St. Thomas