MAKING A LIGHT-UP BRACELET
Join The Great Create with geeky jewelry inspired by the rainbow assortment of plastic heat shrink tubing, wire and LEDs at RadioShack. This light-up bracelet was designed by Wired.com editor Kathy Ceceri, author of “Robotics: Discover the Science and Technology of the Future” and other kids’ science activity books and co-author of “Geek Mom,” coming from Potter Craft in October 2012.
Shopping List
Heat shrink tubing, assorted sizes and colors
Hook-up wire or other electrical wire
Helping hands (optional)
Get to Know Your Tools and Materials
1. Before you can build jewelry, you have to know what your tools and materials can do. The first step is to take some sample lengths of wire and see how they look with different sizes and colors of tubing around them. Take your wire cutters and snip off some pieces of wire about 3-4 inches long. Try making samples with two, three or more strands. Twist them, braid them, or just lay them together.
2. Heat shrink tubing is usually used for bundling separate wires together neatly on electronics projects. But the variety of colors in the NTE Assortment pack (HS-ASST-9) gives you lots of options for jewelry-making. The pieces are all four inches long, and shrink down to half their diameter when heat is applied. Cut some different lengths of tubing and slip them over the test wires to see what different effects you can create.
3. Even though you only have to apply the heat to the shrink tubing for a few seconds to activate it, you might not want to hold it as it gets hot. RadioShack Helping Hands with Magnifier (GCB-695) has two movable arms to hold objects while you work on them. Arrange the alligator clip “hands” so they hold your wire test piece securely. Be sure to open the clips all the way and slide the wire to the back, past the teeth, to avoid nicking the wires’ insulation.
4. The RadioShack Mini Two-Speed Heat Gun (HG-300D) is the perfect tool for shrinking your tubing. Try the lower temperature first; you’ll probably find that a few seconds on “low” will be fine. Be careful not to melt the wire insulation! Depending on the size of the tubing, you may end up with a tight casing that shows the twisted wire inside, or a sliding round tube you can use like a big bead. Take note of the combination of the colors, lengths, and widths that you like, so you can use them in your bracelet.
5. LED light bulbs need very little electricity — usually around 2 or 3 volts — last a long time, and come in a selection of sizes and colors. The RadioShack package of 20 Assorted LEDs (276-1622) gives you four or five different colors, and two bulb sizes. Test out their color and brightness by sliding a 3V coin battery (CR1220 is a good size) between the wires of the LED (also called the leads). LEDs only work when hooked up in the right direction, so make sure that the positive (+) side of the battery is connected to the bulb’s longer lead (the anode) and the negative side connects to the shorter lead (the cathode). For your bracelet, you can use up to six LEDs on one 3V battery.
Make a Strip of LED Lights
1. Take two pieces of the narrowest tubing (1/16th inch). For your first try, you might want to use clear tubing so you can see how it all works. You will be inserting the leads of the LEDs into the tubes, so that the leads of one are in contact with the leads of the next. Make sure all the long leads go in one tube, and all the short leads in the other.
2. To start, take the long lead of the first LED and poke it into one of the tubes, about half an inch from the end. Poke the short lead into the other tube the same way. Slide the LED down so that the leads are inside the tubes, with the tips sticking out.
3. Take the second LED and insert its leads into the tubes the same way, about half an inch away from the first LED. Make sure the long leads are in the same tube, and that both leads from the second LED are touching the leads from the first LED. Test the connection by putting the battery between the leads of the first LED. You can arch the tubes into a curve to help put the leads in contact with each other.
4. Continue inserting the remaining LEDs, testing as you go. When everything is set up and connected, set up the tubing on the helping hands stand or a heat-proof surface so it curves back. This will make it fit your wrist better. Use the heat gun to shrink the tubing to hold the LED leads securely in place. Snip off any excess tubing.
Make a Wire Bracelet Base and Battery Holder
1. Measure two or more pieces of wire long enough to make a circle that fits loosely around your wrist. The circle must be wide enough to slip on and off over your hand without opening it. Add 3 or 4 inches to this length, and cut the wires. This is the base of your bracelet.
2. Attach the LED strip to the bracelet by wrapping the wires around the strip between each LED. Make sure the leads of the first LED are sticking out on top of the wire bracelet. Slide pieces of shrink tubing over the ends of the LED strip to keep it in place, being careful to leave the LED leads exposed. Alternately, you can also just set the LED strip on top of the wire circle and secure it with pieces of tubing. Use the heat gun to shrink the tubing in place.
3. To turn the LED lights on and off, make a sliding battery holder. Fit the battery vertically between the wires of the bracelet so it is touching the LED leads. Pinch the leads together if needed to make the bulbs light up. Make sure the battery can slide back between the wires so that it is no longer touching the leads. This is how you will turn the lights off. If needed, adjust the battery and LED leads so the battery can sit flat against your wrist.
4. For the cover of the battery holder, take a piece of shrink tubing wide enough to fit over both battery and wire bracelet. When it shrinks, it should fit snugly over the battery. (I used 3/8 inch tubing for a two-wire bracelet.) Cut off a piece of tubing about twice as long as the diameter of the battery. Slip the shrink tubing onto the bracelet, over the wires and the battery, until the battery is about three-quarters covered. The edge of the battery facing the LEDs should be exposed.
5. Position the battery so that the LED leads are inside the tubing touching the battery and the lights are on. Use the heat gun to shrink the tubing. Be careful not to overheat the battery. The part of the tubing over the battery will be flat, but the rest of the tubing may be round. If you want, let the tubing cool for just a second, and then gently squeeze it so that the rest of the tubing is also flat. Make sure it is not stuck to the wire. Test that the battery holder can slide along the wire bracelet so that the LED lights turn on and off.
6. Finish the bracelet by adding more pieces of heat shrink tubing where needed to hold the wires together and shrinking them into place. To close the wire circle permanently, cut one piece of tubing wide and long enough to fit over a double thickness of the bracelet, leaving a bit of extra space. Slip the tubing onto the bracelet. Then connect the ends of the bracelet by wrapping one end around the other. Bend the ends back with the pliers so that they are secure and flat against the bracelet. Position the tubing over the twisted ends and use the heat gun to shrink it into place. Now, try on your new light-up bracelet!
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