The classic light-up LED felt wristband project is a great way for beginners to learn about switches. To turn it on, you connect the ends into a loop that closes the circuit. Traditionally, the fastener is a metal snap connected to the battery and LED with conductive thread. But learning to work with conductive thread can take time, even for those who already know how to sew.
Peel-and-stick conductive fabric tape to the rescue! This no-sew version is quick and kid-friendly. It's also inexpensive enough to do with an entire class, because the battery holder is part of the fabric closure.
Since this project is so simple, you might want to try it with different types of LEDs for different effects. You can even add more than one light to the parallel circuit -- as long as they are all the same kind of LED. I have included directions for standard LEDs (the kind with two long wires, known as leads), Chibitronics Circuit Stickers, and Adafruit Sequins. Here are a few more things to keep in mind:
- If you want to use different color standard LEDs together, give them the "throwie" test first. (A throwie is the simplest kind of LED circuit -- just a light and a battery.) Take the LEDs and slide them over the edge of the coin battery. Make sure the positive lead (usually the longer one) for each LED is on the positive side of the battery (marked with a "+"). If they all light up, you're good. In some color combinations, a few LEDs may look a bit dimmer, but still work. With other combinations, one or more LEDs may not work at all. For the example here, I used flashing LEDs for extra pizzazz.
- Both the Adafruit LED Sequins and the Chibitronics Circuit Stickers have on-board resistors so you can use different colors together. However, you should still test them by placing them on the conductive tape before fastening them down "permanently." (It's not that hard to peel off the tape if needed.)
- Adafruit Sequins can be held onto the project with the peel-and-stick conductive tape, but for added security, use the optional Z-axis tape on the back of each one. (See directions for details.)
For each wristband, you'll need some conductive fabric tape, a 3-volt coin battery like the CR2032, and one or more LEDs (all of the same variety). I also recommend Z-axis conductive tape for holding the battery on when the wristband is open and for attaching Adafruit LED Sequins.
I used felt to make the wristband itself because it's easy to find, cheap, and doesn't fray. To make the wristband thick enough to stay closed, I doubled it with a layer of peel-and-stick felt. (See the directions for details.)
strip of felt about 2 inches wide and long enough to fit loosely around your wrist, adding about 1.5 inch of overlap (generally between 6 and 10 inches long)
strip of peel-and-stick felt the same size
- adhesive dots (non-conductive -- like the kind used in scrapbooking)
- electrical tape
- extra scraps of felt for decoration