For Computer Science Education Week, my school holds a festival with various activities to encourage students to explore robotics, circuits, programming, and making. This year, I was inspired by Fay Shaw to create a station for sewing circuits. I used the laser cutter to cut snowmen, stars and snowflakes out of felt, pre-threaded some needles and created this set of instructions. These instructions assume you know how to thread a needle, begin stitching and tie off.
- Two pieces of felt cut to same pattern (needs area at least 2"x2")
- 1 LilyPad Coin Cell Battery Holder with Switch
- 1 Coin Cell Battery
- 3 LEDs
- Conductive thread
- Non-conductive thread
50 Watt Epilog Helix Laser settings for cutting felt:
- Speed: 75
- Power: 30
- Frequency: 2500
Step 1: Step 1: Sew on Negatives
LEDs have positive and negative sides so it matters how you connect them. Sew each of your negative sides down in the center of your shape using conductive thread. For each hole, you want at least 3 stitches to hold it firmly in place and make sure that the connection is being made. On the back of the fabric then, you'll see your stitches. Try to avoid having any extra thread or loose stitches as these might cause a short circuit later.
After all of the LEDs are sewn on, stitch on the negative terminals of the battery pack with the same thread to guarantee that your negatives are all connected. Put another three stitches in the the first terminal, then sew across with about two stitches to the other terminal and sew it down with three more stitches. BE CAREFUL! Orient the battery pack so that the stitches in the negative terminals will not interfere with stitching the positive ends of the LEDs down. Tie off the thread and cut the ends very short.
Step 2: Step 2: Sew on Positives
Begin stitching the positive ends of your LEDs and battery pack. I started with an LED, then sewed over to the first positive terminal. I continued sewing over to the next LED and then the final LED and the second battery pack terminal. After I finished the second positive terminal on the battery pack, I tied off the conductive thread.
Test your circuit by inserting the battery (positive side facing out) and flipping the switch. If your circuit does not light, try the following:
- change the battery
- check that you do not have any loose threads
- check that your positive and negative threads do not touch or cross anywhere
I've added some comments to the images above to help you understand which stitches are positive and negative. Again, make sure that you are putting three stitches through each hole to make sure they are secure. Do not cross your positive and negative stitches; that would make a short circuit.
Step 3: Step 3: Sew on Top Layer
I used a piece of yarn for a hanger in this example. I think in the future I would actually use a piece of ornament-hanging wire. I sewed through the yarn a couple of times to secure it. Then I stitched around the outside using an overcast stitch because I thought the contrasting color looked nice. You could also just baste or straight stitch them. Enjoy!