There's a dilemma when you're sewing e-textiles. The thread needs to be conductive, strong, and flexible, and that usually means that it's dull braided or twisted steel. It works, but it's not very attractive. Most people deal with this by hiding the conductive thread somehow, which means the viewer really doesn't get the full effect of the needlework.
But what if you could use threads that were attractive on their own, so you didn't have to hide them? Actually, you can -- you just have to learn a new way of sewing.
Japanese embroidery uses a lot of metallic threads, as you can see from the picture here. These threads are usually thin sheets of metal or mylar wound around a fiber core. Threads like this will shred to pieces if pulled through fabric, so there is a special embroidery technique used for them, called "couching".
This technique also works very well for conductive threads and wires, so you can have your fancy embroidery and your LED's too.
(Photo credit: Bruno Cordioli, via Wikimedia Commons. )
Step 1: Don't Pull It Through, Just Tie It Down.
First, a little background. In this pair of pictures, you can see how Japanese gold embroidery works. The metal thread isn't pulled through the fabric during the sewing. Instead, it's just laid on top of the fabric, and another thread is used to hold it down onto the surface.
The advantage to this technique is that you can use a nice, thin, flexible thread to sew with, and that means you can use stiffer threads that would be miserable to use in a needle. You can even use wire.
Step 2: Materials
Here's what you will need for this technique:
- Conductive thread or thin wire.
Note that this does not need to be the steel conductive thread sold for e-textile work. Many other metallic threads conduct perfectly well. In the first two pictures, I'm testing a gold thread called "French tinsel", which is sold for fly-tying. As you can see, it does a great job as a conductive thread for a sewable LED.
Another useful "thread" for this work is magnet wire. It's got great conductivity, looks nice, and is already insulated, so you don't have to worry about short circuits. Just remember to scrape the enamel insulation off in places where you need an electrical contact.
- "Couching" thread.
You will also need a thread to hold down your conductive thread. This is called the "couching" thread.
If you want the couching to be inconspicuous, like it is in the deer embroidery from the previous step, select a plain sewing thread close in color to the conductive thread (cream or gray, usually).
If you want to make designs that show up against the metal, select an embroidery floss in a contrasting color. I'm using red silk embroidery floss in this Instructable, but lots of different threads would work fine.
- A free-standing frame.
You want to use both hands for this technique: one to hold the needle, and the other to guide your conductive thread where it needs to go. The fabric should also be held tight and flat in all dimensions, so it doesn't pucker.
To make all of this easier, you should consider mounting your fabric in some kind of hands-free frame. A standing embroidery scroll frame is very nice, but you can also use a picture frame, some thumbtacks, and a box to prop the frame against. As long as both hands are free to work, you're good.
Step 3: Sewing
Once you're all set up, attach one side of your conductive thread or wire to your first electronic component. Then, start guiding the conductive thread along the surface of the project with your non-dominant hand.
Every quarter-inch or so, bring the needle with your couching thread up from below the fabric and make a little loop around the conductive thread. Bring the needle back down through the fabric again, very close to where it came up, and pull the loop tight.
You can turn corners and create designs with the metallic thread if you like -- as long as you make enough little loops to hold the thread down securely, it will stay where you put it. Here, I've used needlepoint canvas and silk brocade as the background fabrics, but this technique will work with pretty much any fabric.
Step 4: Embroidered Wire Harnesses
If you're using magnet wire, which has enamel insulation and won't short-circuit if two wires touch, you can try another handy variation on the technique. Several wires can be laid right next to each other (for example, to connect to a bank of LEDs), and you can create little designs on the metal surface using a contrasting-color couching thread.
This is easiest to do on fabrics that have countable threads, such as cross-stitch fabric or needlepoint canvas. In the picture above, I have offset my stitches one thread to the left each row, which creates a little pattern of diagonal lines.
If you want a similar effect with uninsulated metallic thread, you can couch a non-conductive material like perle cotton in between the individual conductive threads to provide a little insulation.
Hope you enjoyed! And don't be afraid to show off your stitches.