Introduction: Leather ETextile Breadboard Bracelet and Continuity Tester
This is a project to make a leather breadboard bracelet and a continuity tester bracelet using only eTextiles and soft circuits. I wanted to make soft wearable tools with the aim that they could be cool accessories as well as being functional.
This Instructable shows you how to make a leather breadboard bracelet step by step. I have added an extra a page which shows the basic principles of my continuity tester bracelet design. This part of the project was not documented so well, but I have included it as I think there are enough images to experiment making your own.
I have used leather to make my breadboard because I love the material, but if you are not confident using leather you could substitute for any non-fraying sturdy material, or if you are a vegan, you can try it with pleather!
This is a project I intend to work on further and I will link this page to any new instructables I make using these techniques.
Step 1: Materials and Tools
- scraps of leather
- scraps of lycra or other knitted non conductive material
- 1 inch wadding or other dense padding material
- stretch conductive material
- bondaweb, Sewfree fusing, or other sheet bonding material
- snaps (and snap tool)
- sewing machine
- zipper foot for sewing machine (recommended but not essential)
- hole punch
- fabric pen or chalk
- ruler or fabric grader
extra materials (and materials for the continuity tester)
- thermochromic paint (optional)
- conductive thread
- dense foam
- copper conductive rip stop fabric
- thermomorph or sugru
Step 2: Pattern Prep
I made my bracelet patterns with just strips of leather, using the measurements from my wrist. These were quite arbitrary, and could easily have been just strips of leather which are cut to length when on the wrist.
I find it useful to draw out the layout to see how where the items will sit together on the wrist, and how close they will be to each other.
The images above show me testing the dimensions for a little pouch to hold components. I would definitely make something like this in paper first to test the size.
Step 3: Making the Breadboard
Draw a grid for your breadboard on to the back of the leather and make the holes with a hole punch.
Iron some bonding material on to the conductive lycra. I am using conductive lycra as it is a knitted fabric, so easy for the components to pierce the surface. You can use any conductive fabric which you are able to pierce with an LED or jump lead.
Cut the conductive fabric into strips according to the size of the holes in your grid. My strips are 4mm wide as my holes are 5mm apart.
Peel the backing from the conductive lycra strips and arrange over your grid on the back of the leather to make a breadboard layout, making sure they cover the holes completely. Press firmly in place with an iron.
Take another small piece of normal fabric and iron bonding to it. Cut it to the size of the breadboard making sure it covers all the conductive material by at least 5mm all around the edge. Peel the backing and iron this over the whole breadboard to seal in the conductive strips. This is so when you pierce it from the other side the strips do not get pushed off with the pressure from the components piercing the surface.
Turn the breadboard to the right side and you will see the conductive fabric through the holes. Cut around the breadboard leaving at least 1cm seam allowance to attach it to the bracelet. If you are not confident sewing the leather, amde the seam allowance larger as you can always trim it away later. Cut the corners away so they can be folded to create the height of the breadboard.
- I used thermochromic liquid crystal paint on my breadboard. This is optional. Because leather holds heat, I though it would be interesting to use thermochromic paint to see if it builds up heat over time. I also thought it would be good to have a heat indicator on a wearable breadboard in case a circuit overheated!
- This was the first time I had made a breadboard, so I cut two pieces. This was so I could experiment with the size and height, and also so I had a stitch test for the sewing machine as leather doesn't like being stitched more than once as the holes weaken the material.
Step 4: Sewing the Breadboard
Cut the wadding and the felt into squares the same size as the breadboard.
The felt will act as a base to protect your wrist from pins and components, and also to create a stable base for the structure of the breadboard. The wadding is to support the components when you push them into the breadboard.
Stack the felt, wadding and leather, and check the thickness. Wadding peels nicely in layers, so you might have to remove a little to make it the correct height. You want it to be about double the thickness of the folded sides you are going to sew to create the height of the breadboard.
Cut a strip of leather for your wristband. (You can either sew the breadboard directly onto the wristband, or sew it to a scrap of leather and stitch it to the bracelet afterwards)
Compress the wadding down, folding in each corner, and pin the breadboard to the wristband base. Pin all the way around the edge. This can be a little tricky as the wadding is thicker than the breadboard, and needs to be compressed as you pin. It might involve pinning and tweaking all the way round the edge a few times. When you are happy with your pinning you are ready to sew.
Stitch around the edge of the breadboard, making sure you sew it tightly in place to compress the wadding. Trim any excess leather from the edge.
Test your breadboard.
I added snaps to my leather bracelet by folding the leather strip around my wrist and marking the correct points. You could also use velcro.
You might want to use a zipper foot to sew the edge as the wadding is thick and hard to sew over. I have done it with both a normal foot and a zipper foot and find it easier to compress the wadding with a zipper foot. Most sewing machines come with a zipper foot in the drawer but this is not essential.
Step 5: Continuity Tester
Extra wristband experiment:
Once I had made my breadboard I realised it would be really useful to also have a continuity tester on my other wrist. I wanted the indicator on the continuity tester to be interchangeable, so I could use either an LED or a motor.
I hot glued two pins to some conductive thread to make the jump leads and stitched them into leather tubes. To seal the edges and stabilise the pins I used thermomorph.
Next I cut three small pieces of foam and glued two pieces of copper rip-stop fabric between each of them, in the same way you see the metal in a traditional breadboard (i like to take things apart to see how they work). I stitched the other ends of my jump lead conductive threads to the back of these pieces of copper fabric.
Then I cut a piece of leather for the housing, using the same technique as I used for the breadboard (see Step 4), cutting the corners and punching two holes to allow components to fit through the leather and touch the copper. This was laid over the foam and stitched tightly around the edges, directly on to a strip of leather to make the bracelet.
This bracelet also has a small pouch for holding components and a pin cushion.
I made the continuity tester wires quite long for functional purposes so they could reach far enough away from my wrist,. I also measured them to be a good length to be able to wrap three times around my wrist and fit neatly into the pin cushion, so they have the appearance of a leather bracelet