Introduction: Wearable Tech Wallet

In my middle school Makerspace class, I am always looking for new projects that can blend practical life skills with tech skills. When I came across this Three Stitch Wallet Instructable by willcase I knew I had the makings of my next project!

Sewing is an important skill for middle school kids to learn and I use this well-designed wallet to anchor a wearable tech project that also teaches basic coding, project design and perseverance. If you want to stitch together sewing and coding, keep reading!

Number of classes: 10-12 (@80 minutes) depending on preexisting coding skills.

Target audience: Middle school or high school Makerspace or Design classes.


Lilypad Lilymini

Conductive thread

Wallet pattern

Heavy canvas, nylon or cordura

Pins and needles

Tailors chalk

Cutting mat

Razor knife/scissors

Sewing Machine

Hot glue gun

Puffpaint for fabric (optional)

GitHub repository for Arduino files (Optional but a great way to deliver code to kids)

Step 1: Learning to Sew

When I start this project, I begin with basic sewing. We learn to sew a button back onto a piece of fabric and then to do a simple running stitch. For many of my students this is the first time they have sewn and I get questions about why they need to learn this? Usually, I point at their shirts and talk about buttons falling off or that someday they might need to quickly hem a pant line.

The process of learning to sew is not complex and there are many great Instructables that can teach you how if you want to know more.

Step 2: Prepping the Wallet

The Three Stitch Wallet Instructable by willcase really does walk you through making the actual wallet in a very clear manner. What I want to discuss is doing it with students.

To begin with, I precut the canvas to 12 x 9 inches (305 x 230 mm). The pattern only needs 11x8.5 inches (Letter paper size) but this gives the students a little extra to cut from. I find it helps. It is also a little more forgiving to me and the need to precut all the fabric for my classes. Willcase indicates that this wallet can be made with just about any sturdy fabric, even Tyvek. I chose a nylon canvas material that is sturdy and will not fold over too easily but is also light enough for a middle schooler to push a needle through repeatedly. I don't know exactly what weight fabric it is, but it is similar to what is used on lightweight backpacks. Probably about 500 denier. It is important that it not be too supple or it will fold over on itself and that could lead to the conductive thread touching and the LEDs shorting out. More on that later.

Before we go on to the coding, I have the students use a razor knife/box cutter/scalpel and good fabric shears to cut the pattern. I pre-print the patterns for the kids as well, so there are no scaling issues. As willcase demonstrates in his instructable, we tape the fabric with the pattern on top to a cutting mat and then carefully cut all the marked parts. Patience and manual dexterity are key here. I will help the students with the card slits when needed, but usually, encourage them to just take their time. Mistakes happen and I just try to minimize them. Extra precut canvas pieces are good to have. I prefer that the students use the scalpel/razor knife as it is easier to follow the pattern on a cutting mat than to use shears while holding a pinned pattern.

Step 3: Learning to Program

As middle school students, almost all of my kids come in with no programming knowledge. Normally, we have spent some time working in Scratch to learn the basics of code blocks and programming, but they don't understand the syntax.

To get started on the Lilymini you will need to work with the stand-alone version of the Arduino IDE. Arduino does not support the Lilymini on its web editor.

In addition to the Arduino IDE you will also need to follow the directions on the Sparkfun Lilymini page to add the compilers for the Lilymini. If you have not used a Lilypad or are not familiar with wearable tech, this guide by Sparkfun, is a good place to start.

I provide all three of these links to my students at the start of the project. This makes it possible for them to continue to work with the Lilymini after the project is done and work on it at home if they want to. The other piece I provide to my class is a link to my github page. This includes examples of simple and more complex code that they can use to get the Lilymini to perform different functions. Github is an easy way to demonstrate code on the Lilymini and then have the students practice making changes to it to see what happens.

This portion of the project can take as long as you need it to. I usually spend a day introducing the Lilymini, the way it works and the most simple example code for making it blink. The Lilymini comes preloaded with three different sequences that demonstrate all the features (buttons, light sensor, RGB and white LEDs).

Once they learn how to push new code to the Lilymini, we talk about the syntax of the Arduino language and discuss the void setup and void loop, the need to use semicolons and curly braces. I am in no way a master coder. I enjoy it and practice with it when I can, but having the prewritten code for them to use helps students feel successful early and gives them code that I am familiar with so that when they break it (which I encourage them to do!) I can usually spot the problem quickly. Coding can seem totally overwhelming to kids (adults too) and I am usually pretty flexible about the time I spend on teaching it. I want to make sure that everyone can at least get all the lights to flash in different sequences and for different amounts of time. The use of the button and light sensor are great and I work with the more advanced kids to integrate them into their designs.

Step 4: Attaching the Lilymini and Lights

After the students have become comfortable with writing and modifying code, we switch back to the physical wallet. In my demonstration piece, pictured here, I cut all four of the card slits from the pattern. As my kids do it, I am having them only cut two, on one of the sides. I found the extra slits make it more difficult to attach the Lilymini and really, what middle school kid has more than two credit cards?

With the pattern cut out, we use a warm (set to nylon) iron to make creases along all the fold lines. This helps to define the wallet visually and also makes sewing with the machine easier. We then pin the wallet up so the kids can see what it will look like.

Using the paper pattern as a test guide, I have students come up with a layout for the lights and the Lilymini. I like to have them come up with a couple of ideas, some that are safe and basic and some that are more daring. As I watch them sew at various times in the project I steer them towards one or the other of those ideas. At this point, one of two things needs to happen based on the LED/Lilymini design the student has come up with. Either they need to attach the Lilymini and some or all of the LED/sensors and then sew the wallet together or they need to sew the wallet together on the sewing machine then attach the Lilymini and LEDs. This depends on the design and light layout. I usually help them decide based on their thinking and ideas.

The most important part of the light layout is that it not have conductive thread lines that touch or overlap. Conductive thread is not insulated and so anytime thread unintentionally touches thread or a contact on the Lilymini or light, a short will happen. Make sure to check their plans several times before they start sewing. This is also why a sturdy fabric is important.

I have found that most students will be more successful if they attach the Lilymini and lights first and then use the sewing machine to bring it all together at the end. For certain patterns, this may not be the best idea.

To attach the Lilymini, use a standard needle and the conductive thread. Sparkfun has good directions on how to attach components to fabric and protect them with puff paint. I usually start by attaching the Lilymini at three points, nice and tight so it doesn't wiggle. Then use hot glue to attach the LEDs, sensor and button as needed. I did notice as we did this that the glue did not hold permanently to the nylon canvas so it might be a good idea to do it piece by piece.

When sewing from the Lilymini to the components, it is important to plan out the path in advance. Make sure the students check regularly, as they sew on new components, for potential shorts. Using tailor's chalk to map the path helps to keep the lines neat and straight. Using the simple running stitch that students practiced at the beginning, have them make nice even stitches from the correct pin on the Lilymini to the LED. I prefer straight lines, as they are easier to keep track of. However, some students may want to be more artistic with curved lines. This is fine, as long as they are aware of the path each line needs to follow. When sewing components remember that the thread goes from the numbered pin on the Lilymini to the positive (+) terminal on the LED. The thread is then tied off and cut and a new line goes from the negative (-) terminal back to the negative (-) terminal on the Lilymini. For ease, all the negative (-) terminals can be sewn on the same thread, if it makes sense. Each positive (+) terminal must be connected independently to a numbered pin on the Lilymini though for it to operate independently. For more info on that see the Sparkfun link. The button does not have a positive or negaitve side and needs to go from a numbered pin to one end and then from the other end to negative. To use the light sensor a number pin, the negative and the positive contact will be required. This means additional planning is required in the layout as the sewing complexity increases.

One of the best steps when adding any components is to wire in a new one then push a simple blinking code to the Lilymini to make sure it is wired correctly before going on to the next component. There is nothing worse than getting a bunch of sewing done only to realize it doesn't work and have to pull stitches. As you add components, increase the complexity of the code to try all the attached parts at the same time. This is also a good way for the students to really understand what their code does. They will actually see it come to life as their project advances.

Step 5: Putting It Together

When your students have finished connecting all their various components, or when it makes the most sense to sew the wallet together, they will need to transition to the sewing machine. Since most kids don't have much or any experience with a sewing machine, this is best done in a one on one situation. Depending on how quickly students are working, this could be easy to do or may require that some kids work on developing more complex code while they wait for time at the sewing machine.

Once again, the directions for sewing the wallet together are explained well by willcase. These directions are to help you when working with students.

Assuming the hard creases that were ironed in earlier are still present, fold in the edges and pin in place. There is a picture of this in Step 2 above. Then use the sewing machine to make the stitch along the bottom of the bill slot side. Be very careful as they sew, that the stainless steel thread is not getting cut or crimped, where it might break, in the process. My suggestion is to test the connections after doing this step. If something is not working it is easier to troubleshoot now than when the wallet is fully finished.

If everything is working fine, fold up the card slot side as per the pattern directions and sew along each edge to finish the wallet. It is a good idea to go over the edges and pressure points a couple times with the sewing machine to reinforce them.

The wallet is done! Students can use puffpaint to reinforce and protect the conductive thread or to make additional designs on the wallet. This is not necessary but can make it possible for their art skills to also be displayed. Have the students make sure their code works as designed and tweak or modify it as needed. This is also a good time to have the more advanced coders create additional sketches that can be pushed out to change the sequences.

To aid in teaching this I have attached my student handout here as a pdf. Feel free to modify it to meet your needs. My assessment for the project involves a demonstration of the working product, the final Arduino sketch being submitted and answers to the reflection questions in complete sentences.

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