Use Sewable Circuits to Make Cool Costumes and Accessories

This project follows the Engineering Design Process. Confirm with your teacher if this is acceptable for your project, and review the steps before you begin.

Refer to the Steps of the Engineering Design Process page for more information about the engineering design process as you do this project. This procedure will guide you through the engineering design process specifically for a sewable circuit project.

1. Define the Problem. Before you start, you need to decide what problem you want to solve with your device. Is your goal to build a decorative light-up costume? To solve a health or environmental problem, like alerting the wearer to too much UV light exposure or poor air quality? This is an open-ended project where you decide what to build, so there are no right or wrong answers to these questions.
2. Do Background Research. Even if you already know what you want to build, you should not just dive right into building it without doing background research first. There are many existing sewable circuit projects out there. The links in the Introduction section and Bibliography are just a few examples. You should do more specific research about the type of device you want to build. Have other people already built similar devices? What parts do they use? How do they work? You should also do research about how to make sewable circuits, so you understand how to sew the parts to fabric and make the circuit connections with conductive thread.
3. Specify requirements. There is still more work to do before you start building something! You need to specify clear requirements for your device. What these requirements are will vary depending on what you plan to build, but here are a few examples:
   1. Wearability: does your device need to comfortably fit on a normal piece of clothing? Will it be a problem if it is too bulky and impedes the wearer's normal movement?
   2. Durability: will somebody be moving around a lot or exercising while wearing your device? Is there a risk of threads getting snagged or parts falling off or bumping against things?
   3. Battery life: it would be kind of sad if your LED costume's lights went out just 10 minutes into a costume party! How long do you need the battery on your device to last?
   4. Sensor input: what does the device need to measure? Does it need to take multiple measurements from different sensors?
   5. Output: does the device need to alert or indicate something to the user? Are there specific requirements for how that must be done, for example, using lights for a hearing-impaired person, or using sound for a vision-impaired person? What about using vibrations?
   6. Budget: do you need to stay under a certain budget for parts?
4. Brainstorm solutions. Once you have specified all of your requirements, it is time to start thinking about ways to build a device that can solve your problem. It is tempting to just go with your first idea, especially if you started this project and already had something in mind that you wanted to build. But, be creative and try to think of alternative solutions. For example, say you planned to put your sewable circuit on a t-shirt. Could your circuit also work on a hat or a glove? Are there different circuit parts (for example, the various different sizes of wearable Arduino boards) that could work? Is there more than one way you could measure the required sensor input or provide output to the user? Try to think of at least a few different solutions and make sketches of them. You may need to make preliminary parts lists for each design, especially if you need to stay under a certain budget, but you do not need to worry about all the details at the brainstorming phase. There are no "bad" ideas at this point.
5. Choose the best solution. Now it is time to look at your brainstormed solutions and evaluate which one will best fulfill all of your requirements. Are there any that you can rule out completely because they will not fulfill one or more of the requirements (for example, going over budget)? If some will fulfill all of the requirements, can you compare them to rank which ones will be better in certain areas, such as more durable or more comfortable?
6. Develop the Solution. Once you have decided on a single design, now it is time to start thinking about details.
   1. You will need detailed sketches of your device. You should make a sketch of the circuit diagram that shows all the parts in your circuit and how they will be connected with conductive thread. It may be easier to make this drawing "flat," even if the physical circuit will wrap around a 3D piece of clothing. You can make a separate sketch showing the physical layout of the parts on the clothing.
   2. You will also need a detailed materials lists so you can purchase parts. Refer back to the materials section for a general overview. You may need to refer to the resources in the Bibliography (for example, to select the appropriate wearable Arduino board), or other specific tutorials like LilyPad Basics: Powering Your Project to decide which parts you need to purchase. If you are doing a programming project, make sure you figure out what type of cable you need to connect to your sewable Arduino, since there are different types of connectors (read the product page for the product you decide to purchase).
   3. For programming projects, you can outline your code using pseudocode or a flowchart. Our How to Use a Button with an Arduino tutorial shows how to design an algorithm using pseudocode and flowcharts.
7. Build a Prototype. Once you have all your parts, it is time to build a prototype. Again, you may need to consult specific tutorials, such as Sewing with Conductive Thread. You may wish to build and test your prototype in stages, for example, by connecting one LED and making sure it works before you connect more LEDs. Our How to Debug a Circuit video is about circuits on a breadboard, but many of the same concepts (like loose connections and short circuits) apply to sewable circuits. For programming projects, you will need to write and upload your code.
8. Test and Redesign. After you have finished your prototype, you need to test it. Depending on how your device will be used, you may wish to test it under "easy" conditions first. For example, you can make sure the entire circuit works before you put the article of clothing on and start moving around, or you can test your project inside before taking it outside. Remember that the engineering design process is iterative. Your device might not work properly or not work at all on the first try, and that is OK! Make careful observations, identify the problem(s), and then go back to the appropriate previous step in the engineering design process. You might just need to repair your prototype or build an improved version of the same device, but it is also OK to change your design or go with a different solution. It is also OK if you need to go through multiple iterations before you arrive at a final prototype.
9. Communicate Results. If you are doing this project for school or a science fair, you may need to write a report, make a display board, or even make a video. Professional engineers do the same thing. They might make technical documentation like computer-aided design (CAD) drawings, circuit diagrams, and well-commented code so other engineers can understand how the device works, or make a less-technical sales pitch or presentation to potential business investors.