5. E-textiles

Introduction

This week in Fabricademy focused on e-textiles, exploring new materials and techniques to create soft sensors and textile-based electronics. As a mechatronics engineer and Fab Academy graduate, my background in electronics and digital fabrication gave me a solid foundation, but this week introduced unique challenges with soft materials.

Prior to this week, I was familiar with traditional electronics, but working with textiles required a shift in mindset. Instead of rigid components and wires, I had to think in terms of conductive threads and fabrics, which presented new opportunities and limitations. The hands-on nature of this week was key to understanding how these materials work together in a flexible, wearable context.

For inspiration, I looked at the Snap Circuits product, where modular electronic components can be connected easily. This inspired my project idea: creating modular circuits using soft materials like felt and foam, allowing for easy assembly and reconfiguration of textile-based circuits.

New Materials Introduced

This week I was introduced to new materials like conductive thread, copper fabric, and velostat. Conductive thread allows for flexible wiring, while conductive fabrics, such as copper and silver, can be integrated into circuits. Velostat, with its variable resistance properties, offered interesting possibilities for creating sensors that respond to physical changes like bending or pressure. Combining these materials opened up ways to create useful, functional components.

1. Conductive Thread

• Description: A flexible thread that conducts electricity, functioning like traditional wiring but designed for textile applications.
• Use: It can be sewn into fabrics, making it ideal for creating lightweight, flexible circuits.
• Benefits: Allows for the integration of electronics into textiles without compromising comfort or flexibility.

2. Conductive Fabrics (Copper and Silver-Coated)

• Description: Fabrics coated with conductive metals like copper or silver.
• Use: These fabrics can be used to create large conductive surfaces, touchpads, or soft switches within a textile-based circuit.
• Benefits: The ability to cover broader areas compared to conductive thread, making them suitable for complex, large-scale components while blending into textiles for a seamless design.

3. Velostat

• Description: A resistive material that changes its resistance when bent, compressed, or deformed.
• Use: It can be used as a pressure sensor, bend sensor, or as part of interactive textile designs that respond to touch or movement.
• Benefits: Its ability to respond to physical changes makes it perfect for creating responsive, dynamic components in wearable tech and interactive textiles.

Combining Materials By combining conductive thread, fabrics, and velostat, it is possible to design flexible, functional circuits and sensors. For example, conductive thread could create a sewn circuit, velostat could be integrated as a pressure sensor, and conductive fabrics could serve as larger, flexible conductive areas, resulting in soft, wearable electronics.

Inspiration: Snap Circuits

One of the main inspirations for this week's project comes from Snap Circuits, a modular electronic kit that had a deep connection to my childhood. I vividly remember buying it when I was young, and it became one of my favorite toys. I would spend hours piecing together different circuits, snapping components into place, and watching how various configurations produced different outcomes. It was not just a game for me; it was the spark that ignited my curiosity in electronics.

Playing with Snap Circuits helped me understand the basics of how circuits work, and it became the starting point of my journey in electronics. It was my first experience with modular design, where components could be easily rearranged and reused to create endless possibilities. That hands-on experience, combined with the excitement of seeing my creations come to life, laid the foundation for my passion for electronics and engineering.

This childhood connection directly influenced my project for this week. Inspired by the modular design of Snap Circuits, I aimed to create a similar concept using soft materials like felt and foam. My goal was to develop modular, fabric-based circuits that could be connected and reconfigured, just like the original Snap Circuits, but with a focus on flexibility. The idea of translating that nostalgic experience into a new medium was both exciting and meaningful for me.

Experimenting and Creating a Swatch

To get a feel for the materials and techniques, I decided to start experimenting without a clear plan in mind. I grabbed a piece of jean fabric and began sewing with conductive thread to create a simple trace. This was my first time sewing, so I wanted to practice the stitching while seeing how the thread worked as a conductor.

Next, I bent the legs of an LED and sewed them into place along the conductive thread trace, ensuring that the connection was secure. After that, I continued sewing and attached a snap fitting, which would allow the circuit to be connected and disconnected easily.

For the power supply, I improvised by using copper tape and a bent paper clip to create a basic battery holder, which was an experiment in itself to see how well these materials could work together. I then decided to try making a pressure sensor. Using two small pieces of copper fabric and a piece of velostat in between, I was able to create a simple sensor that changes its resistance when pressed.

The entire process was a hands-on exploration to understand how these materials behave and how they can be combined in a circuit. I wanted to see their conductivity, flexibility, and how well they could be integrated into textiles. This approach helped me get comfortable with sewing and working with these soft materials, giving me insight into how they could be used in more complex projects.

Textile Circuits

Designing the Modules

I began by brainstorming and listing the different modules I wanted to create, including a button, potentiometer, resistor, LED, battery, and jumpers. I decided to standardize the module sizes to either 4x8 cm or 8x8 cm for consistency and ease of connection. With these dimensions in mind, I opened Fusion 360, my current go-to CAD software, and started creating simple sketches. After extruding the designs and adding fillets, I worked on placing components within the modules. Once the design was finalized, I exported it as a DXF file and imported it into Rhino to continue refining the design and prepare for laser cutting.

Design Decisions

For the connection mechanism, I initially tested rivet snap buttons. I wanted to use these instead of sewn snap buttons because they seemed stronger and more secure. However, I encountered issues since I didn’t have the proper tools to set them correctly, so I improvised by using punches available in the lab. After testing the snaps on felt and thin foam, I realized that the weak link was now the fabric itself. To solve this, I decided to double the layers by using both foam and felt. This provided several advantages: the snap button had more material to hold onto, the foam allowed for better laser engraving for labeling the top of the modules, and the felt on the bottom provided a way to hide connections and traces, offering protection from damage.

Laser Cutting and Engraving

I used the laser cutter to precisely cut pieces of felt for the bottoms of the modules and foam for the tops. I also engraved the foam to add symbols or labels to the modules, using different colors to represent different components for visual clarity. The precision of the laser cutting helped ensure the pieces were uniform and consistent across all the modules.

Assembling the Modules

Once all the pieces were cut, I began assembling each module by experimenting with the best configuration of materials. Each module construction involved different components:

• LED Module: Sewed conductive thread to connect the LED to a snap button and used foam to hold it securely.

• Battery Module: Created a battery holder using copper tape and a bent paper clip, with layers of foam and felt for durability.
• Pressure Sensor Module: Used two pieces of copper fabric with a piece of velostat in between to create a functional sensor that responds to pressure.
• Push Button Module: Constructed a soft button using conductive fabric and foam for flexibility.

• Jumper Wires: Used conductive thread and snap buttons to create reconfigurable jumper connections between modules.
• Resistor and Buzzer Modules: Integrated components like resistors and buzzers into foam bases, connected with conductive traces and snap buttons.

This modular system, inspired by Snap Circuits, allows for easy reconfiguration, with the added benefit of using soft materials to create flexible, wearable electronics.

End Result