5. E- textiles

Objectives

-References and Concept development

-Understand how we can produce soft circuits, sensors and actuators

-Learn how to embed electronics on fabrics

-Study and learn soft-hard connections

-Discover necessary materials, components, tools

-Explore and replicate existing projects

Research and Ideation

I find e-textiles both intriguing and captivating, though initially, they felt quite distant from my experience. I began this assignment with no prior knowledge of electronics, as it was something completely new to me. I had never studied it, neither in high school nor at university, so I started by learning its components and the basics. I won't deny that even a small error can prevent a prototype from functioning properly, so patience and persistence are key to achieving successful results.

Benefits of E-textiles

Electronic textiles or e-textiles are a newly emerging interdisciplinary field of research together specialists in information technology, microsystems, materials and textiles. e-textiles offers the following advantages:

-Flexible.

-No disturbing cables in the area.

-Large sensor area.

-Invisible to others.

-Cheap manufacturing.

Sensors

The Digital type works with with switches, these represent a break in a circuit and there are types of switches:

Momentary: best known as push buttons. They stay open as long as you hold the two pieces of conductive fabric sandwoched between a piece of foam, which will have small cutouts where the two pieces can touch. Toggle: Two pieces of conductive material that stay together. They are open in one position and closed in other. (snaps and zippers). Tilt: A conductive bead or pompon makes contact with conductive fabric patches based on its position. Stroke: Close the circuit by pressing conductive materials into contact.

The Analog type works with sensors (also variable resistors), they use resistance to get a broader. range of values. More currrent will allow to change the brightness of an LED, frequency of sound, or the speed or a motor. Resistance can be changed in 3 ways: Distance, resistance increases over distance, 4/5 ohms, limit is 2 ft Contact: some materials are pressure sensitive, will decrease in resistance when pressure is applied to them, so it means it will allow more electrical energy through. Surface area: increasing the size of the area for electricity to flow will decrease the resistance.

These are a few materials you can use if you want to design an analog sensor: 1. Velostat, which is non stretchy 1. EeonTex, resists between 10 OHMS to 10,000 ohms 1. Polysense, best for pressure sensors.

Pressure: Use this to track pressure or weight on an interface or object. Bend: Decreases when bent and more contact is made better for measuring joint movement. Is better if you use conductive thread and not conductive fabric. Potentiometer: Adjust resistance by connecting conductive and resistive material through a wiper (electrical contact which moves across a surface) at different pointsin the circuit. The further away, the more resistance. Stretch: The more a resistive material is stretched, the more its resistance will decrease because it has more surface area to cover. Accelerometic: The weight at the end pulls and stretches the crochet or knitted structure as it gets accelerated.

Digital sensor

Any electronic sensor in which the output gives an OPEN or CLOSE state. A switch is a digital sensor that gives an Off(open) or On(close) output. The clasp of a necklace, a safety pin Open open or closed etc can be used as a switch.

MICROCONTROLLER

Microcontrollers play a vital role in e-textiles by acting as the brain of the system, allowing smart fabrics to interact with their environment. They process inputs from sensors embedded in the fabric and control outputs such as LEDs, motors, or displays. With a microcontroller, e-textiles can perform various functions like monitoring body temperature, detecting motion, or lighting up in response to touch. This integration of microcontrollers enables more advanced, interactive, and customizable wearable technology.

Different types of circuit

There are several types of circuits, each designed for specific functions in electrical and electronic systems. Below are the primary types:

1. Series circuit

In a series circuit, components are connected one after another in a single path. The current flows through each component sequentially, and if one component fails, the entire circuit is interrupted.

Characteristics:

The same current flows through all components. The total resistance is the sum of the resistances of individual components. The total voltage is divided among the components.

2. Parallel circuit

In a parallel circuit, components are connected across common points or junctions, creating multiple paths for the current. If one component fails, the rest of the circuit continues to work.

Characteristics:

The voltage across each component is the same. The total current is the sum of the currents through individual components. The total resistance decreases as more branches are added.

Uses of multimeter

A multimeter is an essential tool in e-textiles (also known as electronic textiles or smart fabrics) to test and troubleshoot electrical components embedded in the fabric. Here's how a multimeter is used in e-textiles:

1. Measuring resistance

E-textiles often use conductive threads, fabrics, or inks that can vary in resistance. A multimeter helps measure the resistance of these materials to ensure they provide an appropriate pathway for electricity.

Why: To ensure the conductive paths in the fabric are working correctly and identify any broken or frayed conductive threads. Example: Measuring the resistance of conductive thread connections in a smart glove to ensure the sensors work efficiently.

2. Checking continuity

The continuity function of a multimeter allows you to check if the circuit is complete, meaning that electricity can flow from one point to another without any breaks.

Why: To ensure that the conductive pathways in the fabric are properly connected and there are no open circuits. Example: Checking for breaks or weak connections in the conductive fabric when sewing LEDs or sensors into garments.

3. Testing voltage

E-textiles may include LEDs, sensors, or microcontrollers, which require a certain voltage to function. A multimeter is used to check if the correct voltage is being delivered to these components.

Why: To verify that the power source (e.g., batteries) is delivering the appropriate voltage to the circuits. Example: Measuring the voltage across an LED to ensure it is receiving the proper power to light up when integrated into a wearable.

4. Current measurement

In some cases, it’s important to measure the current flowing through the e-textile components to ensure they are not being overpowered, which could cause damage.

Why: To prevent short circuits or excessive current from damaging components like microcontrollers or sensors. Example: Measuring current flow through a heating element embedded in a smart jacket to ensure it heats up correctly without overheating.

Day 1 experiment

For my first experiment, I embarked on the exciting challenge of building a basic electronic circuit. I decided to keep it simple yet functional by using just three essential components: an LED, a resistor, and a power supply. My goal was to learn the fundamental principles of electronics, such as how current flows through a circuit and how a resistor helps protect the LED from receiving too much power. As I carefully connected the components, I felt a sense of anticipation, waiting to see the LED light up. When the circuit was complete, and the LED illuminated, it was a thrilling moment. This experiment not only boosted my confidence in working with electronics but also sparked a deeper curiosity to explore more complex projects in the future.

Digital experiment

The code displayed in the picture is designed to blink LEDs using an Arduino Nano. It utilizes the digitalWrite() function to turn the LEDs on and off, and the delay() function to control the timing between the on and off states, creating a blinking effect. The Arduino Nano's digital pins are used to control the LEDs, and the pinMode() function is called in the setup to define these pins as outputs. This simple program is a common starting point for beginners working with microcontrollers, allowing them to learn basic programming and hardware interfacing.

For my digital experiment, I used an Arduino Nano to create a simple LED blinking sequence. The goal was to control the timing and intervals of LED flashes using code. By connecting LEDs to specific pins on the Nano and writing a program to set each pin's state to "HIGH" or "LOW" at intervals, I successfully made the LEDs blink in a pattern. This experiment helped me understand the basics of microcontroller programming, including pin configuration, timing with delay() functions, and how to implement loops to repeat actions. It was a foundational project in learning to control physical devices through code.

This video demonstrates the outcome of my digital experiment with the Arduino Nano, showcasing the blinking LED sequence I programmed. After implementing the code, the LEDs flash on and off according to the set intervals, creating a rhythmic blinking pattern. This visual result highlights the successful execution of the code, where each LED responds accurately to the programmed timing. Watching the LEDs blink confirms that the Arduino Nano effectively controls the physical components, bridging coding concepts with tangible results in real-time.

Embedded Vimeo Video

Tutorials

1 Ardunio Built-in Examples Collection of tutorials to learn the basics of Arduino. All code examples are availabletext

2 E-Textiles Fabricademytext

3 Electronics and Sensorstext