5. E-TEXTILES¶

INSPIRATION¶

*1.CuteCircuit - The Sound Shirt | 2. Rachel Freire - Second Skin | 3. Behnaz Farahi - Bodyscape | 4. Ying Gao - Insertitude | 5. Irene Posch - The embroidered computer*

CuteCircute - The Sound Shirt - translates touch into sound
Rachel Freire - is working across clothing, costume and wearable technology and makes inspiring e-textiles.
Behnaz Farahi - Bodyscape explores how human movement can create art by using an interactive lighting system that reacts to body motion.
Ying Gao - Insertitudes - The garments respond to the viewer’s voice by moving their pins, creating a dynamic, conversation-like exchange that reflects uncertainty and the hyper-reactive nature of contemporary life.
Irene Posch - The embroidered computer - is using historic gold embroidery materials and knowledge to craft a programmable 8 bit computer for a table cloth.

CIRCUITS¶

We first set up an easy circuit. Circuits are pushing electrons through materials. Voltage is how strongly the battery pushes the electrons — like a ball sitting on top of a hill that wants to roll down.

Material

Battery (3V)
Battery holder
3 alligator clips
2 LEDs (same color)

Set up 1. Place the battery in the battery holder with + to +. 2. Attach one alligator clip to the positive terminal and the other to the negative terminal. 3. Connect the clips to the LED: the + from the battery to the LED’s positive leg, and the − to the negative leg. 4. If the LED legs touch each other, it creates a short circuit — electricity will not flow. Short circuits produce heat, which is why components can break.

An LED has two legs: the longer leg is positive, and the shorter leg is negative. When viewed from underneath, the negative side of the LED is flat. The positive side of the LED connects to the positive side of the battery.

Series Circuits¶

Putting two LEDs in a row - serial
This setup didn’t work with the 3V battery - You can imagine series circutis like a one-lane road — the electricity gets stuck. The voltage isn’t shared equally between the LEDs, so they can’t light up properly.

Parallel Circuits¶

Putting two parallel circuits which each one having a LED
This setup did work. In a parallel circuit, the voltage is the same for each lamp, which is why it works. You can think of it as a road with two lanes — electricity can flow freely through both paths.

Buildung our own multimeter¶

Choose a fabric and the LED color you want to use.
Twist the LED legs slightly to prepare them for sewing.
Sew one leg of the LED onto the fabric using conductive thread.
Then, sew a line (a path) with conductive thread where the battery will rest.
Make a small fabric cover to hold the battery in place.
Stitch down the battery cover so the thread from above touches the top of the battery, and lead the thread from there to the other leg of the LED.
The circuit should now work — always test the connections as you go.
I added two small hooks at the ends to make it easier to connect with alligator clips

SENSORS¶

Digital Sensors - Switches¶

We had an open circuit that we could close by touching the two alligator clips together. They acted like a switch — when the clips touched, electricity flowed; when they didn’t, it didn’t.

Testing Different Switches

We experimented with several materials to make switches.

I used conductive beads on a thread that could touch each other. When I moved a piece of conductive fabric to connect them, the circuit closed.

Next, I made some loops with conductive thread and another path with the same type of thread. When I bent the loops down to touch the other path, the circuit closed and electricity flowed. Be careful when choosing the thread — not all conductive threads work well enough to carry current.

We used conductive thread — always test it first with a multimeter. A thread showing a low resistance (around 1.8 ohms or less than 50 ohms) is good. If the thread shows 7 megaohms, it’s only suitable for touch sensors, not for regular circuits. The multimeter measures resistance; set it to continuity mode — it will beep when electricity can pass through.

Pressure sensor - Switch¶

Materials:

2 pieces of fabric (thick fabric like wool or scuba dive fabric works best)
2 pieces of conductive fabric or tape
1 piece of Velostat (must be larger than the conductive fabric pieces)

Instructions:

Build a "sandwich" with the following layers: fabric → conductive fabric → Velostat → conductive fabric → fabric.
Cut the pieces as shown in the picture. The Velostat must be larger than the conductive fabric pieces.
Sew each piece of conductive fabric onto one fabric piece.
Leave a strip of conductive tape extending from the edge for connection later, as shown in the picture.
Sew or attach the Velostat onto one of the fabric/conductive fabric layers. It should completely cover the conductive fabric.
Place the second fabric/conductive fabric layer on top.
Sew all the layers together.

Press Button - Switch¶

I want to apply the knowledge I’m gaining in this lecture to costume design, so I decided to make a prototype for a shirt. I simulated the setup on two small rectangles and plan to try scaling it up in the future. My goal was to turn on a light by closing the press button at the center front.

I ironed and folded the center front of both sides, just as I would with an actual garment.
I started with the right side. First, I sewed the female press button onto the fabric. With the same conductive thread, I stitched invisibly to the button underneath and sewed it, connecting both with the conductive thread. Then I checked the connection wit my selfmade multimeter.
On the left side, I did the same, sewing the male press button onto the fabric. Using another piece of conductive fabric, I stitched to the hem, tied off the thread, and placed a small piece of conductive fabric on the knot to ensure conductivity. This is where one side of the battery will be positioned.
I connected the upper press button to an LED and attached the LED using conductive thread. Then I added the connection to the other side of the battery, using a strip of conductive fabric sewn onto the fabric. I folded and secured the hem as I would do in a real garment to test how this technique and the battery could be integrated into actual clothing.
By closing the press button the LED is lighted up. Opening the press button the circuit is interrupted and there is no light.

Potentiometer - Switch¶

I was inspired by this potentiometer I found on Kobakant. For my version, I used scuba dive fabric and made the stitches with a sewing machine. When working with conductive thread, it has to be placed in the bobbin, because the friction in the upper thread is too high and it would break.

The outer circle forms one circuit, and the inner line forms another. Along the inner line, I added a thread with conductive beads. You can move it around in a circle, and when it touches the outer circuit, the connection closes and the LED lights up.

Since I only wanted to test the switch, I tested it using my self-made multimeter and did not connect an additional LED.

Arduino & Sensors¶

Blink¶

We set up the Arduino with an LED and a resistor, connecting them as shown in the sketch below. To check if the Arduino is working, we used the blink test. For this, we followed these steps:

Connected the Arduino Uno to the laptop using a USB cable.
Opened the Arduino IDE and went to File → Examples → Basics → Blink to open the blink sketch.
In the Arduino IDE, selected Tools → Board and chose Arduino Uno.
Made sure the correct port was selected under Tools → Port.
Uploaded the blink function to the Arduino.
Observed the LED blinking to confirm the Arduino is working.
Changed the value of the blink delay in the code to make the LED blink faster or slower and uploaded the changes, playing around with different values to see their effects.

Analog Sensors¶

Pressure Sensor & Arduino - Test¶

We connect the pressure sensor using the red cable for power and the black cable for ground.
The signal cable goes from the sensor’s analog output to one of the Arduino’s analog input pins; we used A0.
After connecting, we open the Arduino IDE and upload an analog input example to read sensor data. We monitor changing numbers in the Serial Monitor based on the pressure applied.
Next, we link the sensor reading to the LED brightness by processing the sensor value with the map() function: outputValue = map(sensorValue, 0, 1023, 0, 255)
Here, 0 and 1023 represent the sensor’s minimum and maximum readings, while 0 and 255 represent the LED’s brightness range (off to full brightness).
If we set outputValue to 255, the LED lights fully regardless of pressure. When setting outputValue back to the mapped value, the LED responds to pressure again.
Initially, the LED might blink constantly. We fix this by adjusting the minimum mapped value—for example, changing it from 0 to 168 makes the LED react only when the sensor is pressed. outputValue = map(sensorValue, 0, 1023, 0, 168)

Sketch for connecting sensor with Arduino

Set up with Arduino

Code with LED minimum value

// These constants won't change. They're used to give names to the pins used:
const int analogInPin = A0;  // Analog input pin that the potentiometer is attached to
const int analogOutPin = 9;  // Analog output pin that the LED is attached to

int sensorValue = 0;  // value read from the pot
int outputValue = 0;  // value output to the PWM (analog out)

void setup() {
  // initialize serial communications at 9600 bps:
  Serial.begin(9600);
}

void loop() {
  // read the analog in value:
  sensorValue = analogRead(analogInPin);
  // map it to the range of the analog out:
  outputValue = map(sensorValue, 0, 1023, 0, 168);
  // change the analog out value:
  analogWrite(analogOutPin, outputValue);

  // print the results to the Serial Monitor:
  Serial.print("sensor = ");
  Serial.print(sensorValue);
  Serial.print("\t output = ");
  Serial.println(outputValue);

  // wait 2 milliseconds before the next loop for the analog-to-digital
  // converter to settle after the last reading:
  delay(2);
}

Pressure Sensor & Arduino - Assignment¶

For the analog switch I first made a sketch to visualise the structure of the circuit. It’s the same mechanism we used with the arduino and pressure sensor before.
I built a circuit for the pressure sensor, and connected 3 LEDs by pushing the sensor the light will be activated.
I connected the arduino and checked the values a explained above. In this case I didn’t have to change any values and the sensor worked well.
Later I coverd the circuit with a fabric and just let the LEDs come out.

CODE: Reading pressure Sensor:

const int analogInPin = A0;  // Analog input pin that the potentiometer is attached to
const int analogOutPin = 9;  // Analog output pin that the LED is attached to

int sensorValue = 0;  // value read from the pot
int outputValue = 0;  // value output to the PWM (analog out)

void setup() {
  // initialize serial communications at 9600 bps:
  Serial.begin(9600);
}

void loop() {
  // read the analog in value:
  sensorValue = analogRead(analogInPin);
  // map it to the range of the analog out:
  outputValue = map(sensorValue, 0, 1023, 0, 255);
  // change the analog out value:
  analogWrite(analogOutPin, outputValue);

  // print the results to the Serial Monitor:
  Serial.print("sensor = ");
  Serial.print(sensorValue);
  Serial.print("\t output = ");
  Serial.println(outputValue);

  // wait 2 milliseconds before the next loop for the analog-to-digital
  // converter to settle after the last reading:
  delay(2);
}