5. E-textiles¶

This week is focused on understanding electricity basics on soft and flexible materials.

Theory¶

Analog Sensors:
    Definition: Analog sensors measure continuous, varying signals and output data as a range of values (e.g., voltage or current).
    Output: Continuous signal (e.g., 0 to 5V).
    Example: A temperature sensor that outputs varying voltages corresponding to temperature changes.
    Key Feature: Captures precise, detailed variations but often requires additional processing (e.g., through an analog-to-digital converter) to interface with microcontrollers.

Digital Sensors:
    Definition: Digital sensors measure discrete signals, providing a binary output (e.g., HIGH or LOW, 1 or 0).
    Output: On/Off or a series of digital pulses (encoded data).
    Example: A motion sensor that outputs a HIGH signal when motion is detected and LOW when no motion is detected.
    Key Feature: Simpler to interface with microcontrollers as the signal can be directly read by digital pins.

Here is a technical sheet for making circuit drawings :

Inspiring concepts¶

References & Inspiration¶

My only reference and inspiration is this vodoo doll, playful concept to build analog switch!

There is also my button collection which is conductive. I will undoubtebly use it.

I upcycle waste into different sized buttons

I made sure it was conductive by measuring it:

Tools¶

- Seeed XIAO-RP2040
- [Arduino IDE](http://class.textile-academy.org)
Multimeter

Conductive tape

Batteries

220 resistance x2

Diode x2

Conductive knit

Conductive yarn

Sewing machine (+ regular thread)

Needles

Crocodile clips

Analog soft sensor¶

My sketch for both sensors is :

The battery goes onto the switch, then parallel diodes and back to the battery.

Self made buttons with tin / SWITCH 1¶

Here the idea was to imagine how my button could be used if in a conductive garment. Therefore I used a conductive knit to make the button hole, and a non-conductive fabric to sew my button. Whe it's buttoned, it's conductive.

The tin button is linked by a silver conductive yarn to the circuit.

Voodoo style / SWITCH 2¶

This one is made with conductive fabric on both side of the cushion. I used my project from

The voodoo cushion is linked separetely top and bottom to the circuit. It is in contact only when a needle goes through.

Digital soft sensor¶

My board is the Seeed Studio XIAO RP2040. It looks like this for the connections :

I want the diodes to blink when th circuit is closed therefore the code is the following :

// Pin setup
const int LED1 = D0;
const int LED2 = D1;
const int SWITCH_PIN = D2;

void setup() {
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(SWITCH_PIN, INPUT_PULLUP); // Use internal pull-up
}

void loop() {
  int switchState = digitalRead(SWITCH_PIN);

  if (switchState == LOW) {
    // Circuit closed — blink both LEDs
    digitalWrite(LED1, HIGH);
    digitalWrite(LED2, LOW);
    delay(300);
    digitalWrite(LED1, LOW);
    digitalWrite(LED2, HIGH);
    delay(300);
  } else {
    // Circuit open — turn off LEDs
    digitalWrite(LED1, LOW);
    digitalWrite(LED2, LOW);
  }
}