9. Wearables¶

RESEARCH¶

OHM’S LAW¶

V = I × R

Voltage, current, and resistance relationship
Essential for planning circuits, LEDs, heating, sensors

¶

OUTPUTS¶

Visual Outputs¶

LED Types

Through‑hole LEDs (legs)
RGB LEDs
SMD LEDs (3528 is a good size)
Sewable LEDs

Circuits

May need resistors
Powered by microcontroller (limited current)

NeoPixels

Individual LEDs
Strips
Rings
Matrices
Sewable versions
Must connect to microcontroller and code
May require external power (LiPo, wall power)
Capacitor recommended on power line
NeoPixel Code Generator available

Fiber Optics

Light travels through fiber end
Side-emitting fibers glow along the length
Variables:
- LED intensity
- Fiber type
- Connection method

Thermochromic Ink

Changes color when heated
Variables:
- Pigment quantity
- Mixing medium
- Base fabric
- Room temperature

Heating Elements¶

Materials:

Stainless steel thread
Karl Grimm conductive thread
Conductive fabric
Nichrome wire
Flexinol (SMA)

Notes:

Heating requires high power
Often needs external power source
Controlled using a transistor or MOSFET
Conductivity

Visual Inspiration¶

Moving Target — Maggie Orth
Wifi Tapestry — Richard Vijgen
UV pigments

Sound Outputs¶

Fabric / Textile Speakers¶

Principles:

Coils create magnetic field
Coil traces must not touch
Permanent magnets needed (preferably neodymium)
Produces vibration that can move fabric or air

Variables:

Coil tightness
Material stretch (stretch fabric = louder)
Magnet placement
Gap between coil lines
Resistances around ~8Ω (measure with multimeter)

Circuits¶

Arduino + high-load circuit
Adafruit Mono Amp (switching can be tricky)
DFPlayer Mini (SD card; unreliable sometimes)
Bela Boards
Teensy Audio Shield + Mono Amp

Sound Inspiration¶

Folding Frequencies — EJ Tech
The Crying Dress — Kobakant
Sonoflex — Thomas Preindl
Care Processing Unit — Liza Stark

Shape Outputs¶

Shape Memory Alloys (SMA / Flexinol)¶

Metal contracts when heated
Untrained contracts ~10%
Trained contracts ~10% but follows a “memory shape”

Variables:

Embedding material (light fabrics like silk work well)
Diameter (thicker = more power needed)
Length (longer = more resistance)

Construction Options:

Folding
Curling
Smocking / Shibori
Crimp beads for attaching/soldering

Circuit:

Low current
Must consider resistance + recovery time

Shape Inspiration¶

Jie Qi — Input/Output Paper
Flip Dots
Magnetic Hematite beads

Flip Dots¶

Use electromagnets to flip magnetic disks
Must switch polarity (N/S)
Requires H-bridge for automatic polarity switching
High-load circuit

Variables:

Bead size
Magnetic strength
Coil wind count (50+ recommended)
Wire gauge
Coil wrapping method
Securing beads to textile

Inspiration:

Flapping Wing — Kobakant
Textile flip-dot dress — Instructables

Haptics¶

Vibration motors (2–5V)
ERM motors (simple, 3V)
LRA motors (more precise)

Inspiration:

Social Body Lab

Microcontrollers¶

Pin Types¶

Power Pins¶

GND
5V
3.3V

Inputs¶

Analog (variable voltage)
Digital (0/1)

Outputs¶

Digital (HIGH/LOW)
Analog PWM (wave symbol, all A pins on FabriXiao)

FabriXiao + ESP32-S3¶

Solder miocroschip ESP32-S3 onto the FabriXiao board
Make sure you download and use the ESP32-S3 chip to upload code from Arduiono IDE

Max output = 3.3V
Input via USB = 5V
Use MOSFETs for motors, heaters, SMA, speakers

Additional Components¶

Diode (protective)
Transistor / MOSFET (high-load control)

Reference:

Transistor board slides: https://docs.google.com/presentation/d/1Fa3_2coD3oVF_nZsVp6cF2VkEMZ2YRmqsvGIhmeRsCg/edit?usp=sharing
IRF520 MOSFET module (buy version): https://hobbycomponents.com/motor-drivers/661-irf520-mosfet-driver-module

Materials and Tools¶

Tools¶

Arduino
TurtleStitch: https://turtlestitch.org/run

Materials¶

Copperwire
Magnets
LED
FabriXiao
Xiao ESP32-S3
9V battery
Madeira conductive thread
Spring steel (Fjederstål):

https://www.conradelektronik.dk/da/p/fjederstaaltraad-1000-mm-1-0-mm-reely-1-stk-238103.html
SMA / Nitinol wire:

https://www.magerial.com/
Magnetic beads:

https://www.magneticbeads.net/
KOBAKANT resource:

https://www.kobakant.at/KOBA/

Inspiration links¶

Pauline van Dongen — https://www.paulinevandongen.nl/
Clara Daguin — https://www.claradaguin.com/copy-of-starlink
Sander Hagelaar — portfolio
William Darrell kinetic sculptures — Munchies Art Club
Théophile Blanquet — kinetic textiles
MIT Fiberobo — https://www.media.mit.edu/projects/fiberobo/overview/
Kinetic sculpture video — https://www.youtube.com/watch?v=ROP45rjvOHg
Irene Posch — Embroidered Computer
Flip-Dot Dress — https://www.instructables.com/Flip-Dot-an-interactive-kinetic-wearable/

MOSFET circuit¶

A MOSFET is an electronic switch that allows a microcontroller, which can only output a small amount of power, to control devices that require much more power, such as motors, heating elements, SMA wire, fabric speakers, or electromagnets.

The microcontroller sends only a small control signal, and the MOSFET handles the larger current from a separate power source.

The Three Pins (Channels) of a MOSFET¶

1. Gate (G)¶

The Gate is the control input.

A small voltage from the microcontroller tells the MOSFET when to turn on.

When the Gate receives a HIGH signal, the MOSFET opens and allows current to flow.

2. Drain (D)¶

The Drain is where the higher-power electricity enters the MOSFET from the load.

Think of the Drain as the “input side” for the main current.

3. Source (S)¶

The Source is where the current exits the MOSFET and returns to ground.

It is the “output side” of the main current path.

How a MOSFET Works¶

When the microcontroller sends a signal to the Gate:

The MOSFET opens the connection between Drain and Source
Current flows through the load (motor, heater, SMA wire, etc.)
The device turns on

When the Gate signal is LOW:

The connection closes
No current flows
The device turns off

The Gate requires only a small amount of energy, allowing the microcontroller to safely control a much larger electrical load.

“On/Off” Flip Dot (One Direction Only)¶

Dot moves when the coil turns on, and relaxes when it turns off.

What this does¶

Coil OFF → dot is in its “rest” position
Coil ON → dot is pulled toward or away from the coil
It does not fully flip between two stable sides, it just moves one way

Materials¶

Magnetic bead (e.g. hematite(stone) bead or any small permanent magnet)
Coded copper wire (for the coil)
Power source (battery or supply 9V)
Switch or transistor/MOSFET + microcontroller pin
Some structure to hold bead and coil (fabric, cardboard, etc.)

Step-by-step¶

Make the coil
- Wrap copper wire tightly around a cylinder shape in desired size.
- Aim for at least 50 turns.
- Leave two wire ends free to connect.
Mount the bead
- Place the magnetic bead close to the front of the coil.
- It should be able to move or “flip” a bit, not be glued totally stiff.
- You can hang it on a small thread or pin so it can rotate.
Connect the circuit (simple version)
- Connect one end of the coil to the positive side of your power source.
- Connect the other end of the coil to:
  - a switch that goes to ground, or
  - a MOSFET that goes to ground and is controlled by a microcontroller pin.
Turn it on and off
- When the switch/MOSFET is OFF → no current → coil has no magnetic field → bead sits in rest position.
- When the switch/MOSFET is ON → current flows → coil becomes an electromagnet → bead is pulled toward the coil.

Circuit setup¶

Code for On/Off dots(Blink LED)¶

ls /dev/cu.*

//int ledPin = 5; //actually 4

//void setup() { // put your setup code here, to run once: //pinMode(ledPin, OUTPUT); }

//void loop() { // put your main code here, to run repeatedly: digitalWrite(ledPin, HIGH); delay(1000); digitalWrite(ledPin, LOW); delay(100); }

Examples of flip dot applications¶

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Fabric Speaker¶

A fabric speaker is a speaker made out of textile instead of a hard plastic cone.

Instead of a normal speaker, you sew or print a coil of conductive thread or wire onto fabric and place a magnet nearby.

When sound (an audio signal) is sent through the coil, it creates a changing magnetic field.

This pushes and pulls against the magnet and makes the fabric vibrate.

Those vibrations are what we hear as sound.

Step-by-step¶

You sew a flat spiral coil of conductive thread on fabric.
You place a strong magnet (neodymium) close to that coil.
You send an audio signal through the coil from an amplifier.
The changing current in the coil makes a changing magnetic field.
The fabric moves slightly back and forth and creates sound.

Example code¶

https://docs.arduino.cc/language-reference/en/functions/advanced-io/tone/

define BUZZER_PIN D0 // Example pin

void setup() { pinMode(BUZZER_PIN, OUTPUT); }

void loop() { tone(BUZZER_PIN, 1000, 1000); // 1 kHz tone delay(1000); }

Materials¶

Fabric (non-fraying, slightly stretchy can work well)
Conductive thread or thin insulated wire
Strong magnet (neodymium disk or block)
Audio amplifier (for example, small mono amp)
Audio source (DFPlayer, phone + amp, microcontroller with sound circuit)
Optional: embroidery machine or hand sewing tools

Sensor with coils/flip dots¶

1. Fabric Coil

I stitched a flat spiral coil using coded copper wire.
This coil works as an electromagnet when powered, but in this case I wanted to use it as the sensor in my setup.

2. Flip Dots

Using the coded copper wire I made 3 small coils from the same wire so the were connected.
I placed a small magnet taped to the table under each of the coils.
When the magnetic field changes.

3. Sensor Input

The sensor(fabric speaker before) was connected to the microcontroller.
The sensor triggers the system when it is touch using the sensor code.

4. Microcontroller

Reads the sensor value.
Sends a small control signal to the MOSFET.

5. MOSFET Circuit

Acts as a safe power switch.
Lets the microcontroller control a larger current needed for the coil.

6. Activation

When the sensor is triggered, the microcontroller turns the MOSFET ON.
The MOSFET lets power flow through the fabric coil.
The coil becomes an electromagnet and the copper coils lift up.

7. Flip Dot Movement

The magnetic field from the coil pulls or lifts them in relation to the magnets.
When the MOSFET turns OFF, the coil deactivates and the bead returns or settles in a new position.

Sensor code¶

// Define touch pin and threshold define TOUCH_PIN A3 // Connect your touch sensor to this pin int outputPin = 5; // Output: actually connect to pin 4 define TOUCH_THRESHOLD 100000 // Adjust based on your setup: open the serial monitor and see what values it records

void setup() { Serial.begin(115200); pinMode(outputPin, OUTPUT); }

void loop() { int touchValue = touchRead(TOUCH_PIN); Serial.println(touchValue);

if (touchValue < TOUCH_THRESHOLD) { digitalWrite(outputPin, HIGH); // Touch detected (heater/coil /etc) //tone(outputPin,400,400); //uncomment this for speaker } else { digitalWrite(outputPin, LOW); // No touch //noTone(); //uncomment this for speaker }

delay(100); }

Example¶

Turtle stitch¶

TurtleStitch is a browser-based tool that lets you use block-coding to generate embroidery designs. You create patterns in code, then export them for machine embroidery or textile production. It combines creative design, programming and textiles into one platform. turtlestitch.org+1

Website:

https://www.turtlestitch.org turtlestitch.org