9. Wearables

Research

Martina Fendi
Anna Cain
I also really liked the application of light on a wearable scarf as shown on the website of https://learn.sparkfun.com/tutorials/lilypad-safety-scarf#understanding-your-circuit

There wasalso this dress that repells people from coming closer that was very playful.

Tools

• Arduino UNO
• Microbit

Important advice

Short-circuits are very common and it's often the root cause of problems in the circuit :)))

First exercise

During the lecture, we made a circuit that can withhold voltage and release it thanks to a MOSFET:

output : heat pad

This circuit has :
- a MOSFET
- a battery
- Arduino board
- Resistance 100 ohms
- diode
- heating pad

Since the heat was not hot enough to show on the swatches of thermoactive paint, I made a video with a blinking program on Arduino with a green LED.

Swatch #1: arm band for biking

Reference: daydreaming while biking image

Often when I bike, I let my eyes follow the landscape and when it's night time, I might be dangerous on the street. Therefore I made an arm band for biking that lights up when it's dark and says a message when it's light.

Material needed:

- Microbit with light detector and LED screen included
- 3 neopixels
- conductive yarn

1. I embroidered with the machine some conductive yarn on a shell fabric.
2. I hand sewn the neopixels
3. I coded on Microbit

Here is the Javascript reading :

let level = 0
let strip = neopixel.create(DigitalPin.P0, 3, NeoPixelMode.RGB)
basic.forever(function () {
    if (input.lightLevel() == 0) {
        level = input.lightLevel()
        basic.showNumber(level)
        led.plotBarGraph(
        input.lightLevel(),
        255,
        true
        )
        strip.showColor(neopixel.colors(NeoPixelColors.Violet))
        basic.showString("SLOW DOWN")
    } else {
        strip.showColor(neopixel.colors(NeoPixelColors.Black))
        basic.showString("DAY DREAMING")
    }
})

What I really enjoy about the microbit interface is that there is a block reading which makes it more accessible to Newbies like me :)

Swatch #2: rotating hood

I love this precious design from Hussein Chalayan, it's from is AW'07 collection. Such a visonnary.

I tested motors and soft connections. Motors worked with my circuit from the first exercise. I discovered thanks to my classmates Annabel and Claire that long soft connections were not conductive enough for my rotating hood circuit.

Diagram of circuit

PIR VCC → 5V

PIR GND → GND

PIR OUT → Arduino pin 2

Servo signal → Arduino pin 9

Servo VCC → external 5V recommended (or Arduino 5V if servo current is low)

Common ground between Arduino and servo/external supply

Code that includes a servo and a movement sensor

#include <Servo.h>

// --- Configurable pins & timings ---
const int pirPin   = 2;    // PIR sensor output
const int servoPin = 9;    // Servo signal pin (PWM capable)

const int startAngle = 0;    // starting angle
const int endAngle   = 180;  // end angle to move to
const int stepDelay  = 8;    // ms delay between angle steps (smaller -> faster, larger -> smoother)
const int holdAtEnd  = 1500; // how long to hold at 180° (milliseconds)
const int holdAtStart = 300; // how long to hold at 0° after returning (milliseconds)
const unsigned long pirDebounce = 50; // debounce for PIR (ms)

// --- Globals ---
Servo myServo;
int lastPirState = LOW;
unsigned long lastPirChangeTime = 0;
bool motionHandled = false;

void setup() {
  pinMode(pirPin, INPUT);
  myServo.attach(servoPin);
  myServo.write(startAngle);
  delay(500);
  lastPirState = digitalRead(pirPin);
  Serial.begin(9600);
}

void loop() {
  int pirState = digitalRead(pirPin);
  unsigned long now = millis();

  // simple debounce: accept state change only if stable for pirDebounce ms
  if (pirState != lastPirState) {
    if (now - lastPirChangeTime >= pirDebounce) {
      // state changed and remained for debounce interval
      lastPirChangeTime = now;
      lastPirState = pirState;

      if (pirState == HIGH) {
        // rising edge detected
        if (!motionHandled) {
          Serial.println("Motion started — handling event");
          handleMotionEvent();
          motionHandled = true; // prevent re-handling while PIR stays HIGH
        }
      } else {
        // falling edge detected (motion ended) -> reset for next detection
        Serial.println("Motion ended — ready for next event");
        motionHandled = false;
      }
    }
  } else {
    // no state change; update lastPirChangeTime so future changes can be debounced properly
    lastPirChangeTime = now;
  }

  // small idle delay to avoid tight loop
  delay(10);
}

void handleMotionEvent() {
  // Smoothly move from startAngle to endAngle
  if (endAngle >= startAngle) {
    for (int a = startAngle; a <= endAngle; a++) {
      myServo.write(a);
      delay(stepDelay);
    }
  } else {
    for (int a = startAngle; a >= endAngle; a--) {
      myServo.write(a);
      delay(stepDelay);
    }
  }

  delay(holdAtEnd); // hold at end angle

  // Smoothly move back to startAngle
  if (endAngle >= startAngle) {
    for (int a = endAngle; a >= startAngle; a--) {
      myServo.write(a);
      delay(stepDelay);
    }
  } else {
    for (int a = endAngle; a <= startAngle; a++) {
      myServo.write(a);
      delay(stepDelay);
    }
  }

  delay(holdAtStart); // small pause at start
}

video of rotating hood