Making a Motion-Reactive LilyPad Patch

Sew a patch that lights up when it moves. A LilyPad accelerometer senses motion in three directions, and a short program flashes an LED whenever you shake or swing it — a reactive costume piece, a dance accessory, or a 'don't-touch' bag alarm. Introduces the accelerometer and reading three sensor axes at once.

中级

1-2 hours

说明

Sew the board, accelerometer and LED

Sew a LilyPad Arduino, a LilyPad accelerometer and a LilyPad LED onto felt. Wire it: the accelerometer's + to the board's +, its - to -, and its X, Y and Z tabs to analog pins A2, A3 and A4; the LED to pin 5 and to -. Keep every line separate.

此步骤所需材料：

LilyPad Arduino Simple Board1 个

LilyPad Accelerometer ADXL3351 个

LilyPad LED - 5 pcs1 包

Conductive Thread - 60g (Stainless Steel)1 轴

Hand Sewing Needles (Assorted, 30-Pack)1 包

Wool Felt Sheet1 张

Connect the programmer

Plug the LilyPad FTDI onto the programming header and connect the USB cable. Open the Arduino IDE and select the LilyPad Arduino board and its serial port.

此步骤所需材料：

LilyPad FTDI Basic Breakout - 5V1 个

SparkFun Cerberus USB Cable - 1.8 meter1 个

所需工具：

Computer with Arduino IDE

Upload the motion sketch

Paste this sketch and upload. It watches how much the three axes change between readings and lights the LED when the patch moves.

lilypad_motion_reactive.inoarduino

// LED lights up when the patch is moved or shaken.
// Accelerometer X/Y/Z on A2/A3/A4, LED on pin 5.

const int LED_PIN = 5;
const int X_PIN = A2;
const int Y_PIN = A3;
const int Z_PIN = A4;

int lastX, lastY, lastZ;
int moveThreshold = 60;   // raise to need a bigger shake, lower for a light touch

void setup() {
  pinMode(LED_PIN, OUTPUT);
  lastX = analogRead(X_PIN);
  lastY = analogRead(Y_PIN);
  lastZ = analogRead(Z_PIN);
}

void loop() {
  int x = analogRead(X_PIN);
  int y = analogRead(Y_PIN);
  int z = analogRead(Z_PIN);

  // total change since the last reading = how much it moved
  int movement = abs(x - lastX) + abs(y - lastY) + abs(z - lastZ);

  if (movement > moveThreshold) {
    digitalWrite(LED_PIN, HIGH);   // moving -> light on
  } else {
    digitalWrite(LED_PIN, LOW);
  }

  lastX = x; lastY = y; lastZ = z;
  delay(50);
}

Test and tune the sensitivity

Hold the patch still — the LED stays off. Shake or swing it — the LED lights. If it's too twitchy or not sensitive enough, change moveThreshold in the sketch (higher = needs a bigger movement) and re-upload.

Go wireless and wear it

Unplug the FTDI, sew a LilyPad coin-cell holder to the board (+ to +, - to -), drop in a CR2032 and switch on. Sew the felt onto a sleeve, shoe or bag — it flashes whenever you move.

此步骤所需材料：