interrupteur-tilt.ino
The ball switch closes depending on orientation: perfect for a necklace that reacts when flipped, or a vest that detects a fall. The ball bounces — hence the double read and short delay.
Hardware required
A LilyPad Arduino (ATmega168V/328V, 8 MHz, 3.3 V) with its sew tabs, programmed via an FTDI cable (breakout) and powered by 3.7 V (LiPo) or 5 V on V-REG. 1 ball switch (SW-200D) + conductive thread.
Wiring
One leg to pin 3, the other to GND; the pull-up is internal.
How it works
Each stable change toggles the LED and prints it. When sewing, space the tabs to avoid shorts through the thread. In the Arduino IDE, select « LilyPad Arduino » and the FTDI port, then Upload. Conductive thread adds a few ohms of resistance: keep runs short and insulate crossings.
Going further
Count toggles per minute to estimate activity, or combine with an I2C accelerometer.
interrupteur-tilt.ino
// Switch a bille (tilt) sur la broche 3, LED sur 13.
const int TILT = 3;
const int LED = 13;
bool etat = false;
bool precedent = HIGH;
void setup() {
pinMode(TILT, INPUT_PULLUP);
pinMode(LED, OUTPUT);
Serial.begin(9600);
}
void loop() {
bool lu = digitalRead(TILT);
if (lu != precedent && digitalRead(TILT) == lu) { // petit anti-rebond
etat = !etat;
digitalWrite(LED, etat ? HIGH : LOW);
Serial.println(etat ? F("Incline") : F("A plat"));
}
precedent = lu;
delay(10);
}