The Tilt Sensor consists of a 10kΩ resistor and a metallic ball switch with bidirectional conduction that will open/close the circuit depending on its tilt degree. It does not measure tilt angle.

Connect the module's Power line (middle) and ground (-) to +5 and GND respectively. Connect signal (S) to pin 2 on the Arduino.

The following sketch will turn on the LED on pin 13 of the Arduino when the module detects a change in inclination degree. The Tilt to turn the LED on/off.

int tiltPin = 2;      // pin number for tilt switch signal 
int ledPin =  13;     // pin number of LED 
int tiltState = 0;    // variable for reading the tilt switch status

void setup() {  
  pinMode(ledPin, OUTPUT);  // set the LED pin as output      
  pinMode(tiltPin, INPUT);  // set the tilt switch pin as input
}

void loop(){
  // get the tilt switch state
  tiltState = digitalRead(tiltPin);

  // check if tilt switch is tilted.
  if (tiltState == HIGH) {     
    digitalWrite(ledPin, HIGH);  
  } 
  else {
    digitalWrite(ledPin, LOW); 
  }
}