KY-017 Mercury switch module

//KY017 Mercury open optical module
int Led = 13 ;// define LED Interface
int buttonpin = 3; // define the mercury tilt switch sensor interface
int val ;// define numeric variables val
void setup ()
{
  pinMode (Led, OUTPUT) ;// define LED as output interface
  pinMode (buttonpin, INPUT) ;// define the mercury tilt switch sensor output interface
}
void loop ()
{
  val = digitalRead (buttonpin) ;// read the values assigned to the digital interface 3 val
  if (val == HIGH) // When the mercury tilt switch sensor detects a signal, LED flashes
  {
    digitalWrite (Led, HIGH);
  }
  else
  {
    digitalWrite (Led, LOW);
  }
}