int Led = 13 ;// define LED Interface
int buttonpin = 7; // define the key switch sensor interface
int val ;// define numeric variables val
void setup ()
{
pinMode (Led, OUTPUT); // define LED as output interface 
pinMode (buttonpin, INPUT); // define the key switch  sensoroutput interface
}
void loop ()
{
val = digitalRead (buttonpin); // digital interface will be assigned a value of 3 to read val
if (val == HIGH)  // When the key switch when the  sensor detects a signal, LED flashes
{
digitalWrite (Led, LOW);
}
else
 
digitalWrite (Led, HIGH);
}


