The safe

You now have all the know-how to build our safety box!

Let's start with the code:

//Initializing a variable to store the value of the button state 
int lidState = 0; 
int keyState = 0; 
int lidPin = 2; 
int keyPin = 3; 
int alarmPin = 9; 
 
// the setup function runs once when you press reset or power the board 
 
 
void setup() { 
  // initialize digital I/O pins 
  pinMode(lidPin, INPUT); 
  pinMode(keyPin, INPUT); 
  pinMode(alarmPin, OUTPUT); 
} 
 
// the loop function runs over and over again forever 
void loop() { 
 
  lidState = digitalRead(lidPin); 
  if ( lidState == LOW ) 
  { 
    keyState = digitalRead(keyPin); 
    if ( keyState == HIGH ) 
      digitalWrite(alarmPin, LOW); 
    else 
      digitalWrite(alarmPin, HIGH); 
  } 
  else 
    digitalWrite(alarmPin, LOW); 
} 

We start by storing the pin numbers in variables...