Room automation light control - programming problem

Projects Programming
13 
boolean doorSwitch;

void setup() {
  pinMode(doorSwitch, INPUT);
}

I wouldn't recommend sending an uninitialized variable to a function that does something based on it's value.

I also would say it's better to avoid mixing the usage of variables for readings/states with pins:

const int myInputPin = 4;

int myInputState;

void setup()
{
  pinMode(myInputPin, INPUT);
}

void loop()
{
  myInputState = digitalRead(myInputPin);
  // Do something with my input
}