Door Alarm Sensor (Wired)

int buzzer = 9; 
int red = 13;
int yellow = 12;
int yellowState = LOW;
int REED = 3;
int redState = HIGH;
int proximity = LOW;
int proximityprevious = LOW;


void setup(){
  pinMode(yellow,OUTPUT);
  pinMode(buzzer, OUTPUT); 
  pinMode(red, OUTPUT);
  pinMode(REED, INPUT_PULLUP);
      
  if (yellowState == LOW)       
  tone(buzzer,2500);
  delay(900);
  noTone(buzzer);
  }
 


void loop(){

proximity = digitalRead(REED); 

if (proximityprevious == HIGH)
{
  proximity = HIGH;
}




  
    if (proximity == HIGH)
      
             
   {
              proximityprevious = HIGH;     
              yellowState = LOW;             
             digitalWrite(red, HIGH);
             delay(45);
             digitalWrite(red, LOW);
             delay(5); 
             tone(buzzer, 3000); 
             delay(200);        
             noTone(buzzer);     
             delay(100);       
}
            
    else
             {
              yellowState = HIGH;
             redState = LOW;
             }
                
                
           
   

     
{
digitalWrite(red,redState);
digitalWrite(yellow,yellowState);

  

}
}