if(safetyDistance <= 5) { //If distance 5cm or less
    boolean alarmSetOff = true;
    digitalWrite(ledGREEN, LOW); //Turn green LED off
    digitalWrite(ledRED, HIGH);  //Turn red LED on
    digitalWrite(buzzer, HIGH); //Turn buzzer on
    TFTscreen.background(0, 0, 0);  //Clear the screen with a black background
    displayLockScreen();  //Display "use fingerprint to unlock" message
    //Fingerprint sensor
    fps.Open(); //send serial command to initialise FPS
    fps.SetLED(true); //turn on LED so finger can be read
    delay(20);
    fps.SetLED(false);
    delay(20);
    fps.SetLED(true);
    delay(20);
    fps.SetLED(false);
    delay(20);
    fps.SetLED(true);

    digitalWrite(ECHO_PIN, LOW);
  }

  else if(safetyDistance <= 5 && alarmSetOff, true) { //If distance 5cm or less but alarm already set off, LED stays red
    digitalWrite(ledGREEN, LOW); //Turn green LED off
    digitalWrite(ledRED, HIGH);  //Turn red LED on
    }

  else{ //If distance > 5cm
    digitalWrite(ledGREEN, HIGH); //Turn green LED off
    digitalWrite(ledRED, LOW);  //Turn red LED on
  }
}