A door security system and method may increase the home security for elderly people without limiting the privacy of or convenience for residents. The method comprises detecting closing of a door; keeping a first locking mechanism of said door in an open position for a first predetermined period of time after said closing; after said predetermined period of time, changing said first locking mechanism into a locked position. The re-entry time frame permits a user to re-enter without a key, immediately after realizing they forgot it. The method may further comprise recognizing motion of a person on a door of a house through a camera provided in or near the door; producing streaming footage; sending the streaming footage to a central processing server; processing the streaming footage for face recognition purpose and checking against several; and storing all data on the server.