A building security management system based on single board computer is currently under development. In this paper, a part of the system which is an automatic door access system using contactless smart card for identification is discussed. Running test shows that the system is working as expected. The system can identify multiple users each with different card. More specific access such as access by day, hour, even minute can be implemented. Alarm is used as indicator if the door is unlocked or any forced intrusion is happening. The corresponding system is going to be integrated in a building security management system to provide safer work environment.