Method and apparatus for automatically disarming a security system

A security system configured to monitor at least one door, comprising:

• a system control panel configured to arm and disarm the security system, at least a portion of the security system set to an Armed Stay Mode, the security system comprising at least one Armed Mode and a Disarmed Mode;
• a motion detector configured to detect motion that is within a perimeter around an area to be monitored by the security system and proximate to a door;
• and
• a door sensing unit mounted proximate to the door, the door sensing unit configured to detect open and closed positions of the door, the door sensing unit further configured to send a signal to the system control panel when the motion that is within the perimeter and proximate to the door is detected at substantially the same time as the open position of the door is detected, the system control panel further configured to set the at least a portion of the security system to the Disarmed Mode based on the signal.