Abstract: An automatic safety gate or security barrier for preventing infant and/or pet from gaining access through passageways. The gate includes a gate member adapted to be mounted to a wall portion and is movable to a closed position to prevent an infant and/or pet from passing through. The locking mechanism of the gate can be deactivated by a human having predefined properties which are measured by at least one sensor of the gate. Deactivating the locking mechanism allows opening of the gate. The gate can also be manually unlocked by means of a handle. In the case of using a motion sensor, the motion sensor range, angle and height can be adjusted in order to accommodate a variety of openings, such as doors, passageways, stairs, etc.