Abstract: A child safety seat sensor system and method. The sensor includes a movable member including a connection bar for connection to a device such as a child safety seat. The movable member moves relative to main plate, which is affixed to a fixed structure such as a vehicle frame. Upon connection of a child safety seat to the connection bar, tension is imparted to the movable member causing relative motion between the movable member and the main plate and an output from the sensor indicating that the seat is attached.