Vehicle Security System

A security system is provided for a vehicle having an on-board diagnostic (“OBD”) data link cable and an OBD port. The system includes, a glass break sensor, and an input connector having a power input configured to be coupled to a vehicle battery voltage input of the OBD data link cable and to provide power to the glass break sensor. The glass break sensor is configured to detect a vibration, air pressure, or audio frequency disturbance and to generate an alarm signal when a disturbance is detected. The microprocessor is configured: to use OBD data to monitor whether the vehicle engine is running; to automatically arm the glass break sensor device when the vehicle engine is turned off; to automatically disarm the glass break sensor device when the vehicle engine is on; and to activate an alarm or a camera when in response to the alarm signal.