Which of the following is an example of an intrusion detection device?

An example of an intrusion detection device is a glass break detector. This type of device specifically monitors for the sound or vibration associated with breaking glass, which is a common method employed by intruders to gain unauthorized entry. When the glass break detector is triggered, it alerts the security system, potentially notifying the homeowner or relevant authorities of a potential break-in.

While a motion sensor also detects movement and can act as an intrusion detection device, it is often more general in its application and can trigger false alarms based on benign movements, such as pets or passing vehicles. A keypad entry system is primarily used for access control rather than detecting intrusions, as it allows authorized individuals to enter a secured area. Surveillance cameras, while crucial for monitoring and recording events, do not actively detect intrusions but instead provide visual evidence that can be reviewed after the fact.