Internet of Things (IoT) Practice Exam 2026 – Comprehensive Prep Resource

A door alarm functions primarily as a sensor because its main role is to detect changes in the environment, specifically unauthorized access or movement. When the door opens or closes, the sensor detects this change, often using mechanisms like magnetic switches or motion detectors.

In the context of the Internet of Things, devices classified as sensors are responsible for gathering data from their surroundings and sending this information to a control system for processing. This capability allows the door alarm to trigger alerts or notifications when it senses an event, thereby enhancing security.

Actuators, on the other hand, are devices that perform actions based on commands from a control system, such as opening or closing a valve or a door. In contrast, the door alarm does not perform physical actions but instead focuses on sensing.

Control devices are systems that manage other devices according to predefined criteria. Since the door alarm does not control other devices but rather collects data, it does not fit this classification.

Overall, identifying the door alarm as a sensor aligns with its primary function in security systems within the IoT ecosystem.