A security alarm is a system designed to detect unauthorized entry into a building or area. It typically includes sensors that monitor doors, windows, and motion within the premises. When triggered, the alarm emits a loud sound to alert occupants and deter intruders. Some systems can also send notifications to security services or the property owner. Modern security alarms may incorporate additional features such as video surveillance and remote monitoring through smartphones. They can be connected to a central monitoring station, which can respond to alerts by contacting law enforcement or emergency services. This enhances the overall safety of the property and its occupants.