A smoke alarm is a device that uses sensors to detect the presence of smoke and then emits an audible alarm. It's a device that uses sensors to detect the presence of smoke and then sends a signal to an alarm system.
Smoke alarms are required by law in most states, so make sure that your place has at least one working alarm. Test it regularly and replace the batteries every year. Smoke detectors can provide an early warning in case of a fire, so make sure to install them immediately!