A smoke detector or Head Detector is a device that detects smoke, or heat typically as an indicator of fire. Commercial, industrial, and mass residential devices issue a signal to a fire alarm system, while household detectors, known as smoke alarms, generally issue local audible and/or visual alarm from the detector itself. Most smoke detectors work either by optical detection (photoclectric) or by physical process (ionization), while others use both detection methods to increase sensitivity to smoke.

A smoke detector or Head Detector is a device that detects smoke, or heat typically as an indicator of fire. Commercial, industrial, and mass residential devices issue a signal to a fire alarm system, while household detectors, known as smoke alarms, generally issue local audible and/or visual alarm from the detector itself. Most smoke detectors work either by optical detection (photoclectric) or by physical process (ionization), while others use both detection methods to increase sensitivity to smoke.