A smoke alarm, also known as a fire alarm, is an alarm device used to detect and provide early warning in the event of a fire. They are frequently seen in homes, public entertainment venues, offices, warehouses, and other places. Because fires spread rapidly and the time available for firefighting is short and difficult, they usually cause serious loss of life and property. Therefore, early detection of the fire source can greatly improve the effectiveness of firefighting and minimize losses. The Luftmy editor knows that if a smoke alarm equipped with a PM2.5 dust sensor is installed, it can issue an alarm signal at the first moment of a fire and notify relevant personnel to carry out firefighting.

Generally, when a fire occurs, in addition to burning flames, it is usually accompanied by thick smoke. The working principle of a smoke alarm is to detect the concentration of smoke in the air through an internal dust sensor, thereby providing an early warning for fire. The smoke we see in daily life is actually tiny solid particles floating in the air.

These solid particles reflect light. Photoelectric dust sensors utilize this characteristic by using an internal image sensor to detect infrared light reflected by the airflow carrying dust particles from an infrared light-emitting diode (LED), thereby judging the concentration of dust in the air. The higher the concentration, the stronger the reflected light. When the dust sensor in the smoke alarm detects that the concentration exceeds the set value, the circuit generates an alarm signal and activates on-site alarm equipment. For networked devices, wireless communication modules can be used for remote fire distress calls, sending relevant location information to an alarm platform for timely rescue.

Luftmy dust sensors use the principle of optical scattering to detect dust concentration and particle size in the air. An infrared light-emitting diode and a high-sensitivity photoelectric receiving sensor are built into the dust sensor. The light emitted by the infrared LED produces reflected light when it encounters dust. The photoelectric sensor reflects the dust concentration in the air by detecting the intensity of this reflected light, and the sensor directly outputs a PWM signal. The HPD05 infrared PM2.5 sensor module is developed and produced based on this principle. This sensor is suitable for smoke alarms, air purifiers, air conditioners with purification functions, fresh air systems, and air quality detection instruments.