How does a smoke detector work?
ABUS smoke detectors use the optical principle. The internal measurement chamber in the smoke detector contains a light diode and a photo element. The light diode regularly sends out flashes of light that do not hit the photo element under normal conditions. If, however, there is any smoke in the chamber, light rays are deflected. They will then land on the photo lens. The photo element connected to the alarm then sounds.
The sensitivity of the alarm must be set with extreme precision to prevent simple dust particles from sounding the alarm, while also ensuring that any smoke caused by a fire will be detected with 100% reliability. Once smoke has been detected, additional measurements are taken to determine if there is still smoke in the chamber before the alarm sounds.