How does it work

The detector has an open measure chamber with a light sensitive sensor. With a second LED, small light pulses are sent inside this measure chamber, but not directly to the light sensor. If smoke particles are getting into this measure chamber they reflect the light pulses to the light sensors and an alarm will be activated. Of course, this is all combined with a lot of intelligent electronics to differentiate from dust or cigarette smoke to prevent false alarms. There are also models which have an integrated heat sensor to be even safer from false alarms.