Why are there green lights and red lights in the hotel?

The green light and red light in the hotel are smoke alarms.

1. If the smoke sensor flashes, this is normal. At this time, when the smoke sensor is running, it can sense whether there is smoke and charged particles in the room. If the formed current passes through, it will also flash.

2. The principle is that it has infrared rays. If the infrared beam is scattered by smoke particles, there will be flicker problems. If it is detected that the indoor concentration is relatively large and exceeds the set range, an alarm will be given.