There is a red flashlight on the roof of the hotel. What is this?

There is a flashing red light on the roof of most hotels. This is a fire extinguishing device called "smoke detector". When there is smoke in the room, the detector will sense it and then analyze the concentration of the smoke. When the concentration reaches a certain value, it will give off a harsh alarm. Some devices will automatically spray water on the round hole to extinguish the fire.

What's that glowing red on the top of the hotel room?

Everyone stayed in a hotel or guesthouse when they went out. It is often found that there is a round plastic object with a diameter of about 10 cm on the ceiling of the room, with a red light flashing on it. Some people may think that this is a camera, but it is not.

Cameras are usually installed in very hidden places, such as under the TV. We just need to keep the room dark, turn on the flashlight of the mobile phone and check around the room to see if there are any abnormal reflection points. In fact, this thing, which is often mistaken for a camera, is called a "smoke detector" and is a fire extinguishing device.

When a fire breaks out, it will be accompanied by a lot of smoke. When smoke enters the smoke detector, it will be sensed. This device will automatically analyze the concentration of smoke. If the concentration exceeds the set value, the device will trigger a fire alarm, and then the small hole next to it will automatically spray water to extinguish the fire.