What is installed on the top of the hotel room?

Installed at the top of the hotel room is a smoke alarm.

Smoke detector is actually another name for smoke detector or smoke detector. Smoke detectors can prevent fire by monitoring the concentration of smoke. An ion smoke sensor is used inside. Ion smoke sensor is a kind of sensor with advanced technology and stable and reliable work. It is widely used in various fire alarm systems, and its performance is far superior to that of gas-sensitive resistance fire detectors.

Principle:

The infrared beam of the infrared emission tube is scattered by smoke particles, and the intensity of the scattered light is directly proportional to the smoke concentration, so the intensity of the infrared beam received by the photosensitive tube will change and be converted into an electrical signal, and finally into an alarm signal.

The smoke sensing of the alarm is mainly completed by the optical maze, in which a group of infrared emitting and receiving photocells are installed, and the diagonal angle is 135 degrees. When there is no smoke in the environment, the receiving tube can't receive the infrared light emitted by the infrared emitting tube, and the subsequent sampling circuit has no electric signal change.

When there is smoke in the environment, smoke particles enter the maze to scatter the infrared light emitted by the emission tube, and the intensity of the scattered infrared light has a certain linear relationship with the smoke concentration.

If the subsequent sampling circuit changes, the main control chip built in the alarm will judge these changes to confirm whether there is a fire alarm. Once the fire alarm is confirmed, the alarm will send out a fire alarm signal, the fire indicator (red) will light up, and the buzzer will start the alarm.

Refer to the above? Baidu encyclopedia-smoke alarm