Friends who are familiar with smart homes must be familiar with human body sensing sensors. As the name suggests, human body sensors can recognize the human body in a space. In addition to alerting whether someone has entered the home, they can also cooperate with intelligent devices such as smart switches and appliances to create some good scenes, such as automatically lighting up at night.
At first glance, it may sound good, but some friends who have used it may not think so. Often, customers complain to Mairui that the human body sensor is not working properly and is not sensitive to detection. When people are indoors, the light turns off, and the light turns off halfway through the toilet. So how can we solve these problems? Here, it is necessary to first understand the principle of human body sensors, which scenarios are most suitable for using human body sensors, and how to use human body sensors correctly to achieve accurate recognition.
1、 Principle
At present, the principle of the majority of human body sensors on the market is the pyroelectric effect. The pyroelectric effect refers to some crystals with spontaneous polarization that, when temperature changes, will cause surface polarization charges in a certain direction, that is, potential changes. Infrared has a significant thermal effect, and all objects radiate infrared radiation related to their own temperature, as well as the human body. When this infrared radiation is irradiated on pyroelectric materials, it will cause weak potential changes in the material. By adjusting and amplifying the signal of this potential change, it can be determined whether there is human movement.
From this, it can be seen that the basic function of a human body sensor is to sense the movement of the human body. It must be noted that it does not sense the human body, but rather the movement of the human body, which is determined by its principle.
2、 Usage Scenario
1. Used with lighting fixtures in corridors, bathrooms, balconies, basements, and bedrooms: It can turn on the lights when people come and turn them off when people leave, greatly avoiding waste, saving energy, and saving you the pain of forgetting to turn off the lights. Especially, the human body sensor used in the bedroom can achieve worry free waking up at night, but one thing needs to be noted: firstly, it is necessary to avoid people falling asleep on the bed and unconsciously moving to trigger the human body sensor to turn on the light. Secondly, it is necessary to sense the movement inside the bedroom and not the movement outside the living room, which can often cause the bedroom to be accidentally touched. You can choose to place the human body sensor under the bed and face the inside of the bedroom, using only about half of the sensor sensing area to prevent movement that may be detected outside the living room entrance.
2. Used in conjunction with indoor air conditioning: After falling asleep at night or going out during the day, if you forget to turn off the air conditioning, the indoor human body sensor will automatically recognize all of this and automatically turn off the air conditioning by implementing the set logic.
3. Used for indoor intrusion monitoring and alarm: When there is no one at home, it is clear at a glance whether someone has broken into the house. For this purpose, it is recommended to use it in places where personnel must pass by. At the same time, if there is a pet at home, the human body sensor can be placed upside down to avoid false alarm;
4. In addition to household scenarios, human body sensors can also be used in hotels and guesthouses: replacing existing card insertion and power retrieval, they can also play a role in monitoring room dynamics. People come, automatically turn on the power, people leave, automatically turn off the main switch. Fully humanized. In addition, it can also be used for corridors and garages in schools and residential areas. It can achieve full brightness when people come and half brightness when people walk, while ensuring safety and greatly saving energy.
3、 Precautions for use
1. The installation height should be between 1.2 meters and 2.5 meters. A height below 1.5 meters will reduce the detection range in the horizontal direction, while a height above 2.5 meters will cause the blind spot below the sensor to be too large.
2. If you have a pet cat or dog at home (a constant temperature animal with a temperature similar to humans), in order to avoid its impact, you can appropriately lower the installation height of the human body sensor and install it upside down. Although sacrificing the sensing range, it can prevent accidental triggering caused by pets moving on the ground.
3. Avoid materials such as glass partitions and shower curtains that weaken the transmission of infrared radiation emitted by the human body within the detection range. If there are glass partitions in the bathroom, it is recommended to install the human body sensor above the glass partition, with the detection surface tilted downwards and perpendicular to the plane of the glass partition to minimize the impact.
4. Do not face radiator, fan heater, incandescent lamp and other objects whose temperature may be close to human body temperature.
5. To detect small movements, it is recommended to place the human body sensor as close as possible to the detected human body to improve sensitivity. For example, to detect the human body while using the toilet, a human body sensor can be installed on the back wall of the toilet, with a height equivalent to the height of the head of the person using the toilet (there is usually slight movement of the head during the toilet process), which can continuously detect the human body during the toilet process.
6. If the room is too large and a single human body sensor cannot detect all rooms, multiple human body sensors can be set up to work together; Multiple human sensors can also be used in small spaces to eliminate blind spots and improve detection accuracy.
7. To detect the movement of the human body in certain special situations, the occlusion of other objects can be used to detect the movement of the human body in specific areas or states. For example, in the bedroom, to determine the movement of the human body when getting out of bed, a human body sensor can be installed in the area under the bed, and the obstruction of the bed body can be used to determine the movement of the human body on the ground.
8. In general, the human body sensor in a room should avoid facing the door directly to avoid being triggered by a human body passing by outside the room. Of course, in cases where people need to perform actions such as turning on the light when approaching the door, they can face the door side to detect a human body that is relatively close to the door.
For human body sensors, it is difficult to install them accurately at once, so in daily use, the angle, direction, and position of the human body sensor can be adjusted according to the actual effect to achieve better sensing effect.