What do you know about hunman body motion sensors?
Body sensors have only one function - to sense the movement of a person or a pet.
It is worth noting that it senses the movement of the human body and pets, rather than people or pets, which is determined by the principle of the human body sensor itself.
At present, the vast majority of human body sensors in the smart home market are using pyroelectric infrared sensors.
Pyroelectric effect
Due to the change of temperature, pyroelectric crystals and piezoceramics will appear on the structure of the charge center relative displacement, so that their spontaneous polarization strength changes, so as to produce different signs of bound charge at their ends, this phenomenon is called the pyroelectric effect.
To put it simply, the human body or animal body will radiate infrared rays related to its own temperature. When the infrared rays radiated radiated to the pyroelectric material, the pyroelectric material will generate a signal of related potential change. According to this signal, we can judge whether there is a human body or pet moving.
However, because the infrared light emitted by the human body is very weak, most of the human body sensors will add a Fresnel lens that gathers the infrared light of the human body to achieve more accurate detection of human movement.
From the principle point of view, most of the current use of pyroelectric body sensors can only identify the movement of the human body, that is, to identify the change of infrared light emitted by the human body, if the human is in a stationary state, pyroelectric sensors are unable to distinguish whether there is someone.
At the same time, because pyroelectric material recognition is from the body temperature of the body spontaneously out of the infrared, so with the body temperature similar to pets, cats, dogs and even the north of the radiator may lead to human sensor contact.
Improper placement of body sensors can also lead to poor signal, because the infrared radiation emitted by the human body will be attenuated by glass, curtains and other materials. Therefore, when we put the body sensor, we should pay special attention to, do not include the lens that face glass and other materials, so as not to be blocked. At the same time, do not install the body sensor directly in the wiring box, otherwise it will affect the recognition range of the sensor.
It is worth noting that it senses the movement of the human body and pets, rather than people or pets, which is determined by the principle of the human body sensor itself.
At present, the vast majority of human body sensors in the smart home market are using pyroelectric infrared sensors.
Pyroelectric effect
Due to the change of temperature, pyroelectric crystals and piezoceramics will appear on the structure of the charge center relative displacement, so that their spontaneous polarization strength changes, so as to produce different signs of bound charge at their ends, this phenomenon is called the pyroelectric effect.
To put it simply, the human body or animal body will radiate infrared rays related to its own temperature. When the infrared rays radiated radiated to the pyroelectric material, the pyroelectric material will generate a signal of related potential change. According to this signal, we can judge whether there is a human body or pet moving.
However, because the infrared light emitted by the human body is very weak, most of the human body sensors will add a Fresnel lens that gathers the infrared light of the human body to achieve more accurate detection of human movement.
From the principle point of view, most of the current use of pyroelectric body sensors can only identify the movement of the human body, that is, to identify the change of infrared light emitted by the human body, if the human is in a stationary state, pyroelectric sensors are unable to distinguish whether there is someone.
At the same time, because pyroelectric material recognition is from the body temperature of the body spontaneously out of the infrared, so with the body temperature similar to pets, cats, dogs and even the north of the radiator may lead to human sensor contact.
Improper placement of body sensors can also lead to poor signal, because the infrared radiation emitted by the human body will be attenuated by glass, curtains and other materials. Therefore, when we put the body sensor, we should pay special attention to, do not include the lens that face glass and other materials, so as not to be blocked. At the same time, do not install the body sensor directly in the wiring box, otherwise it will affect the recognition range of the sensor.
Know the above principle, now can get why the installation of the body sensor is so important?
