24GHz millimeter wave radar basic knowledge of the principle of sensors in the human body

I. Introduction

With the rapid development of science and technology, smart homes have gradually integrated into our daily lives and become an indispensable part of modern families. In the smart home system, the human body presence sensor is a key component, which is of great significance to improve the intelligence level of the home environment. 24GHz millimeter wave radar technology, with its unique advantages, plays an important role in the presence of human sensors. In this paper, the basic knowledge of 24GHz millimeter wave radar and its application principle in human presence sensor will be elaborated in detail, in order to provide readers with in-depth understanding and understanding.

2. Basic knowledge of 24GHz millimeter wave radar

24GHz millimeter wave radar is a kind of radar system that works in the millimeter wave band, which has many advantages, such as high resolution, strong anti-interference ability, good penetration and so on. Below we will introduce its basic knowledge in detail from the aspects of working principle and main characteristics.

Working principle

The working principle of 24GHz millimeter wave radar is mainly based on the emission, propagation and reception of electromagnetic waves. The radar system first emits millimeter wave signals, and when these signals encounter the target object, some of the signals will be reflected back, received by the radar and processed. By analyzing the reflected signal, the radar system can obtain the distance, speed, direction and other information of the target object. This working principle enables 24GHz mmwave radar to have high accuracy and sensitivity when detecting target objects.

Main feature

(1) High resolution: Due to the short wavelength of millimeter wave, it has a high resolution and can accurately identify the shape and position of the target object. This allows the 24GHz millimeter wave radar to accurately determine the position and movement of the human body when detecting the presence of the human body.

(2) Strong anti-interference ability: millimeter wave radar has strong anti-interference ability and can work stably in a complex electromagnetic environment. This makes it have a wide range of application prospects in smart home and other environments.

(3) Good penetration: millimeter wave radar can penetrate some non-metallic materials and obstacles, such as glass, plastic, etc. This feature enables it to achieve barrier-free detection of human presence in smart homes.

Third, the human body has a sensor principle

Human presence sensor is a sensor device that can detect the presence of the human body, which is widely used in smart home, security monitoring and other fields. The human presence sensor based on 24GHz millimeter wave radar, with its unique advantages, has become a research hotspot in this field.

Working mechanism

The human presence sensor based on 24GHz millimeter wave radar detects the presence of the human body by transmitting millimeter wave signals and receiving reflected signals. When the human body enters the detection range of the sensor, the movement and shape change of the human body will cause the intensity and phase of the reflected signal to change. By analyzing these changes, the sensor can determine the presence and movement of the human body.

Specifically, the sensors first emit millimeter-wave signals into the surrounding space, which are reflected when they encounter the human body. The reflected signal carries information such as the position and speed of the human body, which is received by the sensor and analyzed and processed by the internal signal processing system. The sensor can judge the existence state of the human body according to the intensity and frequency of the reflected signal, such as static, walking, running and so on.

Signal processing

The reflected signal received by the sensor needs to undergo a series of complex signal processing processes to extract useful information. First, the sensor amplifies and filters the incoming signal to eliminate noise and interference. Then, the analog signal is converted to digital signal by analog-to-digital conversion for subsequent digital signal processing.

In the digital signal processing phase, the sensor uses a series of algorithms to analyze the signal. For example, the frequency characteristics of the reflected signal can be obtained by using FFT algorithm to analyze the spectrum of the signal. Using CFAR algorithm to process the constant false alarm rate of the signal can improve the accuracy of the sensor's detection of human presence.

Through these complex signal processing processes, the sensor can accurately identify the presence of the human body and its dynamic changes, providing reliable human detection functions for smart home systems.

Environmental adaptability

In practical applications, human presence sensors need to face a variety of complex environmental conditions, such as temperature, humidity, light and other factors. 24GHz millimeter wave radar, due to its unique frequency band characteristics, can reduce the impact of these environmental factors to a certain extent.

First of all, millimeter wave radar works in high frequency band, and has good anti-interference ability for some common interference sources, such as low-frequency noise and electromagnetic interference. This enables the sensor to work stably in a complex electromagnetic environment.

Secondly, millimeter wave radar has strong penetration and can penetrate some non-metallic materials and obstacles. This allows the sensor to maintain good performance when the installation location is limited or when it needs to penetrate obstacles for human detection.

In addition, by optimizing the sensor design and signal processing algorithm, its adaptability and stability in different environments can be further improved. For example, the adaptive filter algorithm is used to process the signal, and the parameters of the filter can be automatically adjusted to adapt to the signal changes under different environmental conditions.

Fourth, the application advantages of 24GHz millimeter wave radar in human presence sensors

The human presence sensor based on 24GHz millimeter wave radar has significant application advantages in the field of smart home, mainly reflected in the following aspects:

High precision detection

Due to the high resolution of 24GHz millimeter wave radar, the sensor can accurately detect the position and shape changes of the human body. This high-precision detection capability allows the sensor to accurately determine the presence or absence of the human body, as well as the movement and posture of the human body. In smart home systems, this helps to achieve more accurate human body recognition and movement analysis, thereby improving the level of intelligence of the system.

Strong anti-interference ability

There may be various sources of electromagnetic interference in the smart home environment, such as wireless devices and household appliances. However, 24GHz mmwave radar has strong anti-interference ability and can work stably in these complex environments. This enables the human presence sensor based on 24GHz millimeter wave radar to maintain high reliability detection performance in a variety of electromagnetic environments, ensuring the stable operation of smart home systems.

Strong penetration

In smart home systems, human presence sensors usually need to be installed behind obstacles such as walls and glass to achieve coverage of the entire living space. The penetration of the 24GHz mmwave radar enables the sensor to penetrate these obstacles and achieve barrier-free detection of the presence of the human body. This feature makes the sensor more flexible and convenient in installation and use, and can adapt to the layout and needs of different home environments.

Privacy protection

Compared to traditional vision sensors, 24GHz mmwave radar does not capture and transmit any image or video information, so it can better protect the privacy rights of users. It only determines the presence and motion state of the human body by detecting the reflected signal of the human body, and does not involve any visual information processing. In smart home applications, this privacy protection feature makes the human presence sensor based on 24GHz millimeter wave radar more in line with the privacy needs of users.

V. Application cases and prospects

The human presence sensor based on 24GHz millimeter wave radar has been widely used in the field of smart home, and has shown broad prospects. Here are some specific application cases and prospects:

Intelligent lighting system

In the intelligent lighting system, the human presence sensor based on the 24GHz millimeter wave radar can monitor the human movement in the room in real time. When the sensor detects the human body entering the room, it can automatically turn on the light; When the human body leaves the room, the lights are automatically turned off. This intelligent lighting system not only improves the convenience of living, but also helps to save energy and reduce energy consumption.

Intelligent security system

In intelligent security systems, there are sensors in the human body that can be used to monitor the activity status of family members in real time. When the sensor detects abnormal human activity or a long time of no activity, it can trigger the alarm system to remind the user or relevant agencies to deal with it in time. This security system helps to improve the safety of the home and guard against potential security risks.

Intelligent home appliance control

Human presence sensors based on 24GHz millimeter wave radar can also be controlled in tandem with smart home appliances. For example, when the sensor detects that the human body is near the TV, it can automatically turn on the TV and adjust the appropriate volume and brightness; When the human body leaves, the TV is automatically turned off. This smart home appliance control makes the home environment more intelligent and comfortable.

With the continuous progress of technology and the continuous expansion of application scenarios, human presence sensors based on 24GHz millimeter wave radar will play a greater role in the field of smart home. In the future, we can expect more innovative applications in intelligent environmental regulation and intelligent health monitoring. For example, by combining sensor data such as temperature and humidity, the smart home environment can be automatically adjusted; Provide personalized health management and advice by monitoring human movement status and sleep quality.

Vi. Conclusion

In summary, 24GHz millimeter wave radar plays an important role in human presence sensors with its unique working principle and advantages. Through the introduction of the basic knowledge of 24GHz millimeter wave radar and its application principle in the human presence sensor in detail, we can have a deeper understanding of its application value and potential in the field of smart home. With the continuous development and improvement of technology, it is believed that human presence sensors based on 24GHz millimeter wave radar will occupy an important position in the future smart home market, bringing more convenience and security to people's lives.