In the current era of rapid technological development, smart homes are transforming our way of life at an unprecedented pace. From intelligent lighting to smart security, from smart appliance control to care for special groups, smart homes aim to create a more convenient, comfortable, and safe living environment for people. Behind this, the radar module, as a key technology, is playing a pivotal role and has become the core force driving the development of smart homes.
一、Working Principles and Technical Advantages of Radar Modules
（一）Working Principles
Radar modules detect target objects by leveraging the properties of electromagnetic waves. Common millimeter-wave radar modules operate in the millimeter-wave frequency band (30GHz–300GHz). They emit millimeter-wave signals, receive the reflected signals, and analyze information such as time delay, frequency change, and phase change of the signals to achieve detection, ranging, velocity measurement, and angle measurement of target objects. For example, when radar signals encounter a human body, they are reflected, and the reflected signals carry information about the body's position and movement status. The radar module processes and analyzes these reflected signals to accurately sense the presence and activities of humans.
（二）Technical Advantages
High-precision Detection: Radar modules can accurately identify the number, position, and movements of indoor personnel. Take advanced millimeter-wave radar as an example, its ranging accuracy can reach centimeter level, enabling precise determination of a person’s specific position in a room and even sensing subtle movements such as breathing and heartbeat. This provides extremely accurate data support for smart home systems, allowing them to better understand users’ needs and intentions and deliver personalized services.
Strong Anti-interference Capability: In complex home environments with numerous wireless devices and obstacles, radar modules exhibit excellent anti-interference capabilities. They are not disturbed by other wireless devices and can effectively handle indoor object obstructions. For instance, millimeter-wave radar signals can penetrate non-metallic materials such as glass and plastic. Even when faced with obstacles like furniture or curtains, they can still stably detect target objects and maintain high detection accuracy, ensuring the reliable operation of smart home systems in various environments.
Privacy and Security Protection: Unlike technologies that rely on image recognition, radar modules only detect and range through reflected electromagnetic wave signals without acquiring users’ image information, which largely protects users’ privacy and security. Especially in home environments, users need not worry about personal privacy violations and can enjoy the convenience of smart homes with greater peace of mind.
二、Diversified Application Scenarios of Radar Modules in Smart Homes
（一）Intelligent Lighting Systems
In traditional home lighting, people often need to manually switch lights on and off, which is not only inconvenient but also prone to energy waste. The application of radar modules has brought a new solution to intelligent lighting. By installing radar modules in suitable indoor locations, they can real-time detect personnel activities. When someone enters a room, the radar module quickly senses and automatically triggers the lights to turn on; when the person leaves the room, the lights automatically turn off after a preset delay. This process requires no manual operation, achieving intelligent control of "lights on when people come, lights off when people leave," which greatly improves the convenience of lighting and effectively avoids energy waste caused by forgetting to turn off lights, achieving energy conservation and environmental protection. In addition, radar modules can also intelligently adjust the brightness and color temperature of lights according to the position and activity status of personnel in the room. For example, when users are active in a reading area, the lights are automatically adjusted to a brightness and color temperature suitable for reading; when users are relaxing in a leisure area, the lights are adjusted to a soft and warm atmosphere, providing users with a more comfortable lighting experience.
（二）Intelligent Security Systems
Security is a top priority in family life, and radar modules play a key role in the field of intelligent security. In terms of home perimeter protection, radar modules installed on doors, windows, walls, and other positions can real-time monitor whether there are abnormal personnel approaching or breaking in. When a stranger enters the monitoring area, the radar module can quickly detect human movement and, through linkage with the security system, immediately trigger an alarm and send a notification to the user’s mobile phone, allowing the user to understand the home security situation in the first time. Indoors, radar modules can also be used to detect abnormal behaviors. For example, by continuously analyzing personnel activity patterns, they can identify abnormal situations such as falls or prolonged stillness and promptly issue alarms to notify family members or relevant rescue agencies, providing all-round protection for the safety of family members. Compared with traditional security sensors (such as infrared sensors), radar modules have higher accuracy and reliability, effectively reducing false alarm rates and escorting home security.
（三）Intelligent Appliance Control
Smart Air Conditioners: The combination of radar modules and smart air conditioners enables intelligent operation of the air conditioners. Through radar modules installed indoors, the number, position, and activity status of indoor personnel can be real-time detected. Based on this information, the air conditioner can automatically adjust the temperature, wind speed, and direction. For example, when it is detected that personnel are concentrated in a certain area of the room, the air conditioner automatically adjusts the air direction to that area to improve cooling or heating effects; when the number of indoor personnel changes, the operating power of the air conditioner is automatically adjusted to achieve the best comfort and energy-saving effect. This intelligent control method allows users to enjoy a comfortable indoor environment without manually adjusting the air conditioner, while also greatly improving energy utilization efficiency.
Smart TVs: Radar modules also play an important role in smart TV systems. They can identify the user’s viewing position and posture and automatically adjust the angle and brightness of the TV screen. When users watch TV from different positions, the radar module real-time monitors the user’s position information and transmits it to the TV, which automatically adjusts the screen angle to ensure that users always obtain the best viewing angle; at the same time, the screen brightness is automatically adjusted according to the ambient light and the user’s viewing distance, which not only protects the user’s eyes but also enhances the viewing experience. In addition, some advanced radar modules also support gesture control functions, allowing users to control TV playback, pause, channel switching, and other functions through simple gestures, bringing a more convenient and intelligent interactive experience to users.
（四）Intelligent Door, Window, and Curtain Control
The control of intelligent doors, windows, and curtains is an important aspect of improving home convenience and safety. The application of radar modules in this field has realized the automatic control of doors, windows, and curtains. After installing radar modules on doors and windows, when someone is detected approaching, the doors and windows can automatically open to facilitate user entry and exit; when the person leaves, the doors and windows automatically close, which not only improves home convenience but also enhances safety, effectively preventing safety hazards caused by forgetting to close doors or windows. For curtain control, radar modules can automatically adjust the opening and closing degree of curtains according to user activities and light changes. For example, in the morning, when the sunlight gradually becomes stronger, the radar module detects the change in indoor light and automatically opens the curtains to let the sunlight in; when users are active by the window, the opening and closing angle of the curtains is automatically adjusted according to the user’s position and activity status, providing a comfortable light environment for users while protecting their privacy.
（五）Intelligent Space Layout Optimization
Understanding the living habits and preferences of family members is crucial for optimizing home space layout. Radar modules provide strong support for intelligent space layout optimization by collecting and analyzing indoor personnel activity data. Through long-term monitoring of personnel activity trajectories, residence time, and frequently used areas in each room, smart home systems can gain an in-depth understanding of family members’ living habits. For example, if it is found that a family member often reads in a certain corner of the living room, a comfortable reading area can be considered to be added in that position, equipped with appropriate lighting and furniture; if a room is found to be used less frequently, the space can be re-planned and utilized according to actual needs. Through this data-based intelligent space layout optimization, the utilization rate and comfort of home space can be improved, making the home environment more in line with the living needs of family members.
