In the current era of rapid technological development, sensor technology, as a key component of the Internet of Things, is constantly bringing innovation and transformation to various fields. The 5.8G radar module, with its unique performance advantages, is gradually emerging and has become a powerful assistant for many industries to achieve intelligent and precise operation. 

 I. Working Principle The 5.8G radar module operates based on the principle of Doppler

microwave radar. The planar antenna inside the module emits extremely low-power electromagnetic waves. After encountering an object and being reflected, the module receives the echo. By analyzing the frequency difference (Doppler shift), signal time difference, or phase difference between the transmitted wave and the echo, information such as the motion state and distance of the object can be determined. For example, when an object moves within the detection range, the frequency of the reflected wave will change according to the moving speed of the object, and the module can accurately calculate the moving speed and direction of the object based on this.

 II. Module Characteristics

 (1) Strong Penetration Ability It can penetrate specific non-metallic materials such as plastics, wall panels, and clothes, as well as obstacles like furniture and curtains, and can accurately detect the target object in complex environments. For instance, in smart home applications, even if the human body is partially blocked, the radar module can still sense the presence and movement of the human body.

 (2) Long-distance Detection The forward detection distance ranges from 0.1 to 20m. In open spaces such as large warehouses and outdoor squares, it can effectively monitor objects at a long distance, expanding the application scope. 

 (3) Excellent Anti-interference Performance It has an outstanding ability to suppress high harmonics and other clutter interference. In the actual complex electromagnetic interference environment, it can work stably and accurately output the detection results. For example, in an industrial manufacturing workshop, where a large number of electrical equipment generate interference, it can still accurately detect the operation status of the equipment and the activities of personnel. 

 (4) Low-power Consumption Design The working voltage is 2.7V - 3.3V, and the working current is as low as below 18μA. In battery-powered smart home devices such as smart door locks and night lights, the low power consumption can extend the battery life of the device, reduce the frequency of battery replacement, and improve the user experience. 

 III. Application Scenarios

 (1) Smart Security Field Smart Door Lock: When the user approaches with an authorized device, the radar module detects the approach of the human body and triggers the door lock to unlock automatically. Its penetration ability avoids the failure of the induction caused by occlusion. Video Intercom Doorbell and Smart Peephole: It can monitor in real time whether there are people staying or lingering in front of the door. When an abnormality is detected, it will send an alarm to the user's mobile phone and activate the camera to take pictures. With strong anti-interference ability, it can reduce false alarms. Smart Camera: Equipped with a 5.8G radar module, when someone enters the monitoring range, the radar quickly detects the movement of the human body and triggers the camera to automatically focus and track for shooting, improving the efficiency of security monitoring in large public places. 

 (2) Smart Lighting Field Downlights/Bulbs: In corridors and stairwells, they can turn on when people come and turn off when people leave. When installed at a height of 3 - 4 meters, the induction radius is 3 - 6 meters. The ultra-small size (14×14mm) does not block the lamp beads, solves the power coupling interference, and some can be customized with PWM output. Combined with the photosensitive logic, it can save energy. T8 Fluorescent Tubes: The networked type is used in garages and parking lots. It adopts an integrated design of 5.8G microwave radar + Bluetooth mesh. Cooperating with the IoT system platform, the induction distance can be set through the APP, and multiple wireless communication solutions are available, with strong anti-interference ability. For the induction type, when installed at a height of 3 meters, the induction radius can be adjusted between 3 - 6 meters. The customized PWM output can save energy, and the fixed-frequency design does not self-excite. High Bay Lights: Used in large warehouses and factories, it supports extremely high installation heights (15 - 30 meters) and long-distance applications. It can be combined with Bluetooth and 433 modules to achieve various functions, and after optimization, it can operate stably even when installed centrally in complex environments. Ceiling Lights: Integrated with a 4-bit DIP switch to adjust the induction distance, time, and photosensitive function. The cable socket interface is plug-and-play, and the limit hole is convenient for fixing. Cabinet Lights: When someone approaches or waves their hand, the lights gradually turn on. It adopts an ultra-low-cost solution, directly drives the load lights, supports PWM output, and can be installed in a concealed way. Night Lights: It supports battery power supply, with a low power consumption of 40μA. The distance and delay can be adjusted, and it can be set to sense the approach or a wave of the hand, with long battery life and low maintenance. Vanity Lights: It supports micro-motion detection, has a user-friendly structure, and does not require opening holes on the mirror surface. It can operate stably after dealing with various interferences. Table Lamps: It supports the detection of presence or micro-motion, adopts the FMCW ranging mode, eliminates false interference, and provides comfortable lighting.

 (3) Smart Home Field Smart Home Appliance Control: In smart home appliances such as smart refrigerators and washing machines, it can realize the induction of human approach and departure. When a person approaches, the device activates the corresponding functions, and when the person leaves, it enters the energy-saving state. Smart Bathroom: The vanity light turns on when people come and turns off when people leave; the sterilization light works in the opposite way; the smart toilet automatically opens the lid and adjusts the temperature of the seat ring; the induction trash can automatically opens the lid; the smart bathroom heater automatically adjusts the temperature and ventilation; the induction soap dispenser extrudes soap when it detects the approach of a hand. The induction distance can be accurately set to provide a convenient and hygienic experience. Other Applications: It can be linked with other devices in the smart home system. When it detects that the user is home, it automatically turns on the lights and curtains and adjusts the temperature and humidity; when it detects that the user is asleep, it turns off unnecessary electrical appliances and adjusts the air conditioning temperature, achieving the intelligent and automated control of the whole house.

 (4) Other Fields Library Scenarios: It can detect the entry and exit of readers with high precision, not affected by environmental factors such as light. When someone enters the reading area, it triggers the lighting and air conditioning to turn on to a comfortable mode; when there is no one, it reduces the lighting brightness and adjusts the air conditioning temperature to save energy. It can also be linked with the evacuation indication system in case of an emergency. Outdoor and Public Area Monitoring: In places such as parks, squares, shopping malls, and stations, it can monitor and count the pedestrian flow in real time. Its long-distance detection and strong penetration ability provide data support for the management and safety protection of these places. With its unique performance advantages, the 5.8G radar module shows great application potential in many fields and injects new vitality into the intelligent development of various industries. With the progress of technology and the reduction of costs, it is expected to be widely applied in more scenarios, bringing more convenience and innovation to people's lives and work.