In the current era of rapid technological development, smart technologies are penetrating every corner of people's lives at an unprecedented pace, and the field of bathroom fixtures is no exception. From traditional simple-function appliances, bathroom fixtures are striding toward intelligence and humanization. In this wave of transformation, radar modules, as a key technology, play a pivotal role, injecting strong impetus into the intelligent upgrading of bathroom fixtures.??

I. Working Principle of Radar Modules??

Radar is essentially an electronic device that detects targets using electromagnetic waves, operating based on the principle of electromagnetic wave transmission and reception. When a radar module works, it actively emits electromagnetic waves that propagate through space. When these waves encounter target objects such as the human body, they reflect back. The radar module receives the reflected electromagnetic waves and accurately analyzes the differences between the transmitted and received waves, such as time differences and frequency differences, to obtain multiple key pieces of information about the target object, including the distance from the target to the electromagnetic wave emission point, the rate of distance change (i.e., radial velocity), azimuth, and angle. This working principle enables radar modules to accurately sense the presence and movement status of target objects in complex environments.??

Among many radar technologies, those applied to the bathroom fixture field mainly include Doppler radar technology and Frequency-Modulated Continuous-Wave (FMCW) radar technology. Doppler radar technology utilizes the Doppler effect: when a target object moves relative to the radar module, the frequency of the reflected wave changes. By detecting this frequency change, the radar module can determine whether the target object is approaching or moving away and its speed. FMCW radar technology, on the other hand, emits electromagnetic waves with continuously changing frequencies over time and analyzes the frequency difference between the received and transmitted waves to accurately measure the distance to the target object while monitoring its movement status.??

II. Application Scenarios of Radar Modules in Bathroom Fixtures??

(1) Smart Toilets??

Automatic Sensing Lid Opening/Closing**: In traditional smart toilets, the automatic lid opening/closing function often relies on infrared sensing technology. However, infrared sensing has many limitations, such as being greatly affected by environmental temperature, which can easily lead to misjudgments and malfunctions in winter. In contrast, radar modules exhibit significant advantages. When a user approaches the smart toilet within a set distance (e.g., 1–2 meters), the radar module can quickly detect the human body's approach and promptly output a signal to the single-chip microcomputer, which then controls the toilet lid to open automatically. After the user leaves the toilet by a certain distance, the radar module can also keenly capture the information of the human body moving away, triggering the single-chip microcomputer to control the toilet lid to close automatically. This process requires no manual operation, which not only greatly improves convenience but also reduces bacterial transmission and effectively prevents cross-infection, making it particularly suitable for crowded environments with high hygiene requirements, such as hospitals, schools, hotels, and offices.??

Automatic Flushing**: The radar module can accurately determine whether the user has finished using the toilet and left. When the user stands up and leaves the toilet's sensing range, the radar module detects the signal of the human body moving away and immediately sends an instruction to the flushing system to achieve automatic flushing. Compared with traditional button flushing, this automatic flushing method is more hygienic and convenient, avoiding direct contact with toilet buttons and reducing the risk of bacterial transmission. Moreover, by reasonably setting the radar's sensing distance and time, the flushing timing can be optimized according to different scenarios and needs to achieve water conservation.??

Automatic Toilet Seat Control**: Some toilet seats under smart toilet lids have also begun to use radar modules for smarter control. For example, when a user approaches the toilet, the radar module can not only control the toilet lid to open but also control the toilet seat to flip up automatically via gesture sensing for the user's convenience. After use, the toilet seat can automatically fall back under the radar module's control, achieving fully touchless operation and further enhancing the convenience and hygiene of the user experience.??

Anti-Misoperation Function**: In home bathroom environments with frequent human movement, traditional sensing technologies are prone to misoperations due to the accidental approach of surrounding people, causing unnecessary actions such as frequent toilet lid opening/closing and flushing. The application of millimeter-wave radar technology in smart toilet anti-misoperation systems effectively solves this problem. Millimeter-wave radar can monitor personnel activities in the bathroom in real time and identify and analyze human behaviors through intelligent algorithms. It only triggers the toilet's related functions when detecting someone approaching the toilet and being within a reasonable usage range, avoiding false triggers caused by passersby and greatly improving the stability and reliability of smart toilet use.??

(2) Smart Vanity Lights??

As an important lighting device in bathroom spaces, the intelligence level of vanity lights directly affects the user experience. The application of Feasycom's radar sensor module in vanity lights enables intelligent on/off control. When someone approaches the mirror, the radar sensor module can detect the presence of the human body in real time and quickly transmit a signal to the vanity light's control system, automatically turning on the light to provide sufficient illumination. After the person leaves the mirror by a certain distance, the radar sensor module detects the absence of the human body and controls the vanity light to turn off automatically, truly achieving the intelligent function of "lights on when people come, lights off when people leave." This intelligent control method not only facilitates the user's lighting needs in the bathroom without manual operation but also effectively saves energy and avoids power waste caused by forgetting to turn off the lights.??

(3) Smart Bathroom Heaters??

Traditional bathroom heaters have relatively single functions and cumbersome operation methods. With the application of radar modules, the intelligence level of bathroom heaters has been greatly improved. When someone approaches a smart bathroom heater, the radar sensor module can detect the presence of the human body in real time and transmit relevant signals to the heater's control system. The control system automatically adjusts the heater's temperature and wind speed according to preset programs and algorithms to provide the most suitable bathing environment. For example, in cold winter, when a user approaches the heater, it can quickly increase the temperature and adjust the wind speed to evenly cover the body with warm air, bringing a warm and comfortable bathing experience. After the person leaves the smart bathroom heater, the radar sensor module detects the departure and automatically turns off the temperature and wind speed adjustment functions, entering standby mode to avoid energy waste.??

(4) Automatic Dehumidification and Anti-Slip Warning Systems??

Automatic Dehumidification**: Due to frequent humidity, bathrooms are prone to bacterial growth and odors. The application of millimeter-wave radar technology in automatic dehumidification systems enables intelligent control of bathroom humidity. When millimeter-wave radar detects that someone is bathing in the bathroom, it immediately activates the exhaust equipment to accelerate air circulation and reduce indoor humidity. After detecting no one present, the exhaust equipment continues to operate for a period until the bathroom humidity drops below a safe threshold, effectively preventing mold growth. Additionally, by independently monitoring different bathroom areas (such as the shower area and toilet area), millimeter-wave radar can link dehumidification equipment to work directionally for different areas, improving dehumidification efficiency. At night, when the bathroom is unused, the system automatically switches to low-power mode to reduce noise and energy consumption.??

Anti-Slip Warning**: Slippery bathroom floors are a common cause of home accidents. Millimeter-wave radar can analyze human movement trajectories in the bathroom in real time through advanced posture recognition algorithms. When detecting sudden falls or abnormal postures (such as tilting or slipping), the millimeter-wave radar immediately triggers audible and visual alarms and pushes alarm information to family members' mobile phones, providing timely emergency responses for elderly people living alone or children. Meanwhile, millimeter-wave radar can also set high-risk areas (such as bathtubs and door thresholds). When someone enters these dangerous areas, warning lights automatically turn on, and voice reminders alert users to pay attention to slip prevention, effectively reducing the probability of bathroom slip accidents and ensuring user safety.??

As an important application of smart technology in the bathroom fixture field, radar modules are bringing significant changes to the intelligent upgrading of bathroom products through their unique working principles and diverse application scenarios. They not only enhance the functions and performance of bathroom fixtures but also create a more convenient, comfortable, and safe bathroom experience for users.