mmWave sensing in smart washlets

After COVID-19 breaks out in 2020, it has changed everyone’s life and altered people’s attitudes toward public health. Users need non-contact equipment to avoid touching contaminated objects directly, especially in restrooms and other public spaces.

A smart washlet uses sensors to detect its users’ position. The detected results help it recognize whether the user intends to use or leave the washlet or he/she is seated already. Thus, users do not need to press any button or touch the lit or seat by hand. Conventionally, infrared sensors are used to measure the position of users, but the results usually deviate because such sensors are affected by temperature, humidity, and the lighting condition of the environment.

The latest sensing technology adopted by smart washlets is 24GHz mmWave radar sensing. It uses similar technologies as collision-avoidance radars in the most advanced vehicles. By taking advantage of technology scaling and integration, the sensing technologies used by the automotive radars can be made smaller and less expansive and become consumer-electronics grade products. The sensor emits a modulated electromagnetic wave signal at an ultra-high frequency (24GHz, 10 times the frequency of Bluetooth), and the wave is reflected by the washlet user. The sensor receives and analyzes the reflected signals by a built-in digital signal processor; thus the distance and position information can be extracted.

Smart washlets with mmWave radar sensors can accurately measure users’ position, and the washlets are able to determine whether it should open the lit or flush. It can prevent users from touching contaminated surfaces. Smart washlets are going to be the next-generation appliance for lavatories, keeping us far away from contaminates and guarding our health.