Fecha de publicación: 19/09/2024 Fuente: Wipo "Sensorization" A user classification system is provided. The system includes a user device and a sensor for producing a sensor signal. The sensor is configured to produce a sensor signal, and comprises a controller. The controller is configured to: provide drive signals to be transmitted by the sensor as ultrasonic pulses; and receive and process signals recorded by the sensor. The signals recorded by the sensor comprise one or more recorded reflections of the ultrasonic pulses transmitted by the sensor. The system classifies a user of the system based on the sensor signal.