The piezoelectric buzzer enables deep integration with ultrasonic radars and vehicle anti-intrusion solutions to deliver full-scenario active audible and visual alert functions. It precisely matches distance warning and blind-spot monitoring signals detected by radars, and interlocks with the vehicle anti-intrusion monitoring system. When the vehicle detects surrounding obstacles, close-range movements, unauthorized intrusion or abnormal touches, the buzzer rapidly emits clear warning sounds to actively alert occupants of potential risks. As a critical sound-generating unit for onboard active warning, it features fast response and stable operation, making up for the lack of audio alerts in vehicle perception systems. It comprehensively improves safety protection during driving and parking, and suits safety warning applications for various passenger vehicles and intelligent vehicles.