When the ultrasonic distance between the module and the obstacle exceeds the upper limit or lower limit, the buzzer alarm.

当超声波模块与障碍物之间的距离超过设置的上限值或者下限值时，蜂鸣器发出报警。

youdao

For months now I've been waking up ahead of my alarm clock and let me tell you, it feels awesome to wake up on your own and not to the sound of a buzzer.

我们不应该每天都在闹钟的尖叫声中醒来，然后咆哮着将拳头挥向闹钟。 通过几个月的调整，我现在每天都比闹钟早“醒”。

youdao

It was late at night. Fortunately, the buzzer of my homemade burglar alarm woke me up.

那是深夜，幸好我自制的警报器把我吵醒了。

youdao

The proposed alarm could take any number of forms, from a buzzer, to a flashing light or bed shaking motor.

ENGADGET: Sony patent application puts electrodes in a pillow, eases you out of slumber