In the embodiment, the detector body 10 is equipped with a sound playback device 80, which is electrically connected to the control board 50. The control board 50 controls the sound playback device 80 to play sound based on the signal transmitted by the signal receiving end 12. By such arrangement, the control board 50 controls the sound playback device 80 to play sound based on the signal transmitted by the signal receiving end 12. For example, by distinguishing different signal strengths based on sound size and frequency, users can roughly judge the distance between the sound and the signal transmission device by listening to the sound, further facilitating user use.

In the embodiment, the upper surface of the detector body 10 is equipped with a sound through-hole 14, which corresponds to the sound playback device 80. By such arrangement, the sound through-hole 14 can allow sound waves to pass therethrough, allowing users to hear the sound generated by the sound playback device 80 more clearly.

In the embodiment, the detector further includes an adjustment switch 53, which is electrically connected to the control board 50. The adjustment switch 53 is configured for users to switch the signal frequency that can be detected by the antenna 30. The adjusting switch 53 can adjust the signal frequency that antenna 30 can detect, improving adaptability of the detector.

In the embodiment, the detector further includes a protective sleeve 33, which is set at the end of the antenna 30. By such arrangement, the protective sleeve 33 can protect the antenna 30 and prolong a service life of the detector.