Corresponding to the sensor 2211, the cover 222 has an opening portion 222a. When the sensing unit 221 is rotated to a first angle, the sensor 2211 (especially the sensing element 2211A) corresponds to the opening portion 222a of the cover 222. In other words, the sensing element 2211A is behind the lens 2211B (when the sensing unit 221 is rotated to the first angle in normal operation). In normal operation, the sensing element 2211A receives sensing signals such as the exterior light, infrared or microwave reflections through the lens 2211B. The type of received sensing signal depends on the type of the sensor 2211 (or the sensing unit 221). At this time, the operating parameter adjusting element 2213 is at the back of the sensing unit 221.

Specifically, the sensing unit 221 and the light body 21 are rotatably connected. For example, the sensing unit 221 is connected to a rotation axis (and the rotation axis is connected to the light body), or the sensing unit 221 can be disposed on a rail on the light body 21. As such, the sensing unit 221 can rotate relative to the light body 21. In practical applications, a rotation angle limit is set to limit the sensing unit 221 rotating relative to the light body 21, in order to avoid breaking the power wires (such as the power wires 24 shown in FIG. 5) connecting the sensing unit 221 and the exterior electrical power source due to twisting the power wires when the rotation angle is too large.