Optionally, the ALS assembly 714 is also used to cause switching between the daytime and night modes, and enable/disable the IR illuminators 1105 and the infrared filter 1134. In some implementations, the lens holder 1120 is supported by the infrared filter 1134 to protect lenses in the lens assembly 704 from being pushed when a user touches or presses the front cover plate 708. The doorbell camera 106 may include at least a sensor board 1108, a main board 1110 and a secondary board 1112 that are stacked within the device housing 702. In some implementations, the sensor board 1108 includes a connector 1108A that is coupled to another connector of the main board 1110 directly. Alternatively, a flexible cable is optionally connected to the connector 1108A for electrically coupling the main board 1110 to the sensor board 1108. In some implementations, two ends of a flexible printed circuit FPC 1126 are electrically coupled to a respective connector at the main board 1110 and the secondary board to couple them to each other.