In accordance with the supply monitoring signal, a message is presented by the doorbell camera 106 to a user of the doorbell camera 106 to indicate whether the input AC voltage is low with respect to the supply threshold. In some implementations, the message may include a visual message displayed by the LED indicator e. g. , a single LED light, a LED display ring formed around the doorbell button 1002 on a surface of the doorbell housing 708 according to one of a set of predetermined visual patterns input AC voltage. In some implementations, the message may include an audio message broadcast by the speaker of the doorbell camera 106. In some implementations, the camera module 1004 may send to the client device 220 via a short range communication link a notification message indicating that the input AC voltage provided by the transformer 1010 is not sufficient for powering the camera module 1004. More details on the method 1500 implemented by the doorbell camera 106 are explained above with reference to FIG. 10C. Alternatively, in some implementations, at least part of the method 1050 may be implemented at the bypass unit 1012. Independently of whether the doorbell camera 106 is electrically coupled to the remote chime 1006 in place of a conventional doorbell, a supply monitoring voltage may be generated 1056 in the bypass unit 1012 based on the input AC voltage to indicate whether the input AC voltage is greater than a supply threshold. In accordance with the supply monitoring signal, a message may be presented 1058 by the bypass unit 1012 to a user of the doorbell camera 106 to indicate whether the input AC voltage is low with respect to the supply threshold.