Abstract: Techniques are described for using an optical sensor to monitor light produced by an indicator light of a monitoring system. The optical sensors can monitor attributes of the indicator light in order to detect a blink pattern outputted by the indicator light. In some implementations, video data indicating a blink pattern of a device within a property is obtained. One or more attributes of the blink pattern are identified based on processing the obtained video data. A status for the device is determined based at least on the one or more identified attributes. A system action that corresponds to the status is determined. The system action corresponding to the determined status is performed.