Abstract: A detector is configured to be mounted to a container. The detector has a housing and a mounting arrangement for mounting the housing to a container. A sensor arrangement includes a sensor to monitor the container and to generate a sensor output signal in response to a sensed container event. A processor executes a machine learning algorithm trained to determine a class of the sensed container event for determining occupancy of the container from the sensor output signal, where the control system is configured to provide an output based on the class of sensed container event determined by the machine learning algorithm.