The present discosure provides a method of operating a datalogger adapted for logging sensor data from an absorbent article having at least one sensor element, the method comprising: determining an external event and on determination of the external event, transitioning from a first operating condition to a second operating condition. The external event can be an event selected from: a disconnection event in which the datalogger is disconnected from the absorbent article a connection event in which the datalogger is connected to an absorbent article a charge event in which the datalogger is connected to a charging station and a user interaction event in which the user interacts with a user interface element of the datalogger. The first and second operation conditions can be selected from: a datalogging condition a standby condition a status notification condition and a data transmission condition. The present disclosure also provides a datalogger adapted for logging sensor data from an absorbent article having at least one sensor element, the datalogger comprising: a processor configured to determine an external event and, on determination of the external event, to transition from a first operating condition to a second operating condition.
