The electronics module (100) comprises a memory (101) operable to store sensor data obtained from a sensor of or in communication with the electronics module (100). A communicator (103) is operable to transmit sensor data. A processor (105) is operable to retrieve a plurality of historic sensor data from the memory (101), and control the communicator (103) to wirelessly transmit the plurality of samples of historic sensor data in response to the processor (105) determining to transmit historic sensor data. Determining to transmit historic sensor data comprises the processor (105) determining that an external device (200) has been brought into proximity with the electronics module (100) and/or comprises the processor (105) determining that an abnormal condition is present in sensor data obtained from the sensor.