The invention relates to an autonomous lawn mower (1') comprising a control unit (5') in electrical connection with electrical connection means (8), and at least one replaceable part (7). The electrical connection means (8) is located such that connection and disconnection of the electrical connection means (8) and its counterpart (9) of the replaceable part (7) can be performed when replacing the replaceable part (7). The module for such autonomous lawn mower (1') can replace the replaceable part (7) of the lawn mower (1') and comprises a signal generation unit (11, 13, 14) and a counterpart (9) for the electrical connection means (8) of the lawn mower (1') for transmitting electrical signals to a control unit (5') of the autonomous lawn mower (1'). The autonomous lawn mower (1') forms an autonomous lawn mower system together with the module (7).
