User characteristics

The users of the system need not have any technical expertise or previous experience of using such devices. The only action required from the users should be switching the device On/Off. The application must perfom all initialisation automatically upon start up. The users do not need to be presented with a Graphical User Interface (GUI) as no further interaction should be required from the users.

The users must be capable of recharging the batteries and switching the device on upon usage and switching it off once finished.