This seems to do the trick

saveTask = 
  CreateScheduledTask[FrontEndExecute[FrontEndToken["Save"]], 30];
StartScheduledTask[saveTask]

This also,

Dynamic[Refresh[NotebookSave[]; DateString[], UpdateInterval -> 30]]

Of course, there's also this built-in functionality with

SetOptions[SelectedNotebook[], NotebookAutoSave -> True]

This seems to do the trick

saveTask = 
  CreateScheduledTask[FrontEndExecute[FrontEndToken["Save"]], 30];
StartScheduledTask[saveTask]

This also,

Dynamic[Refresh[NotebookSave[]; DateString[], UpdateInterval -> 30]]

Of course, there's also this built-in functionality with

SetOptions[SelectedNotebook[], NotebookAutoSave -> True]

This seems to do the trick

saveTask = 
  CreateScheduledTask[FrontEndExecute[FrontEndToken["Save"]], 30];
StartScheduledTask[saveTask]

This also,

Dynamic[Refresh[NotebookSave[]; DateString[], UpdateInterval -> 30]]

Sources:

http://stackoverflow.com/a/6982126/4712538 http://stackoverflow.com/q/7193804/4712538

This seems to do the trick

saveTask = 
  CreateScheduledTask[FrontEndExecute[FrontEndToken["Save"]], 30];
StartScheduledTask[saveTask]

This also,

Dynamic[Refresh[NotebookSave[]; DateString[], UpdateInterval -> 30]]

Of course, there's also this built-in functionality with

SetOptions[SelectedNotebook[], NotebookAutoSave -> True]