David Unaipon ( born David Ngunaitponi ) ( 28 September 1872 - 7 February 1967 ) was a well-known Indigenous Australian of the Ngarrindjeri people , a preacher , inventor and writer .
David Unaipon ( born David Ngunaitponi ; 28 September 1872 - 7 February 1967 ) was an indigenous Australian preacher , inventor , writer and activist .