Mikey Shirley, 21, was found in possession of the blade and cannabis in the nearby hamlet of Caldecott on December 14.
The knife, a folding pocket knife, had a blade that was more than 3in long.
Last week at Northampton Magistrates' Court Shirley, of Cunningham Close, admitted possession of a class B drug and possession of a bladed article in public.
Magistrates said the nature and seriousness of the offence warranted a custodial sentence but decided to suspend it.
Shirley was sentenced to 16 weeks in prison suspended for a year.
The knife and cannabis will be destroyed and Shirley must also pay costs of £85 and a surcharge to fund victim services of £122.