"The berimbau (; Brazilian Portuguese: [beɾĩˈbaw]) is a single-string percussion instrument, a musical bow, from Brazil. Originally from Africa where it receives different names, the berimbau was eventually incorporated into the practice of the Afro-Brazilian martial art capoeira, the berimbau (the soul of capoeira) leads the capoeiristas movement in the roda—the faster the berimbau is playing the faster the capoeirista moves in the game. The instrument is known for being the subject matter of a popular song by Brazilian guitarist Baden Powell, with lyrics by Vinicius de Moraes. The instrument is also a part of Candomblé-de-caboclo tradition." Source : Wikipedia
After print it, you should grab a thin piece of wire and small amount of string and perform the assembly. Dental floss works too.