Detecting charged pions emitted from antiproton annihilation on nuclei is a well-established technique utilized to determine annihilation vertex positions, crucial for several experiments in the antimatter field. For the past decade, a detector composed of plastic scintillating bars has been integral to the ASACUSA experiment, employed in both antihydrogen formation experiments and annihilation cross-section measurements. This work outlines its design and operations, focusing on its role in these experimental applications.