A surface acoustic wave (SAW) on a piezoelectric substrate can excite a spin wave in a ferromagnetic film deposited on the wave path. For the identification of the magnon-phonon coupling, scattering matrix measurements with a vector network analyzer (VNA) are often used. In this method, however, frequency of SAW that can be detected is limited by the pitch of the fingers of interdigital transducers (IDTs), which hinders the application of this method to studying possible frequency conversion process in magnon-phonon coupled systems. In this work, we demonstrate a novel approach to detecting SAW-driven spin waves by using a conductive thin film as an antenna. Previous studies showed that a direct current generated at a (semi-)conductive/piezoelectric interface, referred to as acousto-electric current, is proportional to SAW power. We use the antenna as a SAW power detecter to probe the energy conversion from SAWs to spin waves.