This paper presents an automated measurement setup for the electro-mechanical characterization of piezoelectric energy harvesters in cantilever configuration. The setup provides a mechanical stimulus to the harvester and concurrently acquires mechanical and electrical quantities to characterize the electro-mechanical properties of the device under test in open-circuit conditions. The setup, composed by an electrodynamic shaker, a waveform analyzer, and two laser-based positioning sensors, is fully controlled via MATLAB. The use of two laser heads allows to measure the movement of the base, so to automatically consider artefacts due to the non-ideal response of the electrodynamic shaker. The proposed measurement system is compatible with any generic piezoelectric-cantilever harvesters, and it can be exploited for advanced modelling techniques that requires extensive experimental data. The proposed measurement setup was validated through the characterization of a commercial Piezo Protection Advantage (PPA) transducer up to 300 Hz.