Nowadays, the systems that provide the ability to harvest energy from the surrounding are of interest. Mechanical energy was chosen as one of various energies to scavenge from surrounding. The systems use the direct piezoelectric effect, conversion of strain to electrical energy and storage energy for later use. The commercial soft PZT (APC 850) ceramics were used in this experiment. Discs were prepared by cold isostatic pressing (CIP) at 240 MPa prior to sintering at 1200C. Sintered pellets were then surface-polished and, silver electroded on both surfaces prior to poling in silicone oil at 70C with an applied electric field at 30 kV/cm. The obtained d33 from the ceramics was 550 pC/N. The prototype of the energy harvesting module was consisted of vibrating generator unit, bridge rectifier, AC-DC converter and capacitors. Various metal substrates were attached to the sintered discs and the power densities generated were investigated and recorded.