There are several ways to harvest energy from motion. This slide will focus on piezoelectric harvesters. Piezoelectric material produces electric charge from strain. A vibration-based energy harvester can be made by designing a piezoelectric beam and affixing a mass to the end of the beam. Vibrations will induce strain on the beam and generate charge which is proportional to the strain. At or close to resonance, the electrical model is simply a sinusoidal current source in parallel with a capacitor (Cp) and a resistor (Rp). In order to maximize the harvested energy, specialized electronics are required.