This paper presents a small electromagnetic generator for vibration energy harvesting, with a component volume of 0.1 cm³ and a practical volume of 0.15 cm³. The generator is optimized for low ambient vibration levels and utilizes four magnets arranged on an etched cantilever with a wound coil within the moving magnetic field. The device produces 46 μW in a resistive load of 4 kΩ from just 0.59 m/s² acceleration levels at its resonant frequency of 52 Hz. A voltage of 428 mVrms was obtained from the generator with a 2300 turn coil, which is sufficient for subsequent rectification and voltage step-up circuitry. The generator delivers 30% of the power supplied from the environment to useful electrical power in the load. This generator compares very favourably with other demonstrated examples in the literature, both in terms of normalized power density and efficiency. The generator is designed to operate within the frequency range of 43 Hz to 109 Hz, where vibrations are present in the application environment. The generator is capable of producing useful power from a vibration level of 60 mg, delivering 46 μW to a resistive load of 4 kΩ when shaken at its resonant frequency of 52 Hz. This is a power density of 307 μW/m³. The generator delivers 30% of the total power dissipated in the generator to electrical power in the load. The generator compares very favourably with other demonstrated examples in the literature, both in terms of normalized power density and efficiency. The generator is based on the theory of resonant generators, which can be modelled as a second-order, spring–mass–damper system with base excitation. The generator is designed to operate at its resonant frequency and for optimum energy extraction should be designed such that this coincides with the vibrations present in the intended application environment. The theory of inertial-based generators is well documented and will only be briefly summarized here. Assuming the generator is driven by a harmonic base excitation, it will move out of phase with the mass at resonance resulting in a net displacement between the mass and the frame. The generator is designed to operate at these lower frequencies and at an rms acceleration of 0.59 m/s². This frequency range and acceleration level is indicative of the vibration levels found in typical industrial applications. The generator is a miniaturized form of a previous larger scale design. The generator uses miniature discrete components fabricated using a variety of conventional manufacturing processes. This enables the generator to exploit the advantages of bulk magnetic material properties and large coil winding density thereby demonstrating useable levels of power from a compact design. The generator is capable of producing useful power from only 0.59 m/s² of ambient vibration. A prototype rectification and multiplier circuit has been fitted to the generator, capable of chargingThis paper presents a small electromagnetic generator for vibration energy harvesting, with a component volume of 0.1 cm³ and a practical volume of 0.15 cm³. The generator is optimized for low ambient vibration levels and utilizes four magnets arranged on an etched cantilever with a wound coil within the moving magnetic field. The device produces 46 μW in a resistive load of 4 kΩ from just 0.59 m/s² acceleration levels at its resonant frequency of 52 Hz. A voltage of 428 mVrms was obtained from the generator with a 2300 turn coil, which is sufficient for subsequent rectification and voltage step-up circuitry. The generator delivers 30% of the power supplied from the environment to useful electrical power in the load. This generator compares very favourably with other demonstrated examples in the literature, both in terms of normalized power density and efficiency. The generator is designed to operate within the frequency range of 43 Hz to 109 Hz, where vibrations are present in the application environment. The generator is capable of producing useful power from a vibration level of 60 mg, delivering 46 μW to a resistive load of 4 kΩ when shaken at its resonant frequency of 52 Hz. This is a power density of 307 μW/m³. The generator delivers 30% of the total power dissipated in the generator to electrical power in the load. The generator compares very favourably with other demonstrated examples in the literature, both in terms of normalized power density and efficiency. The generator is based on the theory of resonant generators, which can be modelled as a second-order, spring–mass–damper system with base excitation. The generator is designed to operate at its resonant frequency and for optimum energy extraction should be designed such that this coincides with the vibrations present in the intended application environment. The theory of inertial-based generators is well documented and will only be briefly summarized here. Assuming the generator is driven by a harmonic base excitation, it will move out of phase with the mass at resonance resulting in a net displacement between the mass and the frame. The generator is designed to operate at these lower frequencies and at an rms acceleration of 0.59 m/s². This frequency range and acceleration level is indicative of the vibration levels found in typical industrial applications. The generator is a miniaturized form of a previous larger scale design. The generator uses miniature discrete components fabricated using a variety of conventional manufacturing processes. This enables the generator to exploit the advantages of bulk magnetic material properties and large coil winding density thereby demonstrating useable levels of power from a compact design. The generator is capable of producing useful power from only 0.59 m/s² of ambient vibration. A prototype rectification and multiplier circuit has been fitted to the generator, capable of charging