An energy harvesting device includes a core portion, a first magnet, and a second magnet. The core portion has an electrical output and can move from a first disposition to a second disposition. The first magnet is disposed to provide first magnetic field lines therethrough in a first direction. The second magnet is disposed to provide second magnetic field lines therethrough in a second direction. The core portion, the first magnet and the second magnet are arranged such that externally applied vibrations in a third direction normal to the first direction cause the core portion to oscillate between the first disposition and the second disposition.