Provided is an energy harvester (10) comprising a support member (12) to be exposed to ambient mechanical impulses, a transducer (36), wherein the transducer is arranged such as to permit vibrations of the transducer at a first frequency upon excitation by mechanical impact to thereby convert mechanical energy to electric power, and an impact member (20) for actively or passively providing a mechanical impact to the transducer, wherein one or both of the impact member and the transducer is/are coupled with the support member via a spring mechanism, allowing the impact member and/or the transducer to oscillate with regard to the support member upon exposure of the support member to ambient mechanical impulses, wherein a natural frequency of said oscillation(s) of the impact member and/or the transducer is lower than the first frequency, and wherein the transducer and the impact member are arranged relative to each other such that the impact member and the transducer collide if the amplitude of said oscillation(s) of the impact member and/or the transducer exceeds a threshold value to thereby exert said mechanical impact on the transducer.