Abstract
This paper treats a portable generator that contains a coil and a permanent magnet attached to a spring. Performance of the generator is estimated from power spectral density of acceleration on a walking human body. Experimental results show frequency of vibration produced at trunk is 1.85 Hz, while vibration at upper arm and shank is 0.9 Hz. Maximum power is obtained when the natural frequency of the spring-mass system is coincided with frequency of the vibration. it is found that maximum power generated by a generator at trunk, at upper arm and at shank reach 26.6mW, 13.1mW and 131.6mW, respectively.
