Feasibility study for life event sensor on big field data Life event sensor is an activity recognition sensor both for measuring electric power and for detecting usage of electronic devices by utilizing high frequency current waveform as a signature of each device. To discuss the feasibility of the sensor, we have constructed a long-term data collection system and installed the system in five occupied houses. Discussion about feasibility of the life event sensor on long-term field data and experimental data on a test bed, which can simulate several conditions of power line, is described in this paper.