A gear train assembly includes a planetary gear set partially submerged in an oil bath and having a plurality of planetary gears mounted on a rotatable carrier. The knock sensor is secured onto a mounting seat formed on the engine for detecting vibration thereof transmitted to a piezoelectric element from the mounting seat through the main cylindrical metal member. A wireless power receiver on the first port includes a rectifier for converting the RF signal to a DC signal when the antenna couples to radiation in the near-field radiation band in a coupling-mode region of the antenna. The apparatus can have a piston and handle arrangement that can reduce wear of the apparatus. An average torque current value over a period of time corresponding to the variation cycle is calculated, and the average torque current value is compared with a set threshold to perform load weight determination. The distribution images are read out from the positions moved correspondingly to the turns from the start position on the image following the photograph image.